NOAA Technical Memorandum NMFS-NE-181

Characterization of the Fishing Practices

and Marine Benthic Ecosystems

of the Northeast U.S. Shelf,

and an Evaluation

of the Potential Effects

of Fishing on Essential Fish Habitat

U. S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Northeast Fisheries Science Center

Woods Hole, Massachusetts

January 2004
164. An Overview of the Social and Economic Survey Administered during Round II of the Northeast Multispecies Fishery

Disaster Assistance Program. By Julia Olson and Patricia M. Clay. December 2001. v + 69 p., 3 figs., 18 tables, 2 app. NTIS Access.

No. PB2002-105406.

165. A Baseline Socioeconomic Study of Massachusetts’ Marine Recreational Fisheries. By Ronald J. Salz, David K. Loomis,

Michael R. Ross, and Scott R. Steinback. December 2001. viii + 129 p., 1 fig., 81 tables, 4 app. NTIS Access. No. PB2002-108348.

166. Report on the Third Northwest Atlantic Herring Acoustic Workshop, University of Maine Darling Marine Center,

Walpole, Maine, March 13-14, 2001. By William L. Michaels, editor and coconvenor, and Philip Yund, coconvenor. December 2001.

iv + 18 p., 14 figs., 2 app. NTIS Access. No. PB2003-101556.

167. Assessment and Characterization of Salt Marshes in the Arthur Kill (New York and New Jersey) Replanted after a Severe

Oil Spill. By David B. Packer, ed. December 2001. x + 228 p., 54 figs., 58 tables, 6 app. NTIS Access. No. PB2004-106067.

168. U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments – 2001. By Gordon T. Waring, Janeen M. Quintal, and

Steven L. Swartz, eds., Phillip J. Clapham, Timothy V.N. Cole, Carol P. Fairfield, Aleta Hohn, Debra L. Palka, Marjorie C. Rossman, U.S.

Fish and Wildlife Service, and Cynthia Yeung, contribs. December 2001. vii + 310 p., 43 figs., 54 tables, 2 app. NTIS Access. No. PB2002-

104350.

169. U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments – 2002. By Gordon T. Waring, Janeen M. Quintal, and

Carol P. Fairfield, eds., Phillip J. Clapham, Timothy V.N. Cole, Lance P. Garrison, Georgia Department of Natural Resources, Aleta A. Hohn,

Blair G. Maise, Wayne E. McFee, Debra L. Palka, Patricia E. Rosel, Marjorie C. Rossman, U.S. Fish and Wildlife Service, Frederick W. Wenzel,

and Cynthia Yeung, contribs. September 2002. vii + 318 p., 42 figs., 56 tables, 4 app. NTIS Access. No. PB2003-104167.

170. Interaction of Shelf Water with Warm-Core Rings, Focusing on the Kinematics and Statistics of Shelf Water Entrained

within Streamers. By Ronald J. Schlitz. March 2003. v + 35 p., 26 figs., 3 tables. NTIS Access. No. PB2005-100158.

171. Length-Weight Relationships for 74 Fish Species Collected during NEFSC Research Vessel Bottom Trawl Surveys. By

Susan E. Wigley, Holly M. McBride, and Nancy J. McHugh. March 2003. vi + 26 p., 1 fig., 3 tables. NTIS Access. No. PB2003-106486.

172. Variability of Temperature and Salinity in the Middle Atlantic Bight and Gulf of Maine Based on Data Collected as

Part of the MARMAP Ships of Opportunity Program, 1978-2001. By Jack W. Jossi and Robert L. Benway. March 2003. vi + 92

p., 74 figs., 5 tables. NTIS Access. No. PB2004-100835.

173. Essential Fish Habitat Source Document: Barndoor Skate, Dipturus laevis, Life History and Habitat Characteristics. By

David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 23 p., 14 figs., 1 table. NTIS Access. No. PB2003-104257.

174. Essential Fish Habitat Source Document: Clearnose Skate, Raja eglanteria, Life History and Habitat Characteristics.

By David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 50 p., 25 figs., 2 tables. NTIS Access. No. PB2003-

104260.

175. Essential Fish Habitat Source Document: Little Skate, Leucoraja erinacea, Life History and Habitat Characteristics. By

David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 66 p., 27 figs., 2 tables. NTIS Access. No. PB2003-104259.

176. Essential Fish Habitat Source Document: Rosette Skate, Leucoraja garmani virginica, Life History and Habitat

Characteristics. By David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 17 p., 11 figs., 1 table. NTIS Access.

No. PB2003-104258.

177. Essential Fish Habitat Source Document: Smooth Skate, Malacoraja senta, Life History and Habitat Characteristics. By

David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 26 p., 15 figs., 1 table. NTIS Access. No. PB2003-104256.

178. Essential Fish Habitat Source Document: Thorny Skate, Amblyraja radiata, Life History and Habitat Characteristics. By

David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 39 p., 18 figs., 2 tables. NTIS Access. No. PB2003-104255.

179. Essential Fish Habitat Source Document: Winter Skate, Leucoraja ocellata, Life History and Habitat Characteristics.

By David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 57 p., 25 figs., 2 tables. NTIS Access. No. PB2003-

104254.

180. Variability in Blood Chemistry of Yellowtail Flounder, Limanda ferruginea, with Regard to Sex, Season, and Geographic

Location. By Renee Mercaldo-Allen, Margaret A. Dawson, Catherine A. Kuropat, and Diane Kapareiko. September 2003. vi + 20 p., 1

fig., 10 tables. NTIS Access. No. PB2004-107074.

Recent Issues in This Series
U. S. DEPARTMENT OF COMMERCE

Donald L. Evans, Secretary

National Oceanic and Atmospheric Administration

Vice Admiral Conrad C. Lautenbacher, Jr., USN (ret.), Administrator

National Marine Fisheries Service

William T. Hogarth, Assistant Administrator for Fisheries

Northeast Fisheries Science Center

Woods Hole, Massachusetts

January 2004

David Stevenson1,3, Louis Chiarella1,4, Dianne Stephan1,5,

Robert Reid2,6, Kurt Wilhelm1,7, John McCarthy2,8, and Michael Pentony1,9

This series represents a secondary level of scientific publishing. All issues employ

thorough internal scientific review; some issues employ external scientific review.

Reviews are -- by design -- transparent collegial reviews, not anonymous peer

reviews. All issues may be cited in formal scientific communications.

NOAA Technical Memorandum NMFS-NE-181

Characterization of the Fishing Practices

and Marine Benthic Ecosystems

of the Northeast U.S. Shelf,

and an Evaluation of the Potential Effects

of Fishing on Essential Fish Habitat

Postal Address: 1National Marine Fisheries Serv., 1 Blackburn Dr., Gloucester, MA 01930

2

National Marine Fisheries Serv., 74 Magruder Rd., Highlands, NJ 07732

E-Mail Address: 3David.Stevenson@noaa.gov, 4Lou.Chiarella@noaa.gov, 5Dianne.Stephan@noaa.gov,

6

Robert.Reid@noaa.gov, 7Kurt.Wilhelm@noaa.gov, 8John.McCarthy@noaa.gov, and

9

Michael.Pentony@noaa.gov
Editorial Notes

Publication Date: This document was both submitted and accepted on January 6, 2004, for issuance in this series.

Consequently, the issue number (i.e., 181) and publication date (i.e., January 2004) were assigned at that time. Subsequent

to that time, some new information was added and some existing information was revised. These actions explain why some

post-January 2004 data, as well as some 2005 literature citations, appear in a document with a January 2004 publication

date.

Species Names: The NMFS Northeast Region's policy on the use of species names in all technical communications is

generally to follow the American Fisheries Society's lists of scientific and common names for fishes (i.e., Nelson et al.

2004a

; Robins et al. 1991b), mollusks (i.e., Turgeon et al. 1998c), and decapod crustaceans (i.e., Williams et al. 1989d), and

to follow the Society for Marine Mammalogy's guidance on scientific and common names for marine mammals (i.e., Rice

1998e). Exceptions to this policy occur when there are subsequent compelling revisions in the classifications of species,

resulting in changes in the names of species.

Statistical Terms: The NEFSC Editorial Office’s policy on the use of statistical terms in all technical communications is

generally to follow the International Standards Organization’s handbook of statistical methods (i.e., ISO 1981f

).

Internet Availability: This issue of the NOAA Technical Memorandum NMFS-NE series is being copublished, i.e., as

both a paper and Web document. The Web document, which will be in HTML (and thus searchable) and PDF formats,

can be accessed at: http://www.nefsc.noaa.gov/nefsc/publications/.

a

Nelson, J.S.; Crossman, E.J.; Espinosa-Pérez, H.; Findley, L.T.; Gilbert, C.R.; Lea, R.N.; Williams, J.D. 2004. Common and scientific names

of fishes from the United States, Canada, and Mexico. 6th ed. Amer. Fish. Soc. Spec. Publ. 29; 386 p. b

Robins, C.R. (chair); Bailey, R.M.; Bond, C.E.; Brooker, J.R.; Lachner, E.A.; Lea, R.N.; Scott, W.B. 1991. World fishes important to

North Americans. Amer. Fish. Soc. Spec. Publ. 21; 243 p. c

Turgeon, D.D. (chair); Quinn, J.F., Jr.; Bogan, A.E.; Coan, E.V.; Hochberg, F.G.; Lyons, W.G.; Mikkelsen, P.M.; Neves, R.J.; Roper, C.F.E.;

Rosenberg, G.; Roth, B.; Scheltema, A.; Thompson, F.G.; Vecchione, M.; Williams, J.D. 1998. Common and scientific names of aquatic

invertebrates from the United States and Canada: mollusks. 2nd ed. Amer. Fish. Soc. Spec. Publ. 26; 526 p. d

Williams, A.B. (chair); Abele, L.G.; Felder, D.L.; Hobbs, H.H., Jr.; Manning, R.B.; McLaughlin, P.A.; Pérez Farfante, I. 1989. Common

and scientific names of aquatic invertebrates from the United States and Canada: decapod crustaceans. Amer. Fish. Soc. Spec. Publ.

17; 77 p. e

Rice, D.W. 1998. Marine mammals of the world: systematics and distribution. Soc. Mar. Mammal. Spec. Publ. 4; 231 p. f

ISO [International Organization for Standardization]. 1981. ISO standards handbook 3: statistical methods. 2nd ed. Geneva, Switzerland:

ISO; 449 p.
Page iii

Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

1. Introduction ................................................................................ 1

2. Habitat Characterization of the Northeast U.S. Shelf Ecosystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Habitat Functions and Associations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Regional Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Gulf of Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Georges Bank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Mid-Atlantic Bight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Continental Slope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Coastal and Estuarine Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Regional Benthic Invertebrate Communities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

New England . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Mid-Atlantic Bight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3. Fishing Gear and Practices Used in the Northeast Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Bottom-Tending Mobile Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Bottom Trawls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Otter Trawls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Pair Trawls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Danish and Scottish Seines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Hydraulic Clam Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Atlantic Surfclam and Ocean Quahog Fishery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Softshell Clam Fishery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Sea Scallop Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Other Nonhydraulic Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Quahog Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Oyster, Crab, Mussel, and Whelk Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Bay Scallop Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Sea Urchin Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Seines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Beach Haul Seines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Long Haul Seines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Stop Seines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Bottom-Tending Static Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Lobster Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Fish Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Crab Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Whelk Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Trap Nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Fish Pound Nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Fyke Nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Weirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Floating Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Bottom Gill Nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Sink/Anchor Gill Nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Stake Gill Nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Run-Around Gill Nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Bottom Longlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Pelagic Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Mid-Water Trawls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Paired Mid-Water Trawls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Purse Seines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Drift Gill Nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Pelagic Longline Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Troll Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Page iv

Other Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Rakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Tongs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Line Fishing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Hand Lines/Rod and Reel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Mechanized Line Fishing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Hand Hoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Diving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Spears and Harpoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

4. Geographic Distribution of Fishing Activity by Gear Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Data Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Data Portrayal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Bottom Otter Trawls -- Fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Bottom Otter Trawls -- Shrimp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Bottom Otter Trawls -- Sea Scallops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Scallop Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Hydraulic Clam Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Bottom Longlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Bottom Gill Nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Lobster Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Fish Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Whelk Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Crab Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Hagfish Pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

5. Review of Literature on Fishing Gear Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Individual Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Otter Trawls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Mud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Sand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Gravel/Rocky Substrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Mixed Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

New Bedford-Style Scallop Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Sand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Mixed Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Toothed Scallop Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Sand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Biogenic Substrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Mixed Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Other Nonhydraulic Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Biogenic Substrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Hydraulic Clam Dredges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Mud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Sand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Mixed Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Biogenic Substrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Pots and Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Mixed Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Multiple Gear Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Sand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Gravel/Rock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Mixed Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Page v

6. Vulnerability of Essential Fish Habitat to Bottom-Tending Fishing Gears . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Information Needs and Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Evaluation Methods and Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Life Stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Habitat Scoring and Ranking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Gear Types, Scoring, and Ranking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

EFH Vulnerability Ranking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

7. References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

Tables

Table 2.1. Gulf of Maine benthic assemblages as identified by Watling (1998) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Table 2.2. Comparison of two studies of demersal fish assemblages of Georges Bank and Gulf of Maine . . . . . . . . 17

Table 2.3. Substrate associations with five finfish aggregations on Stellwagen Bank, Gulf of Maine . . . . . . . . . . . . 18

Table 2.4. Sedimentary provinces and associated benthic landscapes of Georges Bank . . . . . . . . . . . . . . . . . . . . . . 19

Table 2.5. Mid-Atlantic habitat types, with characteristic macrofauna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Table 2.6. Major recurrent demersal finfish assemblages of the Mid-Atlantic Bight during spring and fall . . . . . . . 20

Table 2.7. Mid-Atlantic reef types, location, and representative flora and fauna . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 2.8. Faunal zones of the continental slope of Georges Bank and Southern New England . . . . . . . . . . . . . . . . 22

Table 2.9. Habitat types for the canyons of Georges Bank, including characteristic fauna . . . . . . . . . . . . . . . . . . . . 22

Table 2.10. Habitat associations, and importance as prey for fish, of 24 select genera and species of benthic

invertebrates in New England . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Table 2.11. Habitat associations of 14 of 24 select genera and species of benthic invertebrates in the Mid-Atlantic 

Bight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Table 3.1. Percentage of landings for federally managed species and species groups by fishing gear type in the

Northeast Region in 2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 3.2. Percentage of landings for all species by fishing gear type for states in the Northeast Region in 2004 . . 58

Table 3.3. Fishing gears and techniques used in the Northeast Region, categorized by the waters in which they are

used, by whether or not they contact the bottom, and by whether or not their use is regulated by federal

FMPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 4.1 Total number of trips by gear type in the FVTR database for 1995-2000, before and after removing trips

that did not meet the criteria established for analysis, and the percentage of analyzed trips . . . . . . . . . . . 64

Table 4.2. Fishing activity reported by federally-permitted fishing vessels using mobile, bottom-tending gears in the

Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Table 4.3. Fishing activity reported by federally-permitted fishing vessels using fixed gear in the Northeast Region 

during 1995-2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Table 5.1. Number of studies included in this review, by gear and substrate type . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Table 5.2. Number of studies included in this review, by substrate type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Table 5.3. Number of studies included in this review, by geographical area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Table 5.4. Effects of otter trawls on mud substrate habitat: summary of published studies . . . . . . . . . . . . . . . . . . . 112

Table 5.5. Effects of otter trawls on sand substrate habitat: summary of published studies . . . . . . . . . . . . . . . . . . . 114

Table 5.6. Effects of otter trawls on gravel/rock substrate habitat: summary of published studies . . . . . . . . . . . . . . 116

Table 5.7. Effects of otter trawls on mixed substrate habitat: summary of published studies . . . . . . . . . . . . . . . . . . 116

Table 5.8. Effects of New Bedford-style scallop dredges on sand habitat: summary of published studies . . . . . . . . 117

Table 5.9. Effects of New Bedford-style scallop dredges on mixed substrate habitat: summary of published 

studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Table 5.10. Effects of toothed scallop dredges on sand substrate habitat: summary of published studies . . . . . . . . . 118

Table 5.11. Effects of toothed scallop dredges on biogenic substrate habitat: summary of published studies . . . . . . 119

Table 5.12. Effects of toothed scallop dredges on mixed substrate habitat: summary of published studies . . . . . . . . 119

Table 5.13. Effects of other nonhydraulic dredges on biogenic substrate habitat: summary of published studies . . . 120

Table 5.14. Effects of hydraulic clam dredges on mud substrate habitat: summary of published studies . . . . . . . . . . 120

Table 5.15. Effects of hydraulic clam dredges on sand substrate habitat: summary of published studies . . . . . . . . . 121

Table 5.16. Effects of hydraulic clam dredges on mixed substrate habitat: summary of published studies . . . . . . . . 122

Table 5.17. Effects of hydraulic clam dredges on biogenic substrate habitat: summary of published studies . . . . . . 122

Table 5.18. Effects of pots and traps on mixed substrate habitat: summary of published studies . . . . . . . . . . . . . . . . 122

Table 5.19. Effects of multiple gears on sand substrate habitat: summary of published studies . . . . . . . . . . . . . . . . . 123

Table 5.20. Effects of multiple gears on gravel/rock substrate habitat: summary of published studies . . . . . . . . . . . 123
Page vi

Table 5.21. Effects of multiple gears on mixed substrate habitat: summary of published studies . . . . . . . . . . . . . . . 124

Table 6.1. EFH vulnerability matrix analysis for benthic life stages of federally managed fish and invertebrate 

species in the Northeast U.S. Shelf Ecosystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Table 6.2. American plaice EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Table 6.3. Atlantic cod EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Table 6.4. Atlantic halibut EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Table 6.5. Atlantic herring EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

Table 6.6. Atlantic mackerel EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

Table 6.7. Atlantic salmon EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

Table 6.8. Atlantic surfclam EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Table 6.9. Barndoor skate EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Table 6.10. Black sea bass EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

Table 6.11. Bluefish EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for evaluations . 139

Table 6.12. Butterfish EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

Table 6.13. Clearnose skate EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Table 6.14. Cobia EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for evaluations . . . 141

Table 6.15. Golden deepsea crab EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

Table 6.16. Goosefish EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

Table 6.17. Haddock EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Table 6.18. King mackerel EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Table 6.19. Little skate EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Table 6.20. Longfin inshore squid EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

Table 6.21. Northern shortfin squid EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

Table 6.22. Ocean pout EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Table 6.23. Ocean quahog EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Table 6.24. Offshore hake EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

Table 6.25. Pollock EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for evaluations . 150

Table 6.26. Red deepsea crab EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

Table 6.27. Red drum EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

Table 6.28. Red hake EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Table 6.29. Redfish EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for evaluations . 154
Page vii

Table 6.30. Rosette skate EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Table 6.31. Scup EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for evaluations . . . 156

Table 6.32. Sea scallop EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Table 6.33. Silver hake EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Table 6.34. Smooth skate EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Table 6.35. Spanish mackerel EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Table 6.36. Spiny dogfish EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

Table 6.37. Summer flounder EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

Table 6.38. Thorny skate EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Table 6.39. Tilefish EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for evaluations . 164

Table 6.40. White hake EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Table 6.41. Windowpane EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

Table 6.42. Winter flounder EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

Table 6.43. Winter skate EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

Table 6.44. Witch flounder EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for 

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

Table 6.45. Yellowtail flounder EFH -- vulnerability to effects of bottom-tending fishing gears, and rationale for

evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

Figures

Figure 2.1. Northeast U.S. Shelf Ecosystem, showing the boundaries of the continental shelf, the EEZ, and 

the three principal systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Figure 2.2. Gulf of Maine, showing the 50-fathom and 100-fathom lines of the continental shelf, the boundary 

between the U.S. and Canadian EEZs, and the principal physiographic features . . . . . . . . . . . . . . . . . . . . 26

Figure 2.3. Northeast Region sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 2.4. Water mass circulation patterns in the Georges Bank - Gulf of Maine region . . . . . . . . . . . . . . . . . . . . . . 28

Figure 2.5. Distribution of the seven major benthic assemblages in the Gulf of Maine . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 2.6. Sedimentary provinces of eastern Georges Bank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 2.7. Mid-Atlantic Bight submarine morphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 2.8. Major features of the Mid-Atlantic and Southern New England continental shelf . . . . . . . . . . . . . . . . . . 31

Figure 2.9. Summary of all reef habitats in the Mid-Atlantic Bight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 2.10. Schematic representation of major macrofaunal zones on the Mid-Atlantic shelf . . . . . . . . . . . . . . . . . . . 33

Figure 2.11. Bathymetry of the U.S. Atlantic continental margin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 2.12. Geographic distribution of the density and biomass of all taxonomic groups of benthic invertebrates in the 

New England region, 1956-1965 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Figure 2.13. Percentage composition and density of the major taxonomic groups of New England benthic invertebrate 

fauna in relation to water depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 2.14. Percentage composition and biomass of the major taxonomic groups of New England benthic invertebrate 

fauna in relation to water depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 2.15. Percentage composition and density and biomass of the major taxonomic groups of New England benthic

invertebrate fauna in relation to bottom type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 2.16. Geographic distribution of the density of all taxonomic groups of benthic invertebrates in the Mid-Atlantic 

region, 1956-1965 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Page viii

Figure 2.17. Geographic distribution of the biomass of all taxonomic groups of benthic invertebrates in the Mid-Atlantic

region, 1956-1965 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 2.18. Percentage composition and density and biomass of the major taxonomic groups of Mid-Atlantic benthic

invertebrate fauna in relation to water depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 2.19. Percentage composition and density and biomass of the major taxonomic groups of Mid-Atlantic benthic

invertebrate fauna in relation to bottom type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Figure 4.1. Location of five year-round groundfish closed areas in the Gulf of Maine - Georges Bank region . . . . . 66

Figure 4.2. Bottom otter trawl (fish) fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . 67

Figure 4.3. Bottom otter trawl (shrimp) fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . 68

Figure 4.4. Bottom otter trawl (scallop) fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . 69

Figure 4.5. Scallop dredge fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . . . . . . . . 70

Figure 4.6. Hydraulic clam dredge fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . 71

Figure 4.7. Bottom longline fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . . . . . . . 72

Figure 4.8. Bottom gill net fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . . . . . . . 73

Figure 4.9. Lobster trap or pot fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . . . . . 74

Figure 4.10. Fish pot fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure 4.11. Whelk pot fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Figure 4.12. Crab pot fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Figure 4.13. Hagfish pot fishing activity in the Northeast Region during 1995-2001 . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Figure 4.14. Number of 10squares within which any amount of fishing activity was reported during 1995-2001 

by gear type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Figure 4.15. Proportion of area fished at the 90th percentile, an index of how evenly distributed the days or trips were 

among 10squares, during 1995-2001 by gear type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Acronyms

ASMFC = Atlantic States Marine Fisheries Commission

EEZ = exclusive economic zone

EFH = essential fish habitat

FMP = fishery management plan

FVTR = fishing vessel trip report

GIS = geographical information system

GOM = Gulf of Maine

HF = heavily fished

LF = lightly fished

MAB = Mid-Atlantic Bight

MAFMC = Mid-Atlantic Fishery Management Council

MBW = Maine Bottom Water

MIW = Maine Intermediate Water

MSA = Magnuson-Stevens Fishery Conservation and Management Act

MSW = Maine Surface Water

NEFMC = New England Fishery Management Council

NMFS = (NOAA) National Marine Fisheries Service

NOAA = (U.S. Department of Commerce) National Oceanic and Atmospheric Administration

PSI = pounds per square inch (lb/in2

)

TMS = 10-minute square (of latitude or longitude) (10square)

UF = unfished
Page ix

PREFACE

This document was conceived in 2001 by the Northeast Region Essential Fish Habitat Steering Committee. At that

time, committee members were Louis Chiarella and Dianne Stephan (NOAA Fisheries Service’s Northeast Regional Office,

Gloucester, MA), Tom Hoff (Mid-Atlantic Fishery Management Council, Dover, DE), Robert Reid (Northeast Fisheries

Science Center (NEFSC), Highlands, NJ), Michael Pentony (New England Fishery Management Council, Newburyport,

MA), and Carrie Selberg (Atlantic States Marine Fisheries Commission). An early draft that included habitat

characterization information, the spatial distribution of fishing activity by gear type, and a summary of relevant gear-effects

studies, was prepared to assist a panel of academic and fishing industry experts that met in October 2001 to assess the habitat

impacts of commercial fishing gear in the region. Following the workshop, these chapters were revised and updated, and

new chapters describing fishing gear and practices and assessing the vulnerability of habitats utilized by federally managed

fish and invertebrate species to fishing were added.

Seven authors collaborated in the preparation of this document. Louis Chiarella prepared the original gear descriptions,

relying partially on information compiled by Michael Pentony. Additional information was later added to this section by

David Stevenson. Dianne Stephan prepared the habitat characterization chapter, in collaboration with Robert Reid and David

Stevenson. David Stevenson prepared the gear distribution maps and summaries, using data provided by Kurt Wilhelm, and

summarized the relevant gear-effects literature. Korie Johnson (NOAA Fisheries Service’s Office of Habitat Conservation,

Silver Spring, MD) assisted with the literature review. Dianne Stephan, Louis Chiarella, Robert Reid, and David Stevenson

collaborated on the habitat vulnerability evaluations. John McCarthy, a contractor at the Howard Laboratory (Highlands,

NJ), assisted with text formatting and the preparation of tables and figures. Meredith Lock, also a contractor at the Howard

Laboratory, helped with literature review and document assembly. Vince Guida (NEFSC, Highlands, NJ) provided some

habitat characterization information. Thomas Noji (NEFSC, Highlands, NJ), David Mountain (NEFSC, Woods Hole, MA),

and Peter Colosi (Northeast Regional Office, Gloucester, MA) commented on an early draft. David Packer (NEFSC,

Highlands, NJ) and Jon Gibson (NEFSC, Woods Hole, MA) edited the document.

Page 1

1. INTRODUCTION

This document was developed to provide assistance in

meeting the Essential Fish Habitat (EFH) mandates of the

Magnuson-Stevens Fishery Conservation and Management Act (MSA) for the NOAA Fisheries Service’s

Northeast Region (hereafter just “Northeast Region” or

“the region”) which ranges from Maine to North Carolina.

The 1996 amendments to the MSA require that federal

fishery management plans (hereafter just “FMPs”)

minimize, to the extent practicable, adverse effects on EFH

caused by fishing [MSA Section 303(a)(7)]. Pursuant to the

EFH regulations [50 CFR 610.815(a)(2)], FMPs must include

an evaluation of the potential adverse effects of fishing on

EFH, including the effects of fishing activities regulated

under other federal FMPs. The evaluation should consider

the effects of each fishing activity on each type of habitat

found within EFH, and provide conclusions as to whether

and how each fishing activity adversely affects EFH. FMPs

must describe each fishing activity, and must review and

discuss all available and relevant information such as

information regarding the intensity, extent, and frequency

of any adverse effect on EFH, the type of habitat within

EFH that may be adversely affected, and the habitat

functions that may be disturbed. The evaluation should

also consider the cumulative effects of multiple fishing

activities on EFH. Additionally, FMPs must identify any

fishing activities that are not managed under the MSA that

may adversely affect EFH. Such activities may include

fishing managed by state agencies or other authorities.

However, regional fishery management councils (hereafter

just “councils”) are not required to take action to minimize

adverse effects from non-MSA fishing activities. In

completing this evaluation, councils are expected to use the

best scientific information available, as well as other

appropriate information sources.

This document emphasizes those fishing gears

directly managed by the New England Fishery Management Council (NEFMC) and Mid-Atlantic Fishery Management Council (MAFMC). Much of the information included

in earlier drafts of this document was incorporated into

recent environmental impact statements and amendments

to NEFMC FMPs for Atlantic sea scallops, groundfish, and

monkfish (goosefish) (NEFMC 2003a,b, 2004), and into an

environmental impact statement that evaluated the effects

of gears used in the Atlantic herring fishery on EFH

(NOAA/NMFS 2005). The information in this document

relates strictly to the direct physical and biological effects

of fishing on benthic habitat; it does not include resource

population effects or ecosystem-level effects that are

caused by the removal of targeted species or bycatch.

The information used in this document includes

descriptions of benthic habitats and species assemblages

(fish and invertebrates) in four subregions of the Northeast

U.S. Shelf Ecosystem, descriptions of 37 gear types used in

state and federal waters in the region, and the extent and

distribution of fishing activity for the major commercial

fishing gears used in the region during 1995-2001. In

addition, this document summarizes the results of 73

scientific studies that form the basis for understanding the

effects of fishing on benthic marine habitats in the region,

and evaluates the vulnerability of benthic EFH to fishing

for 47 species of federally managed fish and invertebrate

species in the region. Conclusions reached by a panel of

experts that met in October 2001 for the purpose of

evaluating habitat effects in the Northeast Region

(NREFHSC 2002) were also incorporated. A preliminary

draft of this document was distributed to the workshop

panelists to assist them in conducting their evaluation.
Page 2

2. HABITAT CHARACTERIZATION OF THE NORTHEAST U.S. SHELF ECOSYSTEM

The Northeast U.S. Shelf Ecosystem includes a broad

range of habitats with varying physical and biological

properties. From the cold waters of the Gulf of Maine

(GOM) south to the more tempered climate of the MidAtlantic Bight (MAB), oceanographic and biological

processes interact to form a network of expansively to

narrowly distributed habitat types. This chapter provides a

portion of the background information needed to evaluate

the effects of fishing on benthic habitats in the region by:

1) reviewing habitat functions and associations; 2)

describing four regional systems and their associated

physical and benthic biological features; 3) covering the

habitat aspects of coastal and estuarine features; and 4)

describing benthic invertebrate communities in New

England and the MAB, and their distribution in relation to

depth and sediment type.

HABITAT FUNCTIONS AND ASSOCIATIONS

From a biological perspective, habitats provide living

things with the basic life requirements of nourishment and

shelter. Habitats may also provide a broader range of

benefits to the ecosystem, such as the way seagrasses

physically stabilize the substrate and help recirculate

oxygen and nutrients. This section, however, focuses on

how benthic marine habitats provide food and shelter for

federally managed species in the Northeast Region.

The spatial and temporal variation of prey abundance

influences the survival, recruitment, development, and

spatial distribution of organisms at every trophic level

above primary producers. For example, the abundance and

distribution of planktonic organisms greatly influence the

growth, survival, and distribution of fish larvae. In

addition, the migratory behavior of juvenile and adult fish

is directly related to seasonal patterns of prey abundance

and changes in environmental conditions, especially water

temperature. Prey supply is particularly critical for the

starvation-prone, early-life-history stages of fish.

The availability of food for planktivores is highly

influenced by oceanographic properties. The seasonal

warming of surface waters in temperate latitudes produces

vertical stratification of the water column which isolates

sunlit surface waters from deeper, nutrient-rich water,

leading to reduced primary productivity. In certain areas,

upwelling, induced by wind, storms, and tidal mixing, inject

nutrients back into the photic zone, stimulating primary

production. Changes in primary production from upwelling

and other oceanographic processes affect the amount of

organic matter available for other organisms higher up in

the food web, and thus influence their abundance and

distribution. Some of the organic matter produced in the

photic zone sinks to the bottom and provides food for

benthic organisms. In shallower water, benthic macroalgae

and microalgae also contribute to primary production.

Recent research on benthic primary productivity indicates

that benthic microalgae may contribute more to primary

production than has been originally estimated (Cahoon

1999).

Benthic organisms provide an important food source

for many fish species. Bottom-dwelling sand lances are

eaten by many fish, and benthic invertebrates are the main

source of nutrition for many demersal fish. Temporal and

spatial variations in benthic community structure affect the

distribution and abundance of bottom-feeding fish.

Likewise, the abundance and species composition of

benthic communities are affected by a number of

environmental factors, including temperature, sediment

type, and the availability of organic matter.

A number of recent studies have focused on the

habitat associations of juvenile demersal fish. In shallow,

coastal waters of the Northeast Region, effects of physical

habitat factors and prey availability on the abundance and

distribution of young-of-the-year flounder (various species) have been investigated in nearshore and estuarine

habitats in Connecticut, New Jersey, and North Carolina

(Rountree and Able 1992; Howell et al. 1999; Walsh et al.

1999; Manderson et al. 2000; Phelan et al. 2001; Stoner et

al. 2001). There are few comparable studies of more open,

continental shelf environments. In the Northeast Region,

Steves et al. (1999) identified depth, bottom temperature,

and time of year as primary factors delineating settlement

and nursery habitats for juvenile silver hake and yellowtail

flounder in the MAB. Also, in a series of publications,

Auster et al. (1991, 1995, 1997) correlated the spatial

distributions of juvenile benthic fish (e.g., silver hake) with

changes in microhabitat type on sand bottom at various

open shelf locations in Southern New England.

In addition to providing food sources, another

important functional value of benthic habitat is the shelter

and refuge from predators provided by structure. Threedimensional structure is provided by physical features

such as boulders, gravel and cobble, sand waves and

ripples, and mounts, burrows and depressions created by

organisms. Structure is also provided by emergent

epifauna such as sponges, bryozoans, anemones, mussels,

tunicates, and corals.

The importance of benthic habitat complexity was

discussed by Auster (1998) and Auster and Langton

(1999). They developed a conceptual model that compared

fishing gear effects across a gradient of habitat types.

Based on this model, habitat value increases with increased

structural complexity, from the lowest value in flat sand and

mud to the highest value in piled boulders. The importance

of habitat complexity to federally managed species is a key

issue in the Northeast Region. Whether, and to what

degree, the removal of emergent epifauna from gravel and

rocky bottom habitats affects the survival of juvenile

Atlantic cod and other species is of particular concern.

Field studies (in the northeastern United States and eastern
Page 3

Canadian waters, and other locations), laboratory experiments, and modeling studies have addressed the issue of

removal of emergent epifauna. Because of the importance

of this issue in the Northeast Region, this research is

summarized below.

The first field study linking survival of juvenile

Atlantic cod and haddock to habitat type on Georges Bank

was by Lough et al. (1989). Using submersibles, they

observed that recently settled age-0 juvenile Atlantic cod

(and haddock), <10 cm long, were primarily found in

pebble-gravel habitat at 70-100 m depths on eastern

Georges Bank. They hypothesized that the gravel

enhanced survival through predator avoidance; coloration

of the fish mimicked that of the substrate, and from the

submersible the fish were very difficult to detect against

the gravel background. The authors considered increased

prey abundance to be another, but less likely, explanation

for the concentration of these fish on gravel. Presence of

emergent epifauna, and any effects of epifauna on survival

of the juveniles, were not noted.

Gregory and Anderson (1997), using submersibles in

18-150 m depths in Placentia Bay, Newfoundland, similarly

found that the youngest Atlantic cod observed (age 1, 10-

12 cm long) were primarily associated with low-relief gravel

substrate; their mottled color appeared to provide

camouflage in the gravel. Older juveniles (ages 2-4) were

most abundant in higher relief areas with coarser substrate

(e.g., submarine cliffs). No selection by juvenile Atlantic

cod for substrates with macroalgae cover was seen, and

emergent epifauna was not mentioned.

In the first study suggesting an added value of

emergent epifauna on Georges Bank gravel, Valentine and

Lough (1991) observed from submersibles that attached

epifauna was much more abundant in areas of eastern

Georges Bank that had not been fished (due to the

presence of large boulders). They felt the increased bottom

complexity provided by the epifauna might be an important

component of fisheries habitat, but both trawled and

untrawled gravel habitats were considered important for

survival of juvenile Atlantic cod.

Other field studies on the relationship between

juvenile Atlantic cod abundance and habitat complexity

have been in shallower inshore waters, and results may not

be directly applicable to conditions on offshore banks like

Georges Bank. In 2-12 m depths off the Newfoundland

coast, Keats et al. (1987) found [in contrast to Gregory and

Anderson (1997), above] juvenile Atlantic cod to be much

more abundant in macroalgae beds than in adjacent areas

which had been grazed bare by sea urchins. This was true

of 1-yr-old fish (7.8-12.5 cm) as well as older, larger (12.6-

23.5 cm) juveniles. The larger fish fed on fauna associated

with the macroalgae, so enhanced food supply was a

probable benefit of the increased complexity. The smallest

1-yr-olds fed on plankton, and it was unlikely their growth

was affected by presence of macroalgae.

Tupper and Boutilier (1995a) examined four habitat

types (sand, seagrass, cobble, and rock reef) in St.

Margaret’s Bay, Nova Scotia, and reported that Atlantic

cod settlement was equal in all habitats, but survival and

juvenile densities were higher in the more complex habitats.

Growth rate was highest in seagrass beds, but predator

(larger Atlantic cod) efficiency was lowest, and juvenile

survival highest, on rock reef and cobble. The authors

considered the different habitats to provide a tradeoff

between enhanced foraging success and increased

predation risk. In another study in St. Margaret’s Bay,

Tupper and Boutilier (1995b) found that Atlantic cod

settling on a rocky reef inhabited crevices in the reef, and

defended territories around the crevices. Fish that settled

earlier and at larger sizes grew more quickly and had larger

territories. Size at settlement and timing of settlement were

thus considered important in determining competitive

success of individuals.

Habitat associations of juvenile Atlantic cod were also

examined by Gotceitas et al. (1997) using SCUBA divers in

Trinity Bay, and beach seines in Trinity, Notre Dame, and

Bonavista Bays, Newfoundland. In both types of surveys,

almost all age-0 Atlantic cod were found in eelgrass beds as

opposed to less structurally complex areas, and eelgrass

was suggested to be an important habitat for these fish.

Older juveniles were more abundant on mud, sand, and

rocky bottoms than in eelgrass.

A seining study by Linehan et al. (2001) in Bonavista

Bay, Newfoundland, found age-0 Atlantic cod (<10 cm

long) to be more abundant in vegetated (eelgrass) than in

unvegetated habitats, both day and night. However,

potential predators of juvenile Atlantic cod were also most

abundant in eelgrass. Tethering experiments with age-0

Atlantic cod at six sites in 0.7-20 m depths indicated that

predation increased with depth, being about three times

higher at deeper sites. At shallow sites, predation was

generally higher in unvegetated sites than in eelgrass.

Habitat use of age-0 and -1 Atlantic cod in state waters

off eastern Massachusetts is discussed by Howe et al.

(2000), based on analysis of 22 yr (1978-1999) of data from

spring and fall trawl surveys by the Massachusetts

Division of Marine Fisheries. Results showed the survey

area is important for Atlantic cod settlement, with at least

two pulses of newly settled fish found in most years.

Spatial distribution patterns of young Atlantic cod were

clear, stable, and strongly related to depth. In spring, justsettled Atlantic cod were most abundant in depths <27 m;

in fall these age-0 Atlantic cod were found in 9-55 m depths,

but were concentrated in 27-55 m. Age-1 Atlantic cod were

more abundant in deeper waters (18-55 m in spring, 37-55 m

in fall). Habitat complexity per se was not the primary focus

of this analysis, and some of the most complex (e.g., rocky)

habitats could not be sampled by the survey. However, the

greater abundance of just-settled fish in shallower waters

was thought to be linked to the higher complexity of these

habitats. It was postulated that high densities of age-0 fish

indicated areas of high productivity and preferred habitat.

Given the abundance of juvenile Atlantic cod in these

surveys, eastern Massachusetts waters were recom-
Page 4

mended as a coastal “Habitat Area of Particular Concern”

for the GOM Atlantic cod stock.

Kaiser et al. (1999) analyzed beam trawl catch data from

a number of stations in the English Channel and reported

that small gadoid species were present in deeper (>30 m),

structurally complex habitats with rocks, soft corals,

bryozoans, hydroids, and sponges, and were absent in

shallow water habitats which were inhabited by several

species of flounder. Most of the structure-forming benthic

species that were present in deeper water were also present

in shallow water, but at reduced abundances, and the total

biomass of sessile epibenthic species was higher in

shallow water. These results suggest that depth and the

amount of cover provided by certain types of emergent

epifauna (e.g., sponges) were the most important factors

affecting habitat utilization by gadoid (and flounder)

species.

Information on the effects of habitat complexity on

juvenile Atlantic cod survival is also available from several

laboratory studies. Gotceitas and Brown (1993) compared

substrate preferences of juvenile Atlantic cod (6-12 cm) for

sand, gravel-pebble, and cobble, before and after

introduction of a larger Atlantic cod. Before the predator

was introduced, small Atlantic cod preferred sand or

gravel-pebble over cobble. In the presence of the predator,

they chose cobble if available, and the cobble reduced

predation. The experiment did not test effects of emergent

epifauna on substrate choices or survival. Gotceitas et al.

(1995) conducted a similar study, but with 3.5-8 cm Atlantic

cod in a tank with one of two combinations of three

substrates: 1) sand, gravel, and 30-cm long strips of plastic

to simulate kelp (Laminaria sp.); or 2) sand, cobble, and

“kelp.” Based on the authors’ earlier study, cobble was

considered to provide a “safe” habitat that reduced

predation. Responses to introduction of two kinds of

larger Atlantic cod were tested: fish that actively attempted

to eat the smaller Atlantic cod, versus “passive” predators

that showed no interest in the smaller fish. In the presence

of passive predators, small Atlantic cod preferred sand

substrates and avoided kelp. When exposed to an active

predator, they hid in cobble if available or kelp if there was

no cobble. Both cobble and kelp significantly reduced

predation, and small Atlantic cod appeared able to modify

their behavior based on the varying risk presented by

different predators.

Fraser et al. (1996) tested responses of age-0 (5.2-8.2

cm) and age-1 (10.2-13.5 cm) Atlantic cod to predators (3-yr

old Atlantic cod), using the same tanks as Gotceitas et al.

(1995), but with only two substrate choices: sand versus

gravel, and sand versus cobble. With no predator present,

age-0 or -1 Atlantic cod by themselves preferred sand to

gravel or cobble, but if both age-0 and -1 fish were in the

tank, the smaller fish tended to avoid the larger ones and to

increase use of gravel/cobble. When a predator was

introduced, both age-0 and -1 Atlantic cod hid in cobble if

available; in the sand/gravel trials, they attempted to flee

from the predator. In the predator’s presence, the

avoidance of age-1 Atlantic cod by age-0 Atlantic cod

disappeared; overall, however, there was some indication

of habitat segregation between age-0 and age-1 Atlantic

cod.

Gotceitas et al. (1997) again used the same

experimental system to compare use of sand, gravel, and

cobble substrates, as well as three densities of eelgrass, by

age-0 Atlantic cod (3.5-10 cm) in the presence and absence

of a predator (age-3 Atlantic cod). With no predator, the

small Atlantic cod preferred sand and gravel to cobble.

When a predator was introduced and cobble was present,

age-0 fish hid in the cobble or in dense eelgrass ( 720 stems/

m2

) if present. With no cobble, they hid in all three

densities of eelgrass. Age-0 Atlantic cod survival (time to

capture and number of fish avoiding capture) was highest

in cobble or eelgrass 1000 stems/m2

. In other

combinations, time to capture increased with both

presence and density of vegetation.

Borg et al. (1997) conducted a laboratory study of

habitat choice by two size groups of juvenile Atlantic cod

(7-13 and 17-28 cm TL) on sandy bottoms with different

vegetation types. Four habitats, typical of shallow soft

bottom on the west coast of Sweden, were tested in six

combinations. During daylight, fish preferred vegetation

to bare sand, while at night -- when juvenile Atlantic cod

feed in open, sandy areas -- no significant choice was

made. Both size classes preferred Fucus kelp, the most

complex habitat that was tested.

Lindholm et al. (1999) tested effects of five habitat

types, representing a gradient of complexity, on survival of

age-0 Atlantic cod (7-10 cm) in the presence of age-3

conspecifics. Substrates were sand, cobble, sparse short

sponge, dense short sponge, and tall sponge. Sponge

presence significantly reduced predation compared to that

on sand, with density of sponges being more important

than sponge height. Increasing habitat complexity reduced

the distance from which a predator could react to the prey.

The authors concluded that alteration of seafloor habitat

by fishing could lower survival of juvenile Atlantic cod.

(There was no significant increase in survival in epifauna

compared to bare cobble, however.)

In a mesocosm experiment, Isakkson et al. (1994)

compared the foraging efficiency of Atlantic cod on three

different prey species on bare sand and eel grass with

varying percent cover of filamentous algae. Foraging

efficiency of Atlantic cod on sand shrimp (Crangon

crangon) and green crabs was greatest in unvegetated

substrate. Survival of these two prey species was

significantly enhanced by the addition of moderate

amounts of algal cover to sand substrates. Shore shrimp

(Palaemon adspersus) were equally susceptible to

predation in all habitat types.

The effects of habitat complexity on post-settlement

survival of juvenile Atlantic cod have been examined via

modeling (Lindholm et al. 2001). Data from the Lindholm et

al. (1999) laboratory study described above were used to

assign maximum values for juvenile mortality in the least
Page 5

complex habitats, and in the most complex habitats. Twelve

runs of a dynamic monthly model were made, with the first

run (month) representing settlement of the Atlantic cod.

Results indicated that reduction of habitat complexity by

fishing had significant negative effects on survival of

juvenile Atlantic cod, and that preservation of complexity

through use of marine protected areas could reduce these

negative effects.

Elsewhere and for other species, Charton and Ruzafa

(1998) correlated increased habitat complexity (numbers of

rocky boulders) in the Mediterranean with higher numbers

and abundances of reef fish. There is evidence provided

by laboratory experiments that habitat complexity can

benefit fish that inhabit open, sandy habitats by providing

refuge from bottom currents in the troughs between sand

ripples (Gerstner 1998; Gerstner and Webb 1998).

In some situations, other habitat characteristics may

be equally or more important than complexity. As

discussed above, Lough et al. (1989) hypothesized that

gravel substrate enhanced survival of juvenile Atlantic cod

because the coloration of these juveniles mimicked the

substrate. In a similar example, American plaice adults are

thought to use gravel-sand sediments as a coloration

refuge (Scott 1982). It is apparent that in identifying habitat

value, a broad range of characteristics associated with

habitat structure and function, which may vary by species

and life stage, must be considered. Evaluations cannot be

limited to individual aspects such as substrate type.

Unfortunately, the amount of information available for

individual parameters is limited, especially quantitative

information necessary for multivariate analyses. Further

development of multivariate relationships between biological, chemical, and physical habitat features will increase our

understanding of the marine environment and advance the

evidence of direct links between habitat conditions and

fishery productivity.

REGIONAL SYSTEMS

The Northeast U.S. Shelf Ecosystem (Figure 2.1) has

been described as including the area from the GOM south

to Cape Hatteras, extending from the coast seaward to the

edge of the continental shelf, including the slope sea

offshore to the Gulf Stream (Sherman et al. 1996). The

continental slope includes the area east of the shelf, out to

a depth of 2000 m. Four distinct subregions comprise the

Northeast Region: the GOM, Georges Bank, the MAB, and

the continental slope. Occasionally, another subregion,

Southern New England, is described; however, we

incorporated discussions of any distinctive features of this

area into the sections describing Georges Bank and the

MAB.

The GOM is an enclosed coastal sea, characterized by

relatively cold waters and deep basins, with a patchwork of

various sediment types. Georges Bank is a relatively

shallow coastal plateau that slopes gently from north to

south and has steep submarine canyons on its eastern and

southeastern edge. It is characterized by highly

productive, well-mixed waters and strong currents. The

MAB is comprised of the sandy, relatively flat, gently

sloping continental shelf from Southern New England to

Cape Hatteras, NC. The continental slope begins at the

continental shelf break and continues eastward with

increasing depth until it becomes the continental rise. It is

fairly homogenous, with exceptions at the shelf break,

some of the canyons, the Hudson Shelf Valley, and in areas

of glacially rafted hard bottom.

Pertinent physical and biological characteristics of

each of these subregions are described subsequently in

this section. The first portion of each description

summarizes oceanographic and geologic features, and the

second portion summarizes biological features. Source

references used to describe the general physical features of

these subregions are not cited in the following text, but

include Backus 1987; Schmitz et al. 1987; Tucholke 1987;

Wiebe et al. 1987; Cook 1988; Reid and Steimle 1988;

Stumpf and Biggs 1988; Abernathy 1989; Townsend 1992;

Mountain et al. 1994; Beardsley et al. 1996; Brooks 1996;

Sherman et al. 1996; Dorsey 1998; Kelley 1998; NEFMC

1998; and Steimle et al. 1999b. In some cases, recent or

specific research results are cited in the text. References

used in the biological summaries are also cited in the text.

Gulf of Maine

Physical Features

Although not obvious in appearance, the GOM is

actually an enclosed coastal sea, bounded on the east by

Browns Bank, on the north by the Nova Scotian (Scotian)

Shelf, on the west by the New England states, and on the

south by Cape Cod and Georges Bank (Figure 2.2). The

GOM was glacially derived, and is characterized by a

system of deep basins, moraines, and rocky protrusions

with limited access to the open ocean. This geomorphology influences complex oceanographic processes that

result in a rich biological community.

The GOM is topographically unlike any other part of

the continental border along the U.S. Atlantic coast. The

GOM’s geologic features, when coupled with the vertical

variation in water properties, result in a great diversity of

habitat types. It contains 21 distinct basins separated by

ridges, banks, and swells. The three largest basins are

Wilkinson, Georges, and Jordan (Figure 2.2). Depths in the

basins exceed 250 m, with a maximum depth of 350 m in

Georges Basin, just north of Georges Bank. The Northeast

Channel between Georges Bank and Browns Bank leads

into Georges Basin, and is one of the primary avenues for

exchange of water between the GOM and the North

Atlantic Ocean.

High points within the Gulf include irregular ridges

such as Cashes Ledge which peaks at 9 m below the
Page 6

surface, as well as lower flat-topped banks and gentle

swells. Some of these rises are remnants of the continental

shelf that was left after most of it was removed by the

glaciers. Other rises are glacial moraines, and a few such as

Cashes Ledge are outcroppings of bedrock. Very fine

sediment particles created and eroded by the glaciers have

collected in thick deposits over much of the GOM,

particularly in its deep basins (Figure 2.3). These mud

deposits blanket and obscure the irregularities of the

underlying bedrock, forming topographically smooth

terrains. Some shallower basins are covered with mud as

well, including some in coastal waters. In the rises between

the basins, other materials are usually at the surface.

Unsorted glacial till covers some morainal areas, as on

Sewell Ridge to the north of Georges Basin and on Truxton

Swell to the south of Jordan Basin. Sand predominates on

some high areas, and gravel, sometimes with boulders,

predominates on others.

Coastal sediments exhibit a high degree of smallscale

variability. Bedrock is the predominant substrate along the

western edge of the GOM north of Cape Cod in a narrow

band out to a depth of about 60 m. Rocky areas become

less common with increasing depth, but some rock

outcrops poke through the mud covering the deeper

seafloor. Mud is the second-most common substrate on

the inner continental shelf. Mud predominates in coastal

valleys and basins that often abruptly border rocky

substrates. Many of these basins extend without

interruption into deeper water. Gravel, often mixed with

shell, is common adjacent to bedrock outcrops and in

fractures in the rock. Large expanses of gravel are not

common, but do occur near reworked glacial moraines and

in areas where the seafloor has been scoured by bottom

currents. Gravel is most abundant at depths of 20-40 m,

except in eastern Maine where a gravel-covered plain exists

to depths of at least 100 m. Bottom currents are stronger in

eastern Maine where the mean tidal range exceeds 5 m.

Sandy areas are relatively rare along the inner shelf of the

western GOM, but are more common south of Casco Bay,

especially offshore of sandy beaches.

An intense seasonal cycle of winter cooling and

turnover, springtime freshwater runoff, and summer

warming influences oceanographic and biologic processes

in the GOM. The Gulf has a general counterclockwise

nontidal surface current that flows around its coastal

margin (Figure 2.4). This current is primarily driven by

fresh, cold Scotian Shelf water that enters over the Scotian

Shelf and through the Northeast Channel, and freshwater

river runoff, which is particularly important in the spring.

Dense, relatively warm, and saline slope water entering

through the bottom of the Northeast Channel from the

continental slope also influences gyre formation. Counterclockwise gyres generally form in Jordan, Wilkinson, and

Georges Basins, and in the Northeast Channel as well.

These surface gyres are more pronounced in spring and

summer; with winter, they weaken and become more

influenced by the wind.

Stratification of surface waters during spring and

summer seals off a mid-depth layer of water that preserves

winter salinity and temperatures. This cold layer of water is

called “Maine Intermediate Water” (MIW), and is located

between the more saline Maine Bottom Water (MBW) and

the warmer, stratified Maine Surface Water (MSW). The

stratified MSW is most pronounced in the deep portions of

the western GOM. Tidal mixing of shallow areas prevents

thermal stratification and results in thermal fronts between

the stratified areas and cooler mixed areas. Typically, mixed

areas include Georges Bank, the southwest Scotian Shelf,

eastern Maine coastal waters, and the narrow coastal band

surrounding the remainder of the Gulf.

The Northeast Channel provides an exit for cold MIW

and outgoing MSW, while it allows warmer, more saline

slope water to move in along the bottom and spill into the

deeper basins. The influx of water occurs in pulses, and

appears to be seasonal, with lower flow in late winter and a

maximum in early summer.

GOM circulation and water properties can vary

significantly from year to year. Notable episodic events

include shelf-slope interactions such as the entrainment of

shelf water by Gulf Stream rings (see the “Continental

Slope/Physical Features” section), and strong winds that

can create currents as high as 1.1 m/s over Georges Bank.

Warm-core Gulf Stream rings can also influence upwelling

and nutrient exchange on the Scotian Shelf, and affect the

water masses entering the GOM. Annual and seasonal

inflow variations also affect water circulation.

Internal waves are episodic and can greatly affect the

biological properties of certain habitats. Internal waves

can shift water layers vertically, so that habitats normally

surrounded by cold MIW are temporarily bathed in warm,

organic-rich surface water. On Cashes Ledge, it is thought

that deeper nutrient rich water is driven into the photic

zone, providing for increased productivity. Localized areas

of upwelling interaction occur in numerous places

throughout the Gulf.

Benthic Biological Features

Based on 303 benthic grab samples collected in the

GOM during 1956-1965, Theroux and Wigley (1998)

reported that, in terms of numbers, the most common

groups of benthic invertebrates in the GOM were annelid

worms (35%), bivalve mollusks (33%), and amphipod

crustaceans (14%). Biomass was dominated by bivalve

mollusks (24%), sea cucumbers (22%), sand dollars (18%),

annelids (12%), and sea anemones (9%). Watling (1998)

used numerical classification techniques to separate

benthic invertebrate samples into seven bottom assemblages. Distribution was determined from both quantitative soft-bottom sampling and qualitative hard-bottom

sampling. These assemblages are identified in Table 2.1,

and their distribution is indicated in Figure 2.5. This

classification system considers predominant taxa, sub-
Page 7

strate types, and seawater properties. (See the last section

of this chapter for more information on benthic invertebrate

communities in New England.)

An in-depth review of GOM habitat types has been

prepared by Brown (1993). Although still preliminary, this

classification system is a promising approach. It builds on

a number of other schemes, including Cowardin et al.

(1979), and tailors them to Maine’s marine and estuarine

environments. A significant factor that is included in this

system, but has been neglected in others, is the amount of

“energy” in a habitat. Energy could be a reflection of wind,

waves, or currents present. This is a particularly important

consideration in a review of fishing gear effects since it

indicates the natural disturbance regime of a habitat. The

amount and type of natural disturbance are in turn an

indication of the habitat’s resistance to, and recoverability

from, disturbance by fishing gear. Although this work

appears to be complete in its description of habitat types,

unfortunately, the distributions of many of the habitats are

unknown.

Demersal fish assemblages for the GOM and Georges

Bank were part of broadscale geographic investigations

conducted by Gabriel (1992) and Mahon et al. (1998). Both

of these studies and a more limited study by Overholtz and

Tyler (1985) found assemblages that were consistent over

space and time in this region. In her analysis, Gabriel (1992)

found that the most persistent feature over time in

assemblage structure from Nova Scotia to Cape Hatteras

was the boundary separating assemblages between the

GOM and Georges Bank, which occurred at approximately

the 100-m isobath on northern Georges Bank. Overholtz

and Tyler (1985) identified five assemblages for this region

(Table 2.2). The GOM deep assemblage included a number

of species found in other assemblages, with the exception

of American plaice and witch flounder, which were unique

to this assemblage. Gabriel’s approach did not allow

species to co-occur in assemblages, and classified these

two species as unique to the deepwater GOM - Georges

Bank assemblage. Results of these two studies are

compared in Table 2.2. Auster et al. (2001) went a step

further and related species clusters on Stellwagen Bank to

different substrate types in an attempt to use fish

distribution as a proxy for seafloor habitat distribution.

They found significant associations for 12 of 20 species,

including American plaice (fine substrate) and haddock

(coarse substrate). Species clusters and associated

substrate types are given in Table 2.3.

Georges Bank

Physical Features

Georges Bank is a shallow (3-150 m depth), elongate

(161-km wide by 322-km long) extension of the continental

shelf that was formed by the Wisconsinian glacial episode.

It is characterized by a steep slope on its northern edge and

a broad, flat, gently sloping southern flank. The Great

South Channel lies to the west. Natural processes continue

to erode and rework the sediments on Georges Bank. It is

anticipated that erosion and reworking of sediments will

reduce the amount of sand available to the sand sheets,

and cause an overall coarsening of the bottom sediments

(Valentine and Lough 1991).

Glacial retreat during the late Pleistocene deposited

the bottom sediments currently observed on the eastern

section of Georges Bank, and the sediments have been

continuously reworked and redistributed by the action of

rising sea level, and by tidal, storm, and other currents

(Figure 2.6). The strong, erosive currents affect the

character of the biological community. Bottom topography

on eastern Georges Bank is characterized by linear ridges in

the western shoal areas; a relatively smooth, gently

dipping seafloor on the deeper, easternmost part; a highly

energetic peak in the north with sand ridges up to 30 m high

and extensive gravel pavement; and steeper and smoother

topography incised by submarine canyons on the

southeastern margin (see the “Continental Slope” section

for more on canyons). The interaction of several

environmental factors, including availability and type of

sediment, current speed and direction, and bottom

topography, has formed seven sedimentary provinces on

eastern Georges Bank (Valentine and Lough 1991) which

are described in Table 2.4 and depicted in Figure 2.6. The

gravel-sand mixture is usually a transition zone between

coarse gravel and finer sediments.

The central region of the bank is shallow, and the

bottom is characterized by shoals and troughs, with sand

dunes superimposed upon them. The two most prominent

elevations on the ridge and trough area are Cultivator and

Georges Shoals. This shoal and trough area is a region of

strong currents. The dunes migrate at variable rates, and

the ridges may also move. In an area that lies between the

central part and Northeast Peak, Almeida et al. (2000)

identified high-energy areas between 35 and 65 m deep

where sand is transported on a daily basis by tidal currents,

and a low-energy area >65 m deep that is affected only by

storm currents.

The area west of the Great South Channel, known as

Nantucket Shoals (Figure 2.2), is similar in nature to the

central region of the bank. Currents in these areas are

strongest where water depth is shallower than 50 m. This

type of traveling dune-and-swale morphology is also

found in the MAB, and further described in that section of

this document. The Great South Channel separates the

main part of Georges Bank from Nantucket Shoals.

Sediments in this region include gravel pavement and

mounds, some scattered boulders, sand with storm

generated ripples, and scattered shell and mussel beds.

Tidal and storm currents range from moderate to strong,

depending upon location and storm activity (pers. comm.;

Page C. Valentine, U.S. Geological Survey, Woods Hole, MA).

Oceanographic frontal systems separate water masses

of the GOM and Georges Bank from oceanic waters south
Page 8

of the bank. These water masses differ in temperature,

salinity, nutrient concentration, and planktonic communities, which influence productivity and may influence fish

abundance and distribution. Currents on Georges Bank

include a weak, persistent clockwise gyre around the bank,

a strong semidiurnal tidal flow predominantly northwest

and southeast, and very strong, intermittent storm-induced

currents, which all can occur simultaneously (Figure 2.4).

Tidal currents over the shallow top of Georges Bank can be

very strong, and keep the waters over the bank well mixed

vertically. This results in a tidal front that separates the

cool waters of the well-mixed shallows of the central bank

from the warmer, seasonally stratified shelf waters on the

seaward and shoreward sides of the bank. The clockwise

gyre is instrumental in distribution of the planktonic

community, including larval fish. For example, Lough and

Potter (1993) describe passive drift of Atlantic cod and

haddock eggs and larvae in a southwest residual pattern

around Georges Bank. Larval concentrations are found at

varying depths along the southern edge between 60 and

100 m.

Benthic Biological Features

Amphipod crustaceans (49%) and annelid worms

(28%) numerically dominated the contents of 211 sediment

samples collected on Georges Bank during 1956-1965

(Theroux and Wigley 1998). Biomass was dominated by

sand dollars (50%) and bivalve mollusks (33%). Theroux

and Grosslein (1987) utilized the same database to identify

four invertebrate assemblages: Western Basin, Northeast

Peak, central Georges Bank, and southern Georges Bank.

(See the last section of this chapter for more information on

benthic invertebrate communities in New England.) They

noted that it is impossible to define discrete boundaries

between assemblages because of the considerable

intergrading that occurs between adjacent assemblages;

however, the assemblages are distinguishable. Their

assemblages are associated with those identified by

Valentine and Lough (1991) in Table 2.4.

The Western Basin assemblage (Theroux and

Grosslein 1987) is found in the upper Great South Channel

region at the northwestern corner of the bank, in

comparatively deep water (150-200 m) with relatively slow

currents and fine bottom sediments of silt, clay, and muddy

sand. The fauna is comprised mainly of small burrowing

detritivores and deposit feeders, and carnivorous scavengers. Representative organisms include bivalve mollusks

(Thyasira flexuosa, [En]ucula tenuis, and Musculus

discors), annelids (Nephtys incisa, Paramphinome

pulchella, Onuphis opalina, and Sternaspis scutata), the

brittle star Ophiura sarsi, the amphipod Haploops

tubicola, and the red deepsea crab ([Chaceon]

quinquedens). Valentine and Lough (1991) did not identify

a comparable assemblage; however, this assemblage is

geographically located adjacent to Assemblage 5 as

described by Watling (1998) (Table 2.1; Figure 2.5)

The Northeast Peak assemblage is found along the

Northern Edge and Northeast Peak, which varies in depth

and current strength, and includes coarse sediment

consisting mainly of gravel and coarse sand with

interspersed boulders, cobbles, and pebbles. The fauna

tends to be sessile (coelenterates, brachiopods, barnacles,

and tubiferous annelids) or free-living (brittle stars,

crustaceans, and polychaetes), with a characteristic

absence of burrowing forms. Representative organisms

include amphipods (Acanthonotozoma serratum and Tiron

spiniferum), the isopod Rocinela americana, the barnacle

Balanus hameri, annelids (Harmothoe imbricata, Eunice

pennata, Nothria conchylega, and Glycera capitata), the

sea scallop Placopecten magellanicus, brittle stars

(Ophiacantha bidentata and Ophiopholis aculeata), and

soft corals (Primnoa resedaeformis and Paragorgia

arborea).

The Central Georges Bank assemblage occupies the

greatest area, including the central and northern portions

of the bank in depths <100 m. Medium-grained shifting

sands predominate this dynamic area of strong currents.

Organisms tend to be small to moderately large with

burrowing or motile habits. Sand dollars (Echinarachnius

parma) are most characteristic of this assemblage. Other

representative species include mysids (Neomysis americana

and Mysidopsis bigelowi), the isopod Chiridotea tuftsi,

the cumacean Leptocuma minor, the amphipod

Protohaustorius wigleyi, annelids (Sthenelais limicola,

Goniadella gracilis, and Scalibregma inflatum), gastropods ([Euspira] heros and Nassarius trivittatus), the

starfish Asterias vulgaris, the shrimp Crangon

septemspinosa, and the crab Cancer irroratus.

The Southern Georges Bank assemblage is found on

the southern and southwestern flanks at depths from 80 to

200 m, where fine-grained sands and moderate currents

predominate. Many southern species exist here at the

northern limits of their range. The dominant fauna includes

amphipods, copepods, euphausiids, and the starfish genus

Astropecten. Representative organisms include amphipods (Ampelisca compressa, Erichthonius rubricornis,

and Synchelidium americanum), the cumacean Diastylis

quadrispinosa, annelids (Aglaophamus circinata, Nephtys

squamosa, and Apistobranchus tullbergi), crabs

(Euprognatha rastellifera and Catapagurus sharreri) and

the shrimp Munida iris.

Along with high levels of primary productivity,

Georges Bank has been historically characterized by high

levels of fish production. Several studies have attempted

to identify demersal fish assemblages over large spatial

scales. Overholtz and Tyler (1985) found five depth-related

demersal fish assemblages for Georges Bank and the GOM

that were persistent temporally and spatially (Table 2.2).

Depth and salinity were identified as major physical

influences explaining assemblage structure. Gabriel (1992)
Page 9

identified six assemblages which are compared with the

results of Overholtz and Tyler (1985) in Table 2.2. Mahon et

al. (1998) found similar results.

Mid-Atlantic Bight

Physical Features

The MAB includes the shelf and slope waters from

Georges Bank south to Cape Hatteras, and east to the Gulf

Stream (Figure 2.1). Like the rest of the continental shelf,

the topography of the MAB was shaped largely by sea -

level fluctuations caused by past ice ages. The shelf’s

basic morphology and sediments derive from the retreat of

the last ice sheet, and the subsequent rise in sea level.

Since that time, currents and waves have modified this

basic structure.

Shelf and slope waters of the MAB have a slow

southwestward flow that is occasionally interrupted by

warm-core rings or meanders from the Gulf Stream. On

average, shelf water moves parallel to bathymetry isobars

at speeds of 5-10 cm/s at the surface and 2 cm/s or less at

the bottom. Storm events can cause much more energetic

variations in flow. Tidal currents on the inner shelf have a

higher flow rate of 20 cm/s that increases to 100 cm/s near

inlets.

Slope water tends to be warmer than shelf water

because of its proximity to the Gulf Stream, and tends to be

more saline. The abrupt gradient where these two water

masses meet is called the shelf-slope front. This front is

usually located at the edge of the shelf and touches bottom

at about 75-100 m depth of water, and then slopes up to the

east toward the surface. It reaches surface waters

approximately 25-55 km further offshore. The position of

the front is highly variable, and can be influenced by many

physical factors. Vertical structure of temperature and

salinity within the front can develop complex patterns

because of the interleaving of shelf and slope waters; e.g.,

cold shelf waters can protrude offshore, or warmer slope

water can intrude up onto the shelf.

The seasonal effects of warming and cooling increase

in shallower, nearshore waters. Stratification of the water

column occurs over the shelf and the top layer of slope

water during the spring-summer and is usually established

by early June. Fall mixing results in homogenous shelf and

upper slope waters by October in most years. A permanent

thermocline exists in slope waters from 200 to 600 m deep.

Temperatures decrease at the rate of about 0.02°C/m, and

remain relatively constant except for occasional incursions

of Gulf Stream eddies or meanders. Below 600 m,

temperature declines, and usually averages about 2.2°C at

4000 m. A warm, mixed layer approximately 40-m thick

resides above the permanent thermocline.

The “cold pool” is an annual phenomenon particularly

important to the MAB. It stretches from the GOM along the

outer edge of Georges Bank and then southwest to Cape

Hatteras. It becomes identifiable with the onset of thermal

stratification in the spring and lasts into early fall until

normal seasonal mixing occurs. It usually exists along the

bottom between the 40- and 100-m isobaths, and extends

up into the water column for about 35 m, and to the bottom

of the seasonal thermocline. The cold pool usually

represents about 30% of the volume of shelf water.

Minimum temperatures for the cold pool occur in early

spring and summer, and range from 1.1 to 4.7°C.

The shelf slopes gently from shore out to between 100

and 200 km offshore where it transforms to the slope (100-

200 m of water depth) at the shelf break. In both the MidAtlantic and on Georges Bank, numerous canyons incise

the slope, and some cut up onto the shelf itself (see the

subsequent “Continental Slope” section). The primary

morphological features of the shelf include shelf valleys

and channels, shoal massifs, scarps, and sand ridges and

swales (Figures 2.7 and 2.8).

Most of these structures are relic except for some sand

ridges and smaller sand-formed features. Shelf valleys and

slope canyons were formed by rivers of glacier outwash

that deposited sediments on the outer shelf edge as they

entered the ocean. Most valleys cut about 10 m into the

shelf, with the exception of the Hudson Shelf Valley that is

about 35 m deep. The valleys were partially filled as the

glacier melted and retreated across the shelf. The glacier

also left behind a lengthy scarp near the shelf break from

Chesapeake Bay north to the eastern end of Long Island

(Figures 2.7 and 2.8). Shoal retreat massifs were produced

by extensive deposition at a cape or estuary mouth.

Massifs were also formed as estuaries retreated across the

shelf.

The sediment type covering most of the shelf in the

MAB is sand, with some relatively small, localized areas of

sand-shell and sand-gravel. On the slope, silty sand, silt,

and clay predominate.

Some sand ridges (Figure 2.7) are more modern in

origin than the shelf’s glaciated morphology. Their

formation is not well understood; however, they appear to

develop from the sediments that erode from the shore face.

They maintain their shape, so it is assumed that they are in

equilibrium with modern current and storm regimes. They

are usually grouped, with heights of about 10 m, lengths of

10-50 km, and spacing of about 2 km. Ridges are usually

oriented at a slight angle towards shore, running in length

from northeast to southwest. The seaward face usually has

the steepest slope. Sand ridges are often covered with

smaller similar forms such as sand waves, megaripples, and

ripples. Swales occur between sand ridges. Since ridges

are higher than the adjacent swales, they are exposed to

more energy from water currents, and experience more

sediment mobility than swales. Ridges tend to contain less

fine sand, silt, and clay, while relatively sheltered swales

contain more of the finer particles. Swales have greater

benthic macrofaunal density, species richness, and

biomass due, in part, to the increased abundance of detrital

food and the physically less rigorous conditions.
Page 10

Sand waves are usually found in patches of 5-10 with

heights of about 2 m, lengths of about 50-100 m, and

spacing of about 1-2 km. Sand waves are primarily found

on the inner shelf, and often observed on sides of sand

ridges. Sand waves may remain intact over several

seasons. Megaripples occur on sand waves or separately

on the inner or central shelf. During the winter storm

season, these megaripples may cover as much as 15% of

the inner shelf. They tend to form in large patches and

usually have lengths of about 3-5 m with heights of about

0.5-1 m. Megaripples tend to survive for less than a season.

They can form during a storm and reshape the upper 50-100

cm of the sediments within a few hours. Ripples are also

found everywhere on the shelf, and appear or disappear

within hours or days, depending upon storms and currents.

Ripples usually have lengths of about 1-150 cm and heights

of a few centimeters.

Sediments are uniformly distributed over the shelf in

this region (see Figure 2.3). A sheet of sand and gravel

varying in thickness from 0 to10 m covers most of the shelf.

The mean bottom flow from the constant southwesterly

current is not fast enough to move sand, so sediment

transport must be episodic. Net sediment movement is in

the same southwesterly direction as the current. The sands

are mostly medium-to-coarse grains, with finer sand in the

Hudson Shelf Valley and on the outer shelf. Mud is rare

over most of the shelf, but is common in the Hudson Shelf

Valley. Occasionally, relic estuarine mud deposits are reexposed in the swales between sand ridges. Fine sediment

content increases rapidly at the shelf break, which is

sometimes called the “mud line,” and sediments are 70-

100% fines on the slope.

The northern portion of the MAB is sometimes

referred to as Southern New England. Most of this area

was discussed under Georges Bank; however, one other

formation of this region deserves note. The “Mud Patch”

is located just southwest of Nantucket Shoals and

southeast of Long Island and Rhode Island (Figure 2.3).

Tidal currents in this area slow significantly, which allows

silts and clays to settle out. The mud is mixed with sand,

and is occasionally resuspended by large storms. This

habitat is an anomaly of the outer continental shelf.

Artificial reefs are another significant Mid-Atlantic

habitat, formed much more recently on the geologic time

scale than other regional habitat types. These localized

areas of hard structure have been formed by shipwrecks,

lost cargoes, disposed solid materials, shoreline jetties and

groins, submerged pipelines, cables, and other materials

(Steimle and Zetlin 2000). While some of materials have

been deposited specifically for use as fish habitat, most

have an alternative primary purpose; however, they have

all become an integral part of the coastal and shelf

ecosystem. It is expected that the increase in these

materials has had an effect on living marine resources and

fisheries, but these effects are not well known. In general,

reefs are important for attachment sites, shelter, and food

for many species, and fish predators such as tunas may be

attracted by prey aggregations, or may be behaviorally

attracted to the reef structure. The overview by Steimle and

Zetlin (2000) used NOAA hydrographic surveys to plot

rocks, wrecks, obstructions, and artificial reefs, which

together were considered a fairly complete list of

nonbiogenic reef habitat in the Mid-Atlantic estuarine and

coastal areas (Figure 2.9).

Benthic Biological Features

Wigley and Theroux (1981) reported on the faunal

composition of 563 bottom grab samples collected in the

MAB during 1956-1965. Amphipod crustaceans and

bivalve mollusks accounted for most of the individuals

(41% and 22%, respectively), whereas mollusks dominated

the biomass (70%). Three broad faunal zones related to

water depth and sediment type were identified by Pratt

(1973). The “sand fauna” zone was defined for sandy

sediments (1% or less silt) that are at least occasionally

disturbed by waves, from shore out to the 50-m depth

(Figure 2.10). The “silty sand fauna” zone occurred

immediately offshore from the sand fauna zone, in stable

sands containing a small amount of silt and organic

material. Silts and clays become predominant at the shelf

break, line the Hudson Shelf Valley, and support the “siltclay fauna.” (See the “Regional Benthic Invertebrate

Communities/Mid-Atlantic Bight” section of this chapter

for more information on benthic invertebrate communities

in the MAB and their relation to depth and sediment type).

Building on Pratt’s work, the Mid-Atlantic shelf was

further divided by Boesch (1979) into seven bathymetric/

morphologic subdivisions based on faunal assemblages

(Table 2.5). Sediments in the region studied (Hudson Shelf

Valley south to Chesapeake Bay) were dominated by sand

with little finer materials. Ridges and swales are important

morphological features in this area. Sediments are coarser

on the ridges, and the swales have greater benthic

macrofaunal density, species richness, and biomass.

Faunal species composition differed between these

features, and Boesch (1979) incorporated this variation in

his subdivisions (Table 2.5). Much overlap of species

distributions was found between depth zones, so the

faunal assemblages represented more of a continuum than

distinct zones.

Demersal fish assemblages were described at a broad

geographic scale for the continental shelf and slope from

Cape Chidley, Labrador, to Cape Hatteras, North Carolina

(Mahon et al. 1998), and from Nova Scotia to Cape Hatteras

(Gabriel 1992). Factors influencing species distribution

included latitude and depth. Results of these studies were

similar to an earlier study confined to the MAB continental

shelf (Colvocoresses and Musick 1984). In this latter

study, there were clear variations in species abundances,

yet the authors demonstrated consistent patterns of

community composition and distribution among demersal

fishes of the Mid-Atlantic shelf. This is especially true for
Page 11

five strongly recurring species associations that varied

slightly from spring to fall (Table 2.6). The boundaries

between fish assemblages generally followed isotherms

and isobaths. The assemblages were largely similar

between the spring and fall collections, with the most

notable change being a northward and shoreward shift in

the temperate group in the spring.

Steimle and Zetlin (2000) described representative

epibenthic/epibiotic, motile epibenthic, and fish species

associated with sparsely scattered reef habitats that

consist mainly of manmade structures (Table 2.7).

Continental Slope

Physical Features

The continental slope extends from the continental

shelf break, at depths between 60-200 m, eastward to a

depth of 2000 m. The width of the slope varies from 10-50

km, with an average gradient of 3-6°; however, local

gradients can be nearly vertical. The base of the slope is

defined by a marked decrease in seafloor gradient where

the continental rise begins.

The morphology of the present continental slope

appears largely to be a result of sedimentary processes that

occurred during the Pleistocene, including, 1) slope

upbuilding and progradation by deltaic sedimentation

principally during sea-level low stands; 2) canyon cutting

by sediment mass movements during and following sealevel low stands; and 3) sediment slumping.

The slope is cut by at least 70 large canyons between

Georges Bank and Cape Hatteras (Figure 2.11), and by

numerous smaller canyons and gullies, many of which may

feed into the larger canyon systems. The New England

Seamount Chain, including Bear, Mytilus, and Balanus

Seamounts, occurs on the slope southeast of Georges

Bank. A smaller chain (Caryn, Knauss, etc.) occurs in the

vicinity in deeper water.

A “mud line” occurs on the slope at a depth of 250-300

m, below which fine silt and clay-size particles predominate

(Figure 2.3). Localized coarse sediments and rock outcrops

are found in and near canyon walls, and occasional

boulders occur on the slope because of glacial rafting.

Sand pockets may also be formed because of downslope

movements.

Gravity-induced, downslope movement is the dominant sedimentary process on the slope, and includes

slumps, slides, debris flows, and turbidity currents, in the

order from thick cohesive movement to relatively

nonviscous flow. Slumps may involve localized, short,

downslope movements by blocks of sediment. However,

turbidity currents can transport sediments thousands of

kilometers.

Submarine canyons are not spaced evenly along the

slope, but tend to decrease in areas of increasing slope

gradient. Canyons are typically “v” shaped in cross

section, and often have steep walls and outcroppings of

bedrock and clay. The canyons are continuous from the

canyon heads to the base of the continental slope. Some

canyons end at the base of the slope, but others continue

as channels onto the continental rise. Larger and more

deeply incised canyons are generally significantly older

than smaller ones, and there is evidence that some older

canyons have experienced several episodes of filling and

re-excavation. Many, if not all, submarine canyons may

first form by mass-wasting processes on the continental

slope, although there is evidence that some canyons were

formed because of fluvial drainage (e.g., Hudson Canyon).

Canyons can alter the physical processes in the

surrounding slope waters. Fluctuations in the velocities of

the surface and internal tides can be large near the heads of

the canyons, leading to enhanced mixing and sediment

transport in the area. Shepard et al. (1979) concluded that

the strong turbidity currents initiated in study canyons

were responsible for enough sediment erosion and

transport to maintain and modify those canyons. Since

surface and internal tides are ubiquitous over the

continental shelf and slope, it can be anticipated that these

fluctuations are important for sedimentation processes in

other canyons as well. In Lydonia Canyon, Butman et al.

(1982) found that the dominant source of low-frequency

current variability was related to passage of warm-core Gulf

Stream rings rather than the atmospheric events that

predominate on the shelf.

The water masses of the Atlantic continental slope and

rise are essentially the same as those of the North American

Basin [defined in Wright and Worthington (1970)].

Worthington (1976) divided the water column of the slope

into three vertical layers: deepwater (colder than 4°C), the

thermocline (4-17°C), and surface water (warmer than 17°C).

In the North American Basin, deepwater accounts for twothirds of all water, the thermocline for about one-quarter,

and surface water the remainder. In the slope water north of

Cape Hatteras, the only warm water occurs in the Gulf

Stream and in seasonally influenced summer waters.

The principal cold water mass in the region is the North

Atlantic Deep Water. North Atlantic Deep Water is

comprised of a mixture of five sources: Antarctic Bottom

Water, Labrador Sea Water, Mediterranean Water,

Denmark Strait Overflow Water, and Iceland-Scotland

Overflow Water. The thermocline represents a straightforward water mass compared with either the deepwater or the

surface water. Nearly 90% of all thermocline water comes

from the water mass called the Western North Atlantic

Water. This water mass is slightly less saline northeast of

Cape Hatteras due to the influx of southward flowing

Labrador Coastal Water. Seasonal variability in slope

waters occurs only in the upper 200 m of the water column.

In the winter months, cold temperatures and storm

activity create a well-mixed layer down to about 100-150 m,

but summer warming creates a seasonal thermocline

overlain by a surface layer of low-density water. The

seasonal thermocline, in combination with reduced storm
Page 12

activity in the summer, inhibits vertical mixing and reduces

the upward transfer of nutrients into the photic zone.

Two currents found on the slope, the Gulf Stream and

Western Boundary Undercurrent, together represent one

of the strongest low-frequency horizontal flow systems in

the world. Both currents have an important influence on

slope waters. Warm- and cold-core rings that spin off the

Gulf Stream are a persistent and ubiquitous feature of the

Northwest Atlantic Ocean. The Western Boundary

Undercurrent flows to the southwest along the lower slope

and continental rise in a stream about 50 km wide. This

boundary current is associated with the spread of North

Atlantic Deep Water, and forms part of the generally

westward flow found in slope water. North of Cape

Hatteras, it crosses under the Gulf Stream in a manner not

yet completely understood.

Shelf and slope waters of the Northeast Region are

intermittently affected by the Gulf Stream. The Gulf Stream

begins in the Gulf of Mexico and flows northeastward at an

approximate rate of 1 m/s (2 knots), transporting warm

waters north along the eastern coast of the United States,

and then east towards the British Isles. Conditions and

flow of the Gulf Stream are highly variable on time scales

ranging from days to seasons. Intrusions from the Gulf

Stream constitute the principal source of variability in slope

waters off the Northeast Continental Shelf.

The location of the Gulf Stream’s shoreward, western

boundary is variable because of meanders and eddies. Gulf

Stream eddies are formed when extended meanders enclose

a parcel of seawater and pinch off. These eddies can be

cyclonic, meaning they rotate counterclockwise and have a

cold core formed by enclosed slope water (cold-core ring),

or anticyclonic, meaning they rotate clockwise and have a

warm core of Sargasso Sea water (warm-core ring). The

rings are shaped like a funnel, wider at the top and narrower

at the bottom, and can have depths of over 2000 m. They

range in approximate size from 150 to 230 km in diameter.

There are 35% more rings and meanders near Georges Bank

than in the Mid-Atlantic region. A net transfer of water on

and off the shelf may result from the interaction of rings and

shelf waters. These warm- or cold-core rings maintain their

identity for several months until they are reabsorbed by the

Gulf Stream. The rings and the Gulf Stream itself have a

great influence over oceanographic conditions all along

the continental shelf.

Benthic Biological Features

Polychaete annelids represent the most important

slope faunal group in terms of numbers of individuals and

species (Wiebe et al. 1987). Ophiuroids (brittle stars) are

considered to be among the most abundant slope

organisms, but this group is comprised of relatively few

species. The taxonomic group with the highest species

diversity is the peracarid crustaceans (which include

amphipods, cumaceans, and isopods). Some species of the

slope are widely distributed, while others appear to be

restricted to particular ocean basins. The ophiuroids and

bivalve mollusks appear to have the broadest distributions,

while the peracarid crustaceans appear to be highly

restricted because they brood their young, and lack a

planktonic stage of development. In general, gastropods

do not appear to be very abundant; however, past studies

are inconclusive since they have not collected enough

individuals for largescale community and population

studies. (See the “Regional Benthic Invertebrate

Communities” section of this chapter for more information

on benthic invertebrate communities on the continental

slope.)

In general, slope-inhabiting benthic organisms are

strongly zoned by depth and/or water temperature,

although these patterns are modified by the presence of

topography, including canyons, channels, and current

zonations (Hecker 1990). Moreover, at depths of <800 m,

the fauna is extremely variable and the relationships

between faunal distribution and substrate, depth, and

geography are less obvious (Wiebe et al. 1987). The fauna

occupying hard surface sediments is not as dense as in

comparable shallow water habitats (Wiebe et al. 1987), but

there is an increase in species diversity from the shelf to the

intermediate depths of the slope. Diversity then declines

again in the deeper waters of the continental rise and plain.

Hecker (1990) identified four megafaunal zones on the

slope of Georges Bank and Southern New England (Table

2.8).

One group of organisms of interest because of the

additional structure they can provide for habitat and their

potential long life span are the alcyonarian soft corals. Soft

corals can be bush or treelike in shape; species found in

this form attach to hard substrates such as rock outcrops or

gravel. These species can range in size from a few

millimeters to several meters, and the trunk diameter of large

specimens can exceed 10 cm. Other alcyonarians found in

this region include sea pens and sea pansies (Order

Pennatulacea), which are found in a wider range of

substrate types. In their survey of Northeast U.S.

Continental Shelf macrobenthic invertebrates, Theroux and

Wigley (1998) found alcyonarians (including the soft

corals Alcyonium sp., Acanella sp., Paragorgia arborea,

and Primnoa reseda, and the sea pens) in limited numbers

in waters deeper than 50 m, and mostly at depths from 200

to 500 m. Alcyonarians were present in each of the

geographic areas identified in the study (Nova Scotia,

GOM, Southern New England Shelf, Georges Slope, and

Southern New England Slope) except Georges Bank.

However, Paragorgia and Primnoa have been reported in

the Northeast Peak region of Georges Bank (Theroux and

Grosslein 1987). Alcyonarians were most abundant by

weight in the GOM, and by number on the Southern New

England Slope (Theroux and Wigley 1998). In this study,

alcyonarians other than sea pens were collected only from

gravel and rocky outcrops. Theroux and Wigley (1998)

also found stony corals (Astrangia danae and Flabellum
Page 13

sp.) in the Northeast Region, but they were uncommon. In

similar work on the Mid-Atlantic shelf, the only

alcyonarians encountered were sea pens (Wigley and

Theroux 1981). The stony coral Astrangia danae was also

found, but its distribution and abundance were not

discussed, and are assumed to be minimal.

As opposed to most slope environments, canyons

may develop a lush epifauna. Hecker et al. (1983) found

faunal differences between the canyons and slope

environments. Hecker and Blechschmidt (1979) suggested

that faunal differences were due at least in part to increased

environmental heterogeneity in the canyons, including

greater substrate variability and nutrient enrichment.

Hecker et al. (1983) found highly patchy faunal

assemblages in the canyons, and also found additional

faunal groups located in the canyons, particularly on hard

substrates, that do not appear to occur in other slope

environments. Canyons are also thought to serve as

nursery areas for a number of species (Cooper et al. 1987;

Hecker 2001). The canyon habitats in Table 2.9 were

classified by Cooper et al. (1987).

Most finfish identified as slope inhabitants on a broad

spatial scale (Colvocoresses and Musick 1984; Overholtz

and Tyler 1985; Gabriel 1992) (Tables 2.2 and 2.6) are

associated with canyon features as well (Cooper et al. 1987)

(Table 2.9). Finfish identified by broad studies that were

not included in Cooper et al. (1987) include offshore hake,

fawn cusk-eel, longfin hake, witch flounder, and armored

searobin. Canyon species (Cooper et al. 1987) that were

not discussed in the broadscale studies include squirrel

hake, conger eel, and tilefish. Cusk and ocean pout were

identified by Cooper et al. (1987) as canyon species, but

classified in other habitats by the broadscale studies.

Coastal and Estuarine Features

Coastal and estuarine features such as salt marshes,

mud flats, rocky intertidal zones, sand beaches, and

submerged aquatic vegetation are critical to inshore and

offshore habitats and fishery resources of the Northeast.

For example, coastal areas and estuaries are important for

nutrient recycling and primary production, and certain

features serve as nursery areas for juvenile stages of

economically important species. Salt marshes are found

extensively throughout the region. Tidal and subtidal mud

and sand flats are general saltmarsh features and also occur

in other estuarine areas. Salt marshes provide nursery and

spawning habitat for many fish and invertebrate species.

Saltmarsh vegetation can also be a large source of organic

material that is important to the biological and chemical

processes of the estuarine and marine environment.

Rocky intertidal zones are high-energy, periodically

submerged environments found in the northern portion of

the Northeast system. Sessile invertebrates and some fish

inhabit rocky intertidal zones. A variety of algae, kelp, and

rockweed are also important habitat features of rocky

shores. Fishery resources may depend on particular

habitat features of the rocky intertidal zone that provide

important levels of refuge and food.

Sandy beaches are most extensive along the Northeast

coast. Different zones of the beach present suitable habitat

conditions for a variety of marine and terrestrial organisms.

For example, the intertidal zone presents suitable habitat

conditions for many invertebrates, and transient fish find

suitable conditions for foraging during high tide. Several

invertebrate and fish species are adapted for living in the

high-energy subtidal zone adjacent to sandy beaches.

REGIONAL BENTHIC INVERTEBRATE

COMMUNITIES

New England

Theroux and Wigley (1998) reported the results of an

extensive, 10-yr benthic sampling program in New England.

A total of 1,076 bottom grab samples were collected during

spring, summer, and fall during 1956-1965 on the

continental shelf and slope in Southern New England,

Georges Bank, and the GOM. Twenty-eight percent of the

samples (303) were collected in the GOM, 20% (211) on

Georges Bank, 32% (344) in Southern New England, and

12% (133) on the slope in Southern New England and on

Georges Bank. Results were summarized according to

major taxonomic groups, principal species, depth ranges,

sediment types, ranges of bottom water temperatures, and

the sediment organic carbon content. Results presented

here are for major taxa by depth range and sediment type.

Detailed information for the individual subregions is not

presented in this document. Distribution and abundance

information for the Mid-Atlantic region is compiled in an

earlier publication (Wigley and Theroux 1981) and is

summarized in the next section of this chapter.

The density and biomass of all taxa exhibited similar

patterns (Figure 2.12). Both were generally higher in

coastal GOM waters, on the southern and eastern areas of

Georges Bank (including the Northeast Peak), on most of

the Southern New England shelf, and south of Long Island.

Density and biomass were lower in deeper water of the

GOM, on the north-central part of Georges Bank, on the

western side of the Great South Channel, on the continental

slope and rise, and in portions of Southern New England.

Very high biomass was reported in Rhode Island coastal

waters, in Cape Cod Bay, and at the southern end of the

Great South Channel. Total biomass (mean wet weight per

square meter) was about twice as high on the Southern

New England shelf and on Georges Bank as in the GOM

and over 10 times higher than on the continental slope.

Echinoderms and mollusks dominated the biomass in the

GOM, on Georges Bank, and in Southern New England.

Crustaceans and annelids dominated the density in

Southern New England and on Georges Bank; annelids and

mollusks dominated in the GOM.
Page 14

Depth Influence

Analysis of faunal composition by major taxonomic

groups in eight different depth ranges reveals a

pronounced decline in density at the shelf break,

particularly between 100-200 m (Figure 2.13). Density

declined very little between 25 and 100 m, and by 60%

between 100 and 200 m. Density continued to decline at

successively greater depths, but very slowly per meter

increase in depth. The relative changes in biomass on the

shelf were more pronounced (Figure 2.14). Biomass

declined by 50% between 25-100 m and by 55% between

100-200 m.

On the shelf (down to 100 m), crustaceans (mostly

amphipods) were numerically the most abundant taxon,

with annelids accounting for 20-29% of the organisms; in

just the 0-24 m depth range, mollusks accounted for 23%.

Bivalve mollusks made up over half the biomass in the 0-24

and 50-99 m depth ranges, and 33% in the 25-49 m range.

Echinoderms (sand dollars and sea urchins) dominated the

biomass in the intermediate depth range (25-49 m) on the

shelf. Between 100 and 499 m, annelids were the most

numerous taxon, but echinoderms dominated the biomass.

Mollusks accounted for 36-46%, and annelids for 12-39%,

of the organisms in deeper water (500-4000 m), with a

diminishing proportion of annelids and an increasing

proportion of “other” organisms. Biomass on the shelf rise

was composed of a variety of taxa.

Sediment Influence

Theroux and Wigley (1998) classified sediments

sampled in the New England region into six categories:

gravel, glacial till, shell, sand, sand-silt, and silt-clay. Four

of these sediment types were well sampled (148-455

samples); shell and till sediments were poorly sampled (6-

22 samples) and will not be included in the discussion that

follows, even though the data are included in Figure 2.15.

Total numbers and biomass were highest in sand and

lowest in silt-clay, with intermediate values in gravel and

sand-silt. Amphipods dominated numerically in gravel

(42%) and sand (56%), but annelids were also numerous

(25-33%). Annelids, crustaceans, and mollusks made up

nearly equal proportions, by number, of the sand-silt

samples, and mollusks and annelids dominated, by number,

the silt-clay samples. Mollusks accounted for 50% of the

biomass in gravel; the remainder was composed primarily

of annelids, crustaceans (mostly barnacles and crabs), sea

anemones, sponges, and tunicates. Bivalve mollusks

accounted for about half (48%) of the biomass in sand, but

echinoids were also important (33%). Bivalve mollusks

were also the dominant taxon in biomass in sand-silt (42%),

but less so in silt-clay (20%) where 50% of the biomass was

composed of echinoderms, mostly sea cucumbers.

Annelids made up 15% and 19% of the biomass in sand-silt

and silt-clay sediments, respectively.

Important Fauna

Theroux and Wigley (1998) described the geographic

distribution of 24 genera and species of benthic

invertebrates in New England that were selected because

of their common occurrence, regional ubiquity, or

distinctive distribution patterns. Information summarizing

the importance of these genera and species as prey for fish

and their sediment associations is given in Table 2.10.

Mid-Atlantic Bight

Wigley and Theroux (1981) reported the results of an

extensive 10-yr benthic sampling program in the MAB, an

area extending from Cape Cod to Cape Hatteras and

including Southern New England (which was also included

in the more recent report by Theroux and Wigley (1998) for

New England). A total of 667 bottom grab samples were

collected during spring, summer, and fall, primarily between

1962 and 1965, on the continental shelf, slope, and rise. A

nearly equal number of samples were collected in each of

three subregions: Southern New England (Cape Cod to

Montauk Point, Long Island), the New York Bight

(Montauk Point to Cape May, New Jersey), and the

Chesapeake Bight (Cape May to Cape Hatteras). Results

were summarized according to major taxonomic groups,

depth ranges, sediment types, ranges of bottom water

temperatures, and the sediment organic carbon content.

Results presented here are for major taxa by depth range

and sediment type. Detailed information for the individual

subregions is not presented in this document.

Over the entire MAB, arthropods (mostly amphipods)

numerically made up 46% of the benthic fauna, followed by

mollusks (25%, mostly bivalves) and annelids (21%).

Biomass was dominated by mollusks (71%).

Among subregions, there was some variation in the

densities of the major taxa; the proportion of amphipods

diminished from north to south, while the proportion of

mollusks increased. There was no variation in biomass,

though; mollusks dominated the biomass in all three

subregions.

From a geographic perspective, total density generally

declined from shallow inshore areas to deeper areas on the

slope, and from north to south. There were some small

areas of low and high density on the mid-shelf in the

southern half of the region, and there was a large area of

high density in Southern New England and south of Long

Island (Figure 2.16). Biomass (mostly mollusks) was more

variable, with areas of high and low biomass scattered

throughout the region (Figure 2.17).
Page 15

Depth Influence

Total density was about the same in the shallowest

depth interval (0-24 m) as it was at 50-99 m, and then

declined by 61% between 50 and 200 m, and continued to

decline, although not as rapidly (per unit change in depth)

in deeper water (Figure 2.18). Mollusks (mostly bivalves)

were numerically more abundant in the shallowest depth

range (0-24 m), and amphipods in the next two deeper shelf

depth ranges (25-49 and 50-99 m). The density of

amphipods declined dramatically in the deeper water (100-

199 m), as did annelids but less so, while the density of

mollusks remained the same and that of echinoderms

(brittle stars) increased. On a percentage basis, annelids,

mollusks, and echinoderms made up nearly equal

proportions, by number, of the benthic fauna between 100

and 200 m. Annelids were the most numerous taxon

between 200 and 500 m, as were mollusks in deeper water.

Total biomass (mean grams per square meter) was

lower in all depth ranges in the MAB than in New England,

and declined by about 78% between shallow water (0-24 m)

and the 100-199 m depth interval (Figure 2.18). The rate of

decline generally diminished in deeper water. The high

biomass in the 0-24 m depth range was due to the

prevalence of bivalve mollusks, which were not nearly as

abundant in deeper shelf waters, but still accounted for 58-

65% of the biomass in depths <100 m. A variety of

echinoderms (sand dollars, sea cucumbers, brittle stars,

and starfish) accounted for 45% of the biomass between

100 and 200 m, where bivalve mollusks still made up 21%

and sea anemones 19%. Sand dollars, sea cucumbers, and

brittle stars (with annelids) still dominated the biomass

between 200 and 500 m, and annelids were the taxon which

accounted for most of the biomass between 500 and 1000 m.

Echinoderms and echiurid worms dominated the biomass

of the sparse fauna of the continental rise.

Sediment Influence

Sediments in the MAB were classified into eight

categories: gravel, sand-gravel, shell, sand-shell, sand,

silty sand, silt, and clay. Figure 2.19 was derived for this

document from data given in Wigley and Theroux (1981),

and excludes the results for two poorly sampled sediment

types: gravel and shell. Sample sizes for the other six

groups ranged from 18 (sand-gravel) to 285 (sand). Total

density was highest in sand-gravel and sand-shell,

moderately high in sand and silty sand, and low in silt and

clay. Total biomass was highest in silty sand, moderate in

sand-gravel and sand, and low in sand-shell, silt, and clay.

Amphipods dominated the sand-gravel and sand

sediment types numerically, while mollusks were the most

numerous taxon in the other four substrates. Almost all of

the mollusks in sand-gravel, sand-shell, and sand were

bivalves, but gastropods were also important in silty sand.

Annelids, hydroids, and bryozoans were numerically

important components of the sand-gravel fauna. Annelids

were also common in sand, silty sand, sand-gravel, silt, and

clay substrates. Bivalve mollusks dominated the biomass

in all six substrates. Other taxa with abundant biomass

were barnacles in sand-gravel, and sand dollars in sandshell and sand.

Important Fauna

Wigley and Theroux (1981) described the geographic

distribution of 24 genera and species of benthic

invertebrates in the MAB that were selected because of

their common occurrence or distinctive distribution

patterns. Ten of them were also described in the New

England region (see earlier): they are the annelids

Sternaspis scutata and Scalibregma inflatum, the

mollusks Arctica islandica, Cerastoderma pinnulatum,

and Cyclocardia borealis, the arthropods Leptocheirus

pinguis, Cirolana spp., Crangon septemspinosa, and

Pagurus spp., and the echinoderm Echinarachnius parma.

Information summarizing the habitat associations of the

other 14 genera and species is given in Table 2.11.
Page 16

Table 2.1. Gulf of Maine benthic assemblages as identified by Watling (1998). (Geographical distribution of 

assemblages is shown in Figure 2.4.)

Benthic

Assemblage Benthic Community Description

1 Comprises all sandy offshore banks, most prominently Jeffreys Ledge, Fippennies Ledge, and Platts 

Bank; depth on top of banks ~70 m; substrate usually coarse sand with some gravel; fauna 

characteristically sand dwellers with an abundant interstitial component 

2 Comprises the rocky offshore ledges, such as Cashes Ledge, Sigsbee Ridge, and Three Dory Ridge; 

substrate either rock ridge outcrop or very large boulders, often with covering of very fine sediment; 

fauna predominantly sponges, tunicates, bryozoans, hydroids, and other hard-bottom dwellers; 

overlying water usually cold MIW 

3 Probably extends all along coast of GOM in water depths <60 m; bottom waters warm in summer 

and cold in winter; fauna rich and diverse, primarily polychaetes and crustaceans, probably consists 

of several (sub-) assemblages due to heterogeneity of substrate and water conditions near shore and 

at mouths of bays 

4 Extends over soft bottom at depths of 60-140 m, well within the cold MIW; bottom sediments 

primarily fine muds; fauna dominated by polychaetes, shrimp, and cerianthid anemones 

5 Mixed assemblage comprising elements from the coldwater fauna as well as a few deeper water 

species with broader temperature tolerances; overlying water often a mixture of MIW and MBW, 

but generally colder than 7C most of year; fauna sparse, diversity low, dominated by a few 

polychaetes, with brittle stars, sea pens, shrimp, and cerianthids also present 

6 Comprises fauna of deep basins; bottom sediments generally very fine muds, but may have a gravel 

component in offshore morainal regions; overlying water usually 7-8C, with little variation; fauna 

shows some bathyal affinities but densities are not high, dominated by brittle stars and sea pens, and 

sporadically by a tube-making amphipod 

7 True upper slope fauna that extends into the Northeast Channel; water temperatures are always >8C 

and salinities are at least 35 ppt; sediments may be either fine muds or a mixture of mud and gravel 
Page 17

Table 2.2. Comparison of two studies of demersal fish assemblages of Georges Bank and Gulf of Maine. (Species 

associated with the comparable habitats of both studies are listed opposite each other in bold type.)

Overholtz and Tyler (1985) Gabriel (1992)

Assemblage Species Species Assemblage

Slope and 

Canyon 

Offshore hake

Blackbelly rosefish

Gulf Stream flounder 

Fourspot flounder, goosefish, 

silver hake, white hake, red hake 

Offshore hake

Blackbelly rosefish

Gulf Stream flounder 

Fawn cusk-eel, longfin 

hake, armored sea robin 

Deepwater 

Intermediate Silver hake

Red hake 

Goosefish

Atlantic cod, haddock, ocean pout, 

yellowtail flounder, winter skate, 

little skate, sea raven, 

longhorn sculpin 

Silver hake

Red hake 

Goosefish

Northern shortfin squid, 

spiny dogfish, cusk 

Combination of Deepwater Gulf 

of Maine - Georges Bank and 

Gulf of Maine - Georges Bank 

Transition 

Shallow Atlantic cod

Haddock

Pollock

Silver hake 

White hake 

Red hake 

Goosefish 

Ocean pout 

Yellowtail flounder 

Windowpane

Winter flounder 

Winter skate

Little skate 

Longhorn sculpin

Summer flounder 

Sea raven, sand lance 

Atlantic cod

Haddock

Pollock

Yellowtail flounder 

Windowpane

Winter flounder 

Winter skate

Little skate 

Longhorn sculpin

Gulf of Maine - Georges Bank 

Transition Zone 

(see below also)

Shallow Water Georges BankSouthern New England 

Gulf of MaineDeep 

White hake 

American plaice

Witch flounder

Thorny skate 

Silver hake, Atlantic cod, haddock, 

cusk, Atlantic wolffish 

White hake 

American plaice

Witch flounder

Thorny skate 

Redfish 

Deepwater Gulf of Maine - 

Georges Bank 

Northeast Peak Atlantic cod

Haddock

Pollock

Ocean pout, winter flounder, white 

hake, thorny skate, 

longhorn sculpin 

Atlantic cod

Haddock

Pollock

Gulf of Maine - Georges Bank 

Transition Zone 

(see above also)
Page 18

Table 2.3. Substrate associations with five finfish aggregations on Stellwagen Bank, Gulf of Maine. (Numerical data 

are mean number of fish per research vessel survey tow for 10 dominant species in each aggregation 

(Auster et al 2001).)

SUBSTRATE TYPE 

Coarse Wide Range Fine

Species Mean Species Mean Species Mean 

Northern sand lance 

Atlantic herring 

Spiny dogfish 

Atlantic cod 

Longhorn sculpin 

American plaice 

Haddock 

Yellowtail flounder 

Silver hake 

Ocean pout 

No. tows = 83 

1172.0 

72.2 

38.4 

37.4 

29.7 

28.0 

25.7 

20.2 

7.5 

9.0 

American plaice 

Northern sand lance 

Atlantic herring 

Silver hake 

Acadian redfish 

Atlantic cod 

Longhorn sculpin 

Haddock 

Pollock 

Red hake 

No. tows = 159 

63.3 

53.0 

28.5 

22.4 

16.0 

14.0 

9.5 

9.1 

7.9 

6.2 

American plaice 

Acadian redfish 

Silver hake 

Atlantic herring 

Red hake 

Witch flounder 

Atlantic cod 

Haddock 

Longhorn sculpin 

Daubed shanney 

No. tows = 66 

152.0 

31.3 

29.5 

28.0 

26.1 

23.8 

13.1 

12.7 

12.5 

11.4 

Haddock 

Atlantic cod 

American plaice 

Silver hake 

Longhorn sculpin 

Yellowtail flounder 

Spiny dogfish 

Acadian redfish 

Ocean pout 

Alewife 

No. tows = 60 

13.1 

7.3 

5.3 

3.3 

2.0 

1.9 

1.6 

1.6 

1.3 

1.1 

 Silver hake 

American plaice 

Atlantic mackerel 

Pollock 

Alewife 

Atlantic herring 

Atlantic cod 

Longhorn sculpin 

Red hake 

Haddock 

No. tows = 20 

275.0 

97.1 

42.0 

41.1 

37.2 

32.0 

18.1 

16.8 

15.2 

13.2 
Page 19

Table 2.4. Sedimentary provinces and associated benthic landscapes of Georges Bank. (Provinces as defined by 

Valentine et al. (1993) and Valentine and Lough (1991) with additional information from Page C. 

Valentine (pers. comm., U.S. Geological Survey, Woods Hole, MA). Benthic assemblages as assigned 

by Theroux and Grosslein (1987). See text for further discussion on benthic assemblages.)

Sedimentary Province 

(province no.)

Depth

Range (m) Description Benthic

Assemblage

Northern Edge / 

Northeast Peak (1) 40-200 

Dominated by gravel with portions of sand, common 

boulder areas, and tightly packed pebbles; bryozoa, 

hydrozoa, anemones, and calcareous worm tubes are 

abundant in areas of boulders; strong tidal and storm 

currents 

Northeast 

Peak 

Northern Slope and 

Northeast Channel (2) 200-240 

Variable sediment type (gravel, gravel-sand, and sand) 

and scattered bedforms; this is a transition zone between 

the northern edge and southern slope; strong tidal and 

storm currents 

Northeast 

Peak 

North /Central Shelf (3) 60-120 

Highly variable sediment types (ranging from gravel to 

sand) with rippled sand, large bedforms, and patchy gravel 

lag deposits; minimal epifauna on gravel due to sand 

movement; epifauna in sand areas includes amphipods, 

sand dollars, and burrowing anemones 

Central 

Georges 

Central and Southwestern 

Shelf - shoal ridges (4) 10-80 

Dominated by sand (fine and medium grain) with large 

sand ridges, dunes, waves, and ripples; small bedforms in 

southern part; minimal epifauna on gravel due to sand 

movement; epifauna in sand areas includes amphipods, 

sand dollars, and burrowing anemones 

Central 

Georges 

Central and Southwestern 

Shelf - shoal troughs (5) 40-60 

Gravel (including gravel lag) and gravel-sand between 

large sand ridges; patchy large bedforms, strong currents; 

minimal epifauna on gravel due to sand movement; 

epifauna in sand areas includes amphipods, sand dollars, 

and burrowing anemones 

Central 

Georges 

Southeastern Shelf (6) 80-200 

Rippled gravel-sand (medium- and fine-grained sand) with 

patchy large bedforms and gravel lag; weaker currents; 

ripples are formed by intermittent storm currents; 

epifauna includes sponges attached to shell fragments and 

amphipods 

Southern 

Georges 

Southeastern Slope (7) 400-2000 

Dominated by silt and clay with portions of sand (medium 

and fine), with rippled sand on shallow slopes and smooth 

silt-sand deeper 

None 
Page 20

Table 2.5. Mid-Atlantic habitat types (as described by Pratt (1973) and Boesch (1979)), with characteristic 

macrofauna (as identified in Boesch (1979)) 

Habitat Type Description

[after Boesch

(1979)]

Depth

(m)

Characterization

(Pratt (1973) faunal zone) Characteristic Benthic Macrofauna

Inner shelf 0-30 

Coarse sands with finer 

sands off MD and VA (sand 

zone) 

Polychaetes: Polygordius, Goniadella, and 

Spiophanes

Central shelf 30-50 (sand zone) Polychaetes: Spiophanes and Goniadella

Amphipod: Pseudunciola

Central and inner 

shelf swales 0-50 Occurs in swales between 

sand ridges (sand zone) 

Polychaetes: Spiophanes, Lumbrineris, and 

Polygordius

Outer shelf 50-100 (silty sand zone) Amphipods: Ampelisca vadorum and Erichthonius

Polychaetes: Spiophanes

Outer shelf swales 50-100 Occurs in swales between 

sand ridges (silty sand zone) 

Amphipods: Ampelisca agassizi, Unciola, and

Erichthonius

Shelf break 100-200 (silt-clay zone) Not given 

Continental slope >200 (none) Not given 

Table 2.6. Major recurrent demersal finfish assemblages of the Mid-Atlantic Bight during spring and fall (as 

determined by Colvocoresses and Musick (1984)) 

Species Assemblage Season Boreal Warm Temperate Inner Shelf Outer Shelf Slope

Spring Atlantic cod 

Little skate 

Sea raven 

Goosefish 

Winter flounder 

Longhorn sculpin 

Ocean pout 

Silver hake 

Red hake 

White hake 

Spiny dogfish 

Black sea bass 

Summer flounder 

Butterfish 

Scup 

Spotted hake 

Northern searobin 

Windowpane Fourspot flounder Shortnose greeneye 

Offshore hake 

Blackbelly rosefish 

White hake 

Fall White hake 

Silver hake 

Red hake 

Goosefish 

Longhorn sculpin 

Winter flounder 

Yellowtail flounder 

Witch flounder 

Little skate 

Spiny dogfish 

Black sea bass 

Summer flounder 

Butterfish 

Scup 

Spotted hake 

Northern searobin 

Smooth dogfish 

Windowpane Fourspot flounder 

Fawn cusk eel 

Gulf Stream flounder 

Shortnose greeneye 

Offshore hake 

Blackbelly rosefish 

White hake 

Witch flounder 
Page 21

Table 2.7. Mid-Atlantic reef types, location, and representative flora and fauna (as described in Steimle and Zetlin 

(2000))

Representative Flora and Fauna 

Location (Type) Epibenthic/Epibiotic Motile Epibenthic 

Invertebrates Fish

Estuarine (oyster reefs, 

blue mussel beds, other 

hard surfaces, semi-hard 

clay, and Spartina peat 

reefs) 

Eastern oyster, barnacles, 

ribbed mussel, blue 

mussel, algae, sponges, 

tube worms, anemones, 

hydroids, bryozoans, 

common Atlantic slipper 

snail, jingleshell (Anomia

sp.), northern stone coral, 

sea whips, tunicates, 

caprellid amphipods, and 

wood borers 

Xanthid crabs, blue crab, 

Atlantic rock crabs, portly 

spider crab, juvenile 

American lobster, and sea 

stars 

Gobies, spot, striped bass, 

black sea bass, white 

perch, oyster toadfish, 

scup, black drum, Atlantic 

croaker, spot, sheepshead 

porgy, pinfish, juvenile 

and adult tautog, pinfish, 

northern puffer, cunner, 

sculpins, juvenile and 

adult Atlantic cod, rock 

gunnel, conger eel, 

American eel, red hake, 

ocean pout, white hake, 

and juvenile pollock 

Coastal (exposed rock/soft 

marl, harder rock, wrecks 

and artificial reefs, kelp, 

and other materials) 

Boring mollusks 

(piddocks), red algae, 

sponges, anemones, 

hydroids, northern stone 

coral, soft coral, sea whips, 

barnacles, blue mussel, 

northern horse mussel, 

bryozoans, skeleton and 

tubiculous amphipods, 

polychaetes, jingle shell, 

and sea stars 

American lobster, Jonah 

crab, Atlantic rock crab, 

portly spider crab, sea 

stars, urchins, and squid 

egg clusters 

Black sea bass, pinfish, 

scup, cunner, red hake, 

gray triggerfish, black 

grouper, smooth dogfish, 

summer flounder, scad, 

bluefish, amberjack, 

Atlantic cod, tautog, ocean 

pout, conger eel, sea raven, 

rock gunnel, and radiated 

shanny 

Shelf (rocks and boulders, 

wrecks and artificial reefs, 

and other solid substrates) 

Boring mollusks 

(piddocks), red algae, 

sponges, anemones, 

hydroids, stone coral, soft 

coral, sea whips, barnacles, 

blue mussel, northern 

horse mussel, bryozoans, 

amphipods, and 

polychaetes 

American lobster, Jonah 

crabs, Atlantic rock crab, 

portly spider crabs, sea 

stars, urchins, and squid 

egg clusters (with addition 

of some deepwater taxa at 

shelf edge) 

Black sea bass, scup, 

tautog, cunner, gag, 

sheepshead, porgy, round 

herring, sardines, 

amberjack, Atlantic 

spadefish, gray triggerfish, 

mackerels, small tunas, 

spottail pinfish, tautog, 

Atlantic cod, ocean pout, 

red hake, conger eel, 

cunner, sea raven, rock 

gunnel, pollock, and white 

hake 

Outer shelf (reefs and clay 

burrows including “pueblo 

village community”) 

 Tilefish, white hake, and 

conger eel 
Page 22

Table 2.8. Faunal zones of the continental slope of Georges Bank and Southern New England (from Hecker (1990))

Zone Approximate

Depth (m) 

Gradient Current Fauna

Upper slope 300-700 Low Strong Dense filter feeders: Scleratinians 

(Dasmosmilia lymani, Flabellum alabastrum), 

and quill worm (Hyalinoecia sp.) 

Upper middle slope 500-1300 High Moderate Sparse scavengers: red deepsea crab (Chaceon

quinqueidens), northern cutthroat eel, common 

grenadier (Nezumia), alcyonarians (Acanella

arbuscula and Eunephthya florida) in areas of 

hard substrate 

Lower middle 

slope/transition 

1200-1700 High Moderate Sparse suspension feeders: cerianthids and sea 

pen (Distichoptilum gracile) 

Lower slope >1600 Low Strong Dense suspension and deposit feeders: ophiurid 

(Ophiomusium lymani), cerianthids, and sea 

pens 

Table 2.9. Habitat types for the canyons of Georges Bank, including characteristic fauna. (Faunal characterization is 

from Cooper et al. (1987) and is for depths <230 m only.)

Habitat

Type Geologic Description Canyon

Locations Most Commonly Observed Fauna

I Sand or semiconsolidated silt substrate 

(claylike consistency) with <5% 

overlay of gravel. Relatively 

featureless except for conical sediment 

mounds 

Walls and 

axis 

Cerianthid, pandalid shrimp, white colonial 

anemone, Jonah crab, starfishes, portunid crab, 

greeneye, brittle stars, mosaic worm, red hake, 

fourspot flounder, shellless hermit crab, silver 

hake, and Gulf Stream flounder 

II Sand or semiconsolidated silt substrate 

(claylike consistency) with >5% 

overlay of gravel. Relatively 

featureless 

Walls Cerianthids, galatheid crab, squirrel hake, white 

colonial anemone, Jonah crab, silver hake, sea 

stars, ocean pout, brittle stars, shell-less hermit 

crab, and greeneye 

III Sand or semiconsolidated silt (claylike 

consistency) overlain by siltstone 

outcrops and talus up to boulder size. 

Featured bottom with erosion by 

animals and scouring 

Walls White colonial anemone, pandalid shrimp, 

cleaner shrimp, rock anemone, white hake, sea 

stars, ocean pout, conger eel, brittle stars, Jonah 

crab, American lobster, blackbelly rosefish, 

galatheid crab, mosaic worm, and tilefish 

IV Consolidated silt substrate, heavily 

burrowed/excavated. Slope generally 

>5o and <50o. Termed “pueblo 

village” habitat 

Walls Sea stars, blackbelly rosefish, Jonah crab, 

American lobster, white hake, cusk, ocean pout, 

cleaner shrimp, conger eel, tilefish, galatheid 

crab, and shell-less hermit crab 

V Sand dune substrate Axis Sea stars, white hake, Jonah crab, and goosefish 
Page 23

Table 2.10 Habitat associations, and importance as prey for fish, of 24 select genera and species of benthic invertebrates in New

England. (Source: Theroux and Wigley (1998).)

Phylum Genus/Species Description

Annelida Aphrodita hastata Polychaete often found in Atlantic cod, haddock, and red hake stomachs;

commonly inhabits mud bottoms, or mixed bottoms with high mud

content

Scalibregma inflatum Polychaete that is an important food source for many demersal fish;

inhabits silty sand substrates

Sternaspis scutata Burrowing polychaete eaten by winter flounder; commonly inhabits silty

sediments

Mollusca Arctica islandica

(ocean quahog)

Small- to medium-sized individuals preyed upon by Atlantic cod; usually

inhabits muddy sand bottoms, very abundant in some localities on the

continental shelf such as the southern part of Georges Bank

Astarte undata

(wavy astarte)

Most abundant at mid-shelf depths (50-99 m) in sand and till substrates;

not a major prey item of demersal fishes

Cerastoderma pinnulatum

(northern dwarf cockle)

Infrequently found in fish stomachs; prefers sandy substrates, but is also

found in other types of substrate

Cyclocardia borealis

(northern cyclocardia)

Broadly distributed throughout the region, prefers sand and till substrates;

not common in fish diets

Modiolus modiolus

(northern horsemussel)

Largest and most common mussel offshore of New England, prefers sand

and sand-shell substrates

Placopecten magellanicus

(sea scallop)

Most abundant on coarse sandy bottoms; juveniles eaten by some

demersal fishes, principally haddock and ocean pout

Buccinum spp. Four species of whelk of which B. undatum (waved whelk) is by far the

most common, typically found at mid- to lower shelf depths in sand and

coarser-grained sediments

Neptunea [lyrata] decemcostata

(wrinkle whelk)

Typically inhabits hard bottoms ranging from coarse sand to gravels at

mid- to lower shelf depths

Arthropoda Ampelisca agassizi Tube-dwelling amphipod, the most abundant species of amphipod in the

southwestern half of the region, preferring a sandy substratum; a common

prey item in the diet of many demersal fish

Leptocheirus pinguis Another tube-dwelling amphipod abundant on sandy shelf substrates;

very important prey species for demersal fish

Unciola irrorata Another tube-dwelling amphipod important in sands of Georges Bank; an

important prey species for demersal fish

Crangon septemspinosa

(sevenspine bay shrimp)

Found in sandy sediments in inshore and shelf waters, very abundant in

certain localities; an important prey item for nearly all demersal fishes

Homarus americanus

(American lobster)

Widely distributed from inshore bays to offshore canyons, inhabits a

variety of substrates

Hyas coarctatus

(Arctic lyre crab)

Common throughout the region on muddy and pebbly bottoms

Pagurus spp.

(hermit crabs)

Seven species ubiquitous throughout the region in nearly all substrate

types; preyed upon by demersal fishes

Cirolana spp.

(isopods)

At least three species, common on muddy and sandy bottoms in the GOM

and on Georges Bank

Echinodermata Asterias vulgaris

(northern or purple starfish)

One of the most common species of starfish in the region, normally found

on sandy bottoms; juveniles occasionally found in fish stomachs

Leptasterias spp. Several species of starfish that are common inhabitants on sandy bottoms,

very abundant in certain locations; small specimens occasionally preyed

upon by some species of demersal fish

Echinarachnius parma

(northern sand dollar)

Most abundant member of the urchin family in the New England region,

especially in some locations on Georges Bank, lives on sand; a common

prey item for flounders, haddock, and Atlantic cod

Strongylocentrus droebachiensis

(green sea urchin)

Another ubiquitous echinoid, a hard-bottom dweller; preyed upon by

haddock and American plaice

Ophiura spp.

(brittle stars)

At least three species, widely distributed and occur in most sediment

types; common in diets of haddock and American plaice
Page 24

Table 2.11 Habitat associations of 14 of 24 (see Table 2.10 for information on the other 10) select genera and species of benthic

invertebrates in the Mid-Atlantic Bight. (Source: Wigley and Theroux (1981).)

Phylum Genus/Species Description

Annelida Hyalinoecia tubicola Tube-dwelling polychaete that inhabits the shelf break at depths >200

m

Pogonophora Siboglinum ekmani Tube-dwelling species found in deep water on the continental slope

and rise

Mollusca Thyasira spp.

(cleftclams)

Five species of small bivalves most commonly found in offshore

waters and in fine-grained bottom sediments

Lucinoma blakean[um]

(Blake lucine)

Bivalve most common in outer continental shelf waters

Ensis directus

(razor clam)

Sand-dwelling species found in shallow inshore waters and on the

continental shelf

Polinices spp.

(moon snails)

Two species found on sandy sediments on the continental shelf

Alvania spp.

(alvanias)

At least two species of small gastropods usually associated with siltclay bottom sediments, found on the continental shelf and slope in

Southern New England and on the slope further south

Arthropoda Ampelisca spp. Six species of tube-dwelling amphipods found inshore and on the shelf,

very abundant in some localities

Phoxocephalus holbolli Amphipod that characteristically inhabits fine sand sediments on the

continental shelf

Trichophoxus epistomus Widely distributed burrowing amphipod that inhabits sand and silty

sand sediments on the shelf

Cancer spp.

(rock crabs)

Two species that inhabit a variety of bottom sediments throughout the

Mid-Atlantic shelf

Echinodermata Echinocardium cordatum

(sea potato)

Burrowing heart urchin that usually inhabits sand sediments in

moderately shallow water, found only in the southern part of the region

Astropecten spp. Two species of burrowing sea stars that are common in silty sand

bottom sediments on the northern half of the Mid-Atlantic shelf

Amphilimna olivacea Brittle star that inhabits moderately deep water in Southern New

England along the outer continental shelf and upper slope
Page 25

Figure 2.1. Northeast U.S. Shelf Ecosystem, showing the boundaries of the continental shelf (50-fathom line), the EEZ (200-mi limit),

and the three principal systems (Gulf of Maine, Georges Bank, and Mid-Atlantic Bight).

Canada

34°

34°

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Georges

 Bank

Gulf of

 Maine

Mid-Atlantic

 Bight

#

Cape Cod

#

Long Island

#

Delaware Bay

#

Chesapeake Bay

#

Cape Hatteras

50 fathoms

Outer Limit

 of EEZ
Page 26

Figure 2.2. Gulf of Maine, showing the 50-fathom and 100-fathom lines of the continental shelf, the boundary between the U.S.

Canadian EEZs, and the principal physiographic features.

Georges

 Bank

Canada

U.S.

Jordan

 Basin

Wilkinson

 Basin

Great South

 Channel

Nantucket

 Shoals

Northeast 

 Channel

#

Jeffreys

 Ledge

#

Cape

 Cod

#

Casco Bay

#

Penobscot

 Bay

100 f

50 f

41° 42° 43° 44°

71°

71°

70°

70°

69°

69°

68°

68°

67°

67°
Page 27

Figure 2.3. Northeast Region sediments. (Modified from Poppe, Schlee, Butman, et al. (1989), and Poppe, Schlee, and Knebel (1989).)
Page 28

Figure 2.4. Water mass circulation patterns in the Georges Bank - Gulf of Maine region. (Depth in meters. Source: Valentine and Lough

(1991).)
Page 29

Figure 2.5. Distribution of the seven major benthic assemblages in the Gulf of Maine. (1 = sandy offshore banks; 2 = rocky offshore

ledges; 3 = shallow (<50 m) temperate bottoms with mixed substrate; 4 = boreal muddy bottom, overlain by Maine

Intermediate Water, 50-160 m (approximate); 5 = cold deep water, species with broad tolerances, muddy bottom; 6 = deep

basin warm water, muddy bottom; and 7 = upper slope water, mixed sediment. Source: Watling (1998).)
Page 30

Figure 2.6. Sedimentary provinces of eastern Georges Bank. (Numbered 1-7. Based on criteria of seafloor morphology, texture,

sediment movement and bedforms, and mean tidal bottom current speed (shown as hatched-line contours ranging between

10 and 40 cm/s). Relict moraines (bouldery seafloor) are enclosed by dashed lines. See Table 2.4 for descriptions of

provinces. Source: Valentine and Lough (1991).)
Page 31

Figure 2.7. Mid-Atlantic Bight submarine morphology. (Source: Stumpf and Biggs (1988).)

Figure 2.8. Major features of the Mid-Atlantic and Southern New England continental shelf. (Source: Stumpf and Biggs (1988).)
Page 32

Figure 2.9. Summary of all reef habitats (except biogenic, such as mussel or oyster beds) in the Mid-Atlantic Bight. (Source: Steimle and

Zetlin (2000).)
Page 33

Figure 2.10. Schematic representation of major macrofaunal zones on the Mid-Atlantic shelf. (Approximate location of ridge fields

indicated. Source: Reid and Steimle (1988).)
Page 34

Figure 2.11. Bathymetry of the U.S. Atlantic continental margin. (Contour interval is 200 m below 1000 m of water depth, and 100 m

above 1000 m of water depth. Axes of principal canyons and channels are shown by solid lines (dashed where uncertain or

approximate). Source: Tucholke (1987).)
Page 35

Figure 2.12. Geographic distribution of the density (top) and biomass (bottom) of all taxonomic groups of benthic invertebrates in the

New England region, 1956-1965. (Source: Theroux and Wigley (1998).)
Page 36

Figure 2.13. Percentage composition (by number of individuals) and density (as mean number of individuals per square meter of bottom

area) of the major taxonomic groups of New England benthic invertebrate fauna in relation to water depth. (Source: Theroux

and Wigley (1998).)
Page 37

Figure 2.14. Percentage composition (by wet weight) and biomass (as mean wet weight in grams of individuals per square meter of bottom

area) of the major taxonomic groups of New England benthic invertebrate fauna in relation to water depth. (Source: Theroux

and Wigley (1998).)
Page 38

Figure 2.15. Percentage composition (by number of individuals and by wet weight) and density and biomass (as mean number and wet

weight (in grams), respectively, of individuals per square meter of bottom area) of the major taxonomic groups of New

England benthic invertebrate fauna in relation to bottom type. (Source: Theroux and Wigley (1998).)
Page 39

Figure 2.16. Geographic distribution of the density (as mean number of individuals per square meter) of all taxonomic groups of benthic

invertebrates in the Mid-Atlantic region, 1956-1965. (Source: Wigley and Theroux (1981).)
Page 40

Figure 2.17. Geographic distribution of the biomass (as mean wet weight in grams per square meter) of all taxonomic groups of benthic

invertebrates in the Mid-Atlantic region, 1956-1965. (Source: Wigley and Theroux (1981).)
Page 41

Figure 2.18. Percentage composition (by number of individuals and by wet weight) and density and biomass (as mean number and wet

weight (in grams), respectively, of individuals per square meter of bottom area) of the major taxonomic groups of MidAtlantic benthic invertebrate fauna in relation to water depth. (Source: Wigley and Theroux (1981).)
Page 42

Figure 2.19. Percentage composition (by number of individuals and by wet weight) and density and biomass (as mean number and wet

weight (in grams), respectively, of individuals per square meter of bottom area) of the major taxonomic groups of MidAtlantic benthic invertebrate fauna in relation to bottom type. (Source: Wigley and Theroux (1981).)
Page 43

3. FISHING GEAR AND PRACTICES USED IN THE NORTHEAST REGION

The geographical area of responsibility of the

Northeast Region also falls variously within the jurisdiction of the New England Fishery Management Council

(NEFMC) and Mid-Atlantic Fishery Management Council

(MAFMC), as well as the individual states from Maine to

North Carolina which are represented by the Atlantic

States Marine Fisheries Commission (ASMFC). These

organizations are responsible for the management of many

different fisheries, extending from the upper reaches of

rivers and estuaries to the outer limit of the Exclusive

Economic Zone, located 200 mi offshore, well beyond the

edge of the continental shelf (Figure 2.1). In addition, some

federally managed species that are found at certain times of

year in the Northeast Region are managed by the South

Atlantic Fisheries Management Council.

Fishing gear types used to land 1% or more of any

species managed by either the NEFMC or MAFMC are

listed in Table 3.1, and gear types that contributed 1% or

more of any individual state’s total landings for federally

and state-managed species are listed in Table 3.2.

Although certain gear types used in state waters are not

managed by the federal government, they may adversely

impact EFH that is designated in nearshore, estuarine, and

riverine areas. Consequently, Table 3.3 lists all fishing gear

types and harvesting techniques that are identified in

Tables 3.1 and 3.2, and indicates whether they are used in

estuaries, coastal waters (0-3 mi), or offshore waters (3-200

mi). Since the seafloor is the location of the habitat types

most susceptible to gear disturbances, Table 3.3 also

indicates which gear types and harvesting techniques

contact the bottom, and which ones are regulated under a

federal fishery management plan (FMP). This document

considers a gear to be regulated under a federal FMP if it is

typically utilized to harvest fish under a federal vessel or

operators permit. Most of the gear types listed in Table 3.3

are described in this chapter of the document.

Unless otherwise noted by reference in the following

descriptions, the information used to describe gear types

and fishing practices in the Northeast Region was obtained

from four primary sources: Sainsbury (1996), DeAlteris

(1998), Everhart and Youngs (1981), and the report of a

panel of science and fishing industry representatives on

the effects of fishing gear on marine habitats in the region

(NREFHSC 2002). Information regarding the use of fishing

gears in state waters within the region was extracted from

Stephan et al. (2000). The gear descriptions in this

document are based on information that was available to

the authors and, in some cases, are incomplete.

BOTTOM-TENDING MOBILE GEAR

Bottom Trawls

Trawls are classified by their function, bag construction, or method of maintaining the mouth opening.

Function, in turn, may be defined by the part of the water

column where the trawl operates (e.g., bottom) or by the

species that it targets (Hayes 1983). Bottom trawls are

designed to be towed along the seafloor and to catch a

variety of demersal fish and invertebrate species. Midwater trawls are designed to catch pelagic species in the

water column, and do not normally contact the bottom.

They are described under “Pelagic Gear” later in this chapter.

Three general types of bottom trawl, are used in the Northeast

Region, but one of them, the bottom otter trawl, accounts for

nearly all commercial bottom trawling activity.

Otter Trawls

There is a wide range of otter trawl types used in the

Northeast Region because of the diversity of fisheries

prosecuted and bottom types encountered in the region.

The specific gear design is often a result of the target

species (e.g., whether they are found on or off the bottom)

as well as the composition of the bottom (i.e., smooth

versus rough and soft versus hard). Bottom otter trawls are

used to catch a variety of species throughout the region

and account for a higher proportion of the catch of

federally managed species than any other gear type in the

region (Tables 3.1 and 3.2).

There are three components of the otter trawl that

come in contact with the seafloor: the doors, the ground

cables and bridles which attach the doors to the wings of

the net, and the sweep which runs along the bottom of the

net mouth. The footrope of the net is attached to the

sweep. Bottom trawls are towed at a variety of speeds, but

average about 5.6 km/hr (3 knots).

Use of this gear in the region is managed under several

federal FMPs. Bottom trawling is also subject to a variety

of state regulations throughout the region.

Doors

The traditional otter board or door is a flat, rectangular

wood structure with steel fittings and a steel “shoe” along
Page 44

the leading and bottom edges that prevents damage and

wear of the door as it drags over the bottom. Wooden trawl

doors are still in use in the Northeast Region, but they have

been largely replaced by heavier, more efficient, steel

doors. Two types of steel doors commonly used in the

region are the V-shaped “Thyboron” door and the

cambered (or curved) “Bison” door (pers. comm.; Alan

Blott, National Marine Fisheries Service, North Kingstown,

RI). Either type of door can be slotted to allow some water

to flow through the door, further increasing its efficiency.

Steel “shoes” can be added at the bottom of the door to aid

in keeping it upright and take the wear from bottom contact.

The sizes and weights of trawl doors used in the Northeast

Region vary according to the size and type of trawl, and the

size and horsepower of the vessel. Large steel doors (4-5

m2

) weigh between 700 kg and 1 mt.

It is the location on each door at which the towing

cable, or “warp,” is attached that creates the towing angle,

which in turn creates the hydrodynamic forces needed to

push the door outward and downward, thus spreading the

wings of the net. The nontraditional designs increase the

spreading force of the door by increasing direct pressure

on the face of the door and/or by creating more suction on

the back of the door. On fine-grained sediments, the doors

also function to create a silt cloud that aids in herding fish

into the mouth of the net. On rocky or more irregular

bottom, trawl doors impact rocks in a jarring manner and

can jump distances of 1-2 m (Carr and Milliken 1998).

Ground Cables and Bridles

Steel cables are used to attach the doors to the wings

of the net. A ground cable runs along the bottom from each

door to two other cables (i.e., the upper and lower

“bridles”) that diverge to attach to the top and bottom of

the net wing. The lower bridle also contacts the bottom. In

New England, fixed rubber disks (“cookies”) or rollers are

attached to the ground cables and lower bridles to assist

the passage of the trawl over the bottom. For bottom

trawling, in very general terms, bridles vary in length from 9

to 73 m (30 to 240 ft), while ground cables vary from 0 to 73

m (0 to 240 ft), depending upon bottom conditions, towing

speed, and fish behavior.

Sweeps

Two types of sweep are used on smooth bottom in

New England (Mirarchi 1998). In the traditional chain

sweep, loops of chain are suspended from a steel cable,

with only 2-3 links of the chain touching bottom. Contact

of the chain with the bottom reduces the buoyancy of the

trawl so that it skims just a few inches above the bottom to

catch species such as squid and scup that swim slightly

above the bottom. The other type of New England smoothbottom sweep is used to catch flounder. Instead of a cable,

it uses a heavy chain with rubber cookies stamped from

automobile tires. This latter type of sweep is always in

contact with the bottom. The cookies vary in diameter from

10 to 41 cm (4 to 16 in) and do not rotate (Carr and Milliken

1998).

On rough bottoms, roller and rockhopper sweeps are

used (Carr and Milliken 1998). In the roller sweeps, vertical

rubber rollers as large as 91 cm (36 in) in diameter are placed

at intervals along the sweep. In fact, however, only the

“rollers” that are located at or near the center of the sweep

actually “roll” over the bottom; because the sweep is

shaped in a curve, the others are oriented at increasing

angles to the direction of the tow and do not rotate freely as

they are dragged over the bottom (pers. comm.; Alan Blott,

National Marine Fisheries Service, North Kingstown, RI).

In New England, roller sweeps have been largely replaced

with “rockhopper” sweeps that use larger fixed rollers, and

are designed to “hop” over rocks as large as 1 m in

diameter. Small rubber “spacer” disks are placed between

the larger rubber disks in both types of sweep. Rockhopper

gear is no longer used exclusively on hard-bottom habitats,

but is actually quite versatile and is used in a variety of

habitat types (Carr and Milliken 1998). The range of

footrope/headrope lengths for bottom trawls used in the

New England inshore day-boat fleet is 18/12 m (60/40 ft) for

smaller (12-m or 40-ft) vessels, and increases up to 42/36 m

(140/120 ft) for larger vessels (21 m/70 ft or larger) (pers.

comm.; Alan Blott, National Marine Fisheries Service,

North Kingstown, RI).

Factors Affecting Area Swept by Bottom Otter

Trawls

The area of bottom that is contacted by a bottom otter

trawl during a tow is a function of the linear distance

covered (a product of the speed of the net over the bottom

and the duration of the tow) and the width of the tow path.

The width of the tow path is the distance between the

doors (i.e., across the mouth of the net) and varies

according to the force exerted on the doors, the ground

cables, the sweep, and the net as it is towed over the

bottom. Nets towed at higher speeds, or that offer more

resistance to being towed through the water and over the

bottom, are swept back in a more pronounced parabolic

shape than nets towed at slower speeds, or nets that offer

less resistance. Mirarchi (1998) has estimated that on

smooth bottom and at a towing speed of 5.6 km/hr (3 knots),

the linear distance between the doors is equal to roughly

one-third of the total length of the ground cables, the

bridles, and the sweep. Thus, a bottom trawl with a 30-m

(100-ft) sweep and 75-m (250-ft) bridles and ground cables on

either side of the net would sweep an area 60 m (200 ft) wide.
Page 45

Some Specific Types of Otter Trawl Used in

 the Region

A number of different types of bottom otter trawl used

in the Northeast Region are specifically designed to catch

certain species of fish, on specific bottom types, and at

particular times of year. Some of the major differences in

bottom trawl design are described here, but these

descriptions are not very specific because there are many

variations of each basic trawl type, and because detailed

information on all the different types of bottom trawl used

in the region are lacking. Furthermore, the performance of

any bottom trawl (i.e., how it “behaves” as it is towed over

the bottom), and the degree to which it contacts and

disturbs the bottom during any tow, are affected by a

number of factors such as how much trawl wire is set out

(relative to the depth), the bottom type and topography,

the amount of bottom current, etc.

Flatfish trawls, described by Mirarchi (1998), are

designed with a low net opening between the headrope and

the footrope and more ground rigging (i.e, rubber cookies

and chain) on the sweep. This type of trawl is designed so

that the sweep will follow the contours in the bottom, and

to get fish like flounders -- that lie in contact with the

seafloor -- up off the bottom and into the net. It is used on

smooth mud and sand bottoms. A high-rise or fly net with

larger mesh has a wide net opening and is used to catch

demersal fish that rise higher off the bottom than flatfish

(NREFHSC 2002).

Bottom otter trawls used to catch species like scup and

squid that swim over the bottom are rigged very lightly,

with loops of chain suspended from the sweep (Mirarchi

1998). This gear is designed to skim along the seafloor with

only two or three links of each loop of chain touching the

bottom (details are described above). This type of trawl is

also used on smooth bottoms.

Bottom otter trawls that are used on “hard” bottom

(i.e., gravel or rocky bottom), or mud or sand bottom with

occasional boulders, are rigged with rockhopper gear. The

purpose of the “ground gear” in this case is to get the

sweep over irregularities in the bottom without damaging

the net. The purpose of the sweep in trawls rigged for

fishing on smooth bottoms is to herd fish into the path of

the net (Mirarchi 1998).

Small-mesh trawls are used in the Northeast Region to

capture northern and southern shrimp, silver hake

(whiting), butterfish, and squid. Bottom trawls used to

catch northern shrimp in the GOM are smaller than most

fish trawls. Footropes range in length from 12 m to over 30

m (40-100 ft), but most are 15-27 m (50-90 ft). Regulations

require that northern shrimp trawls may not be used with

ground cables, and that the “legs” of the bridles not exceed

27 m (90 ft). These regulations were implemented in order to

reduce the amount of area swept during a tow, thus

reducing the bycatch of groundfish species. Northern

shrimp trawls are also required to have Nordmore grates in

the funnel of the net which reduce the retention of

groundfish that enter the net. There has been a trend in

recent years towards the use of heavier, larger roller and/or

rockhopper gear in this fishery (ASMFC 2004).

The raised-footrope trawl was designed especially for

fishing for silver hake, red hake, and dogfish. It was

designed to provide vessels with a means of continuing to

fish for small mesh species without catching groundfish.

Raised-footrope trawls can be rigged with or without a

chain sweep. If no sweep is used, drop chains must be

hung at defined intervals along the footrope. In trawls with

a sweep, chains connect the sweep to the footrope. Both

configurations are designed to make the trawl fish about

0.45-0.6 m (1.5-2 ft) above the bottom (Carr and Milliken

1998). Although the doors of the trawl still ride on the bottom,

underwater video and observations in flume tanks have

confirmed that the sweep in the raised-footrope trawl has

much less contact with the seafloor than does the traditional

cookie sweep that it replaces (Carr and Milliken 1998).

An important consideration in understanding the

relative effects of different otter trawl configurations is

their weight in water relative to their weight in air.

Rockhopper gear is not the heaviest type of ground gear

used in this region since it loses 80% of its weight in water

(i.e., a rockhopper sweep that weighs 1000 lb on land may

only weigh 200 lb in water). Plastic-based gear has the

smallest weight-in-water to weight-in-air ratio (approximately 5%). For the same reasons, steel doors are much

heavier in water than wooden doors.

Pair Trawls

Bottom pair trawls are towed over the bottom by two

vessels, each towing one warp of the net. The mouth of the

net is kept open by the outward pull provided by the two

boats, so that no otter boards are required. By utilizing the

combined towing power of the two vessels, and as no otter

boards are needed, a larger net may be worked than would

be possible by a single vessel. Alternatively, two vessels

of low horsepower can combine to use this method

efficiently. Bottom pair trawls are effective at catching

demersal species such as cod and flatfish as well as small

pelagic species.

This gear is rigged more simply than an otter trawl,

with the warps being connected directly to the bridles from

each wing of the net. Normally, a greater warp length/water

depth ratio than for otter trawling is required because there

are no doors to increase the drag of the gear in the water.

The additional “scope” allows the warps to tend the

bottom for some distance ahead of the bridles, creating a

mud cloud that herds fish into the opening of the net. In

some operations, ground cables may be rigged ahead of the

bridles with weights placed at the connection to the warps.

Pair trawling for groundfish species managed by the

NEFMC is currently prohibited.
Page 46

Danish and Scottish Seines

Danish or long seining, or “anchor dragging,” was

developed in the 1850s prior to the advent of otter trawling.

The Danish seine is a bag net with long wings that includes

long warps set out on the seafloor enclosing a defined area.

As the warps are retrieved, the enclosed triangular area

reduces in size. The warps dragging along the bottom herd

the fish into a smaller area, and eventually into the net

mouth. The gear is deployed by setting out one warp, then

the net, and finally the other warp. On retrieval of the gear,

the vessel is anchored. This technique of fishing is aimed

at specific schools of fish located on smooth bottom.

In contrast to Danish seining, if the vessel tows ahead

while retrieving the gear, then this is referred to as Scottish

seining or “fly-dragging.” This method of fishing is

considered more appropriate for working small areas of

smooth bottom, surrounded by rough bottom.

Scottish and Danish seines have been used

experimentally in U.S. demersal fisheries. Space conflicts

with other mobile and fixed gears have precluded the

further development of this gear in the United States, as

compared to northern Europe.

This activity is managed under federal FMPs.

Hydraulic Clam Dredges

Atlantic Surfclam and Ocean Quahog Fishery

Hydraulic clam dredges have been used in the Atlantic

surfclam fishery for over five decades, and in the ocean

quahog fishery since its inception in the early 1970s. The

typical dredge is 3.7 m (12 ft) wide and about 6.7 m (22 ft)

long, and uses pressurized water jets to wash clams out of

the seafloor. Towing speed at the start of the tow is about

4.6 km/hr (2.5 knots), and declines as the dredge

accumulates clams. The dredge is retrieved once the vessel

speed drops below about 2.8 km/hr (1.5 knots), which can

be only a few minutes in very dense beds. However, a

typical tow lasts about 15 min. The water jets penetrate the

sediment in front of the dredge to a depth of about 20-25 cm

(8-10 in) and help to “drive” the dredge forward.The water

pressure that is required to fluidize the sediment varies from

50 lb/in2

 (psi) in coarse sand to 110 psi in finer sediments.

The objective is to use as little pressure as possible since

too much pressure will blow sediment into the clams and

reduce product quality. The “knife” (or “cutting bar”) on

the leading bottom edge of the dredge opening is 14 cm (5.5

in) deep for surfclams and 9 cm (3.5 in) for ocean quahogs.

The knife “picks up” clams that have been separated from

the sediment and guides them into the body of the dredge

(“the cage”).

Hydraulic clam dredges can be operated in areas of

large-grain sand, fine sand, sand with small-grain gravel,

sand with small amounts of mud, and sand with very small

amounts of clay. Most tows are made in large-grain sand.

Surfclam/quahog dredges are not fished in clay, mud,

pebbles, rocks, coral, large gravel >0.5 in, or seagrass beds.

Use of this gear in the region is managed under federal

FMPs, and is also regulated in state waters in the MidAtlantic region, especially in shallow waters where

submerged aquatic vegetation grows.

Softshell Clam Fishery

Hydraulic dredges are also used in the softshell (Mya

arenaria) fishery in state waters of Maryland and Virginia.

In this fishery, the dredge manifold and blade are located

just forward of an escalator, or conveyor belt, that carries

the clams to the deck of the vessel. Escalator dredges are

typically operated from 15-m (49-ft) vessels in water depths

of 2-6 m (7-20 ft). This gear cannot be operated in water

depths less than one-half the length of the escalator.

Use of the escalator dredge is not managed under

federal FMPs. This gear is subject to many of the same

state laws and regulations that apply to surfclam and ocean

quahog dredges in state waters.

Sea Scallop Dredges

The New Bedford-style scallop dredge is the primary

gear used in the Georges Bank and Mid-Atlantic sea

scallop fishery, and is very different than dredges utilized

in Europe and the Pacific because it has no teeth on its

leading edge.

The forward edge of the New Bedford-style dredge

includes a cutting bar which rides above the surface of the

substrate, creating turbulence that stirs up the substrate

and kicks objects (including sea scallops) up from the

surface of the substrate into the bag. Shoes on the cutting

bar ride along the substrate surface. A sweep chain is

attached to each shoe and to the bottom of the ring bag

(Smolowitz 1998). The bag, which is made of metal rings

with chafing gear on the bottom and of twine mesh on the

top, drags on the substrate when fished. Tickler chains run

from side to side between the frame and the ring bag, and, in

hard-bottom scalloping, a series of rock chains run from

front to back to prevent large rocks from getting into the

bag. New Bedford-style dredges are typically 4.3 m (14 ft)

wide; one or two of them are towed by single vessels at

speeds of 4-5 knots (7.4-9.3 km/hr). New Bedford-style

dredges used along the Maine coast are smaller. Dredges

used on hard bottoms are heavier and stronger than

dredges used on sand. Towing times are highly variable,

depending on the density of marketable-sized sea scallops

at any given location. Tows can be as short as 10 min or as

long as 1 hr (pers. comm.; Ron Smolowitz, industry advisor

to NEFMC Habitat Committee, Falmouth, MA).

In the Northeast Region, scallop dredges are used in

high- and low-energy sand environments, and high-energy

gravel environments. Although gravel exists in low-energy
Page 47

environments of deepwater banks and ridges in the GOM,

the fishery is not prosecuted there.

The leading edge of scallop dredges used in Europe,

Australia, and New Zealand to catch other species of

scallop that “dig” into the bottom have teeth that dig into

the substrate. A very limited amount of scallop dredging

with toothed dredges takes place along the U.S. and

Canadian coast of the GOM. These toothed dredges are

used by smaller vessels that are not able to tow a New

Bedford-style dredge fast enough (4-5 knots) to effectively

catch scallops.

The use of scallop dredges in federal waters of the

Northeast Region is managed under federal FMPs.

Other Nonhydraulic Dredges

Quahog Dredges

Mahogany quahogs (a colloquial name for ocean

quahogs in New England) are harvested in eastern Maine

coastal waters using a dredge that is essentially a large

metal cage on skis, with 15-cm (6-in) long teeth projecting at

an angle off the leading bottom edge (pers. comm.; Pete

Thayer, Maine Department of Marine Resources, West

Boothbay Harbor, ME). The teeth rake the bottom and lift

the quahogs into the cage.

This fishery takes place in small areas of sand and

sandy mud found among bedrock outcroppings in depths

of 9-76 m (30-250 ft) in state and federal coastal waters north

of 43°20' N latitude. These dredges are used on small boats

(approximately 9-12 m (30-40 ft) long). Because water

pressure is not used to dislodge the clams from the

seafloor, all the power required to pull these dredges

forward is provided by the boat’s engine.

This dredging activity is managed under a federal

FMP. Maine state regulations limit the length of the cutter

bar to 91 cm (36 in).

Oyster, Crab, Mussel, and Whelk Dredges

The oyster dredge is a toothed dredge consisting of a

steel frame 0.5-2.0 m (2-7 ft) wide, a tow chain or wire

attached to the frame, and a bag to collect the catch. The

teeth are 5-10 cm (2-4 in) in length. The bag is constructed

of rings and chain links on the bottom to reduce the

abrasive effects of the seafloor, and of twine or webbing on

top. In the Northeast Region, oyster dredges are used in

state waters from Connecticut to North Carolina to harvest

the eastern oyster (Crassostrea virginica).

Blue crabs (Callinectes sapidus) are harvested with

dredges (or “scrapes”) similar to oyster dredges in state

waters in New York, New Jersey, Delaware, Virginia, and

North Carolina. Stern-rig dredge boats (approximately 15 m

(49 ft) long) tow two dredges in tandem from a single chain

warp. The dredges are equipped with 10-cm (4-in) long

teeth that rake the crabs out of the bottom.

Dredges are also used to harvest blue mussels

(Mytilus edulis) in state waters of Maine and Massachusetts, and to harvest channeled and knobbed whelks

(Busycon canaliculatus and B. carica, respectively) in

New York, Delaware, and Virginia.

These dredging activities are not managed under

federal FMPs. The design and use of crab and shellfish

dredges are subject to various restrictions in state waters.

Bay Scallop Dredges

The bay scallop (Argopecten irradians) dredge may

be 1.0-1.5 m (3.3-4.9 ft) wide and about twice as long. The

simplest bay scallop dredge can be just a mesh bag

attached to a metal frame that is pulled along the bottom.

For bay scallops that are located on sand and pebble

bottom, a small set of raking teeth is set on a steel frame,

and skids are used to align the teeth and the bag. Bay

scallop dredges are used in state waters of Massachusetts,

Rhode Island, New York, and North Carolina.

This dredging activity is not managed under federal

FMPs.

Sea Urchin Dredges

Similar to a simple bay scallop dredge, the sea urchin

dredge is designed to avoid damaging the catch. It has an

upturned, sled-like shape at the front that includes several

automobile leaf springs tied together with a steel bar. A

tow bail is welded to one of the springs and a chain mat is

rigged behind the mouth box frame. The frame is fitted with

skids or wheels. The springs act as runners, enabling the

sled to move over rocks without hanging up. The chain mat

scrapes up the urchins. The bag is fitted with a cod-end for

ease of emptying. This gear is generally used in depths up

to 27.5 m (90 ft). Sea urchin dredges are used in state

waters in the GOM to harvest green sea urchins

(Strongylocentrotus drobachiensis).

This dredging activity is not managed under federal

FMPs.

Seines

Beach Haul Seines

The beach seine resembles a wall of netting of

sufficient depth to fish from the sea surface to the seafloor,

with mesh small enough that the fish do not become

“gilled.” A floatline runs along the top to provide

floatation, and a leadline with a large number of attached

weights runs along the bottom to ensure that the net
Page 48

maintains good contact with the bottom. Tow lines are

fitted to both ends.

The use of a beach seine generally starts with the net

on the beach. One end is pulled away from the beach,

usually with a small skiff or dory, and is taken out and

around and finally back to shore. Each end of the net is

then pulled in towards the beach, concentrating the fish in

the middle of the net. The middle of the net is eventually

brought onshore as well, and the fish are removed. This

gear is generally used in relatively shallow inshore areas.

This activity is not managed under federal FMPs.

Long Haul Seines

The long haul seine is set and hauled in shallow

estuarine and coastal areas by one or two boats. The net is

a single wall of small-mesh netting (i.e., <5 cm (2 in) as

stretched mesh) that is usually >400 m (1310 ft) long and

about 3 m (10 ft) deep. In a single-boat operation, one end

of the net is attached to a pole driven into the bottom, and

the net is set in a circle. After closing the circle, the net is

hauled into the boat, reducing the size of the circle, and

concentrating the fish. Finally, the live fish are brailed or

dipnetted out of the net. In two-boat operations, the net is

set as the boats travel in opposite directions, in a circle,

from the same starting point. When the net is all out, the

boats turn on the same course and pull the seine for some

distance before they come together to close the net.

This activity is not managed under federal FMPs.

Stop Seines

The stop-seine fishery evolved from the traditional

weir fishery for Atlantic herring in Maine (see “Trap Nets”

later in this chapter) and involves the setting of nets across

a cove with a narrow entrance after the herring enter, thus

blocking their escape. Once the fish are “shut off,” the

fishermen wait until the fish enter a small “pocket” in the

net. Once they enter the pocket, they are removed with a

small purse seine and transferred to boats called “carriers”

which bring the catch ashore (NOAA/NMFS 2005). This

gear is not used much any more (ASMFC 1999a).

This activity is not managed under federal FMPs.

BOTTOM-TENDING STATIC GEAR

Pots

Pots are small, portable, rigid traps that fish and

invertebrates enter through small openings, with or

without enticement by bait, but can only leave with

difficulty. They are used to capture lobsters, crabs, black

sea bass, eels, and other bottom-dwelling species seeking

food or shelter. Pot fishing can be divided into two general

classifications: 1) inshore potting in estuaries, lagoons,

inlets, and bays in depths up to about 75 m (250 ft); and 2)

offshore potting using larger and heavier vessels and gear

in depths up to 730 m (2400 ft) or more.

Lobster Pots

Originally, pots used to harvest American lobster

(Homarus americanus) were constructed of wooden laths

with single, and later, double, funnel entrances made from

net twine. Today, almost all of the pots are made from

coated wire mesh. They are rectangular and are divided

into two sections, the “kitchen” and the “parlor.” The

kitchen has an entrance on both sides of the pot and is

baited. Lobsters enter either chamber then move to the

parlor through a long, sloping tunnel to the parlor. Escape

vents are installed in both areas of the pot to minimize the

retention of sublegal-sized lobsters. Rock crabs (Cancer

spp.) are also harvested in lobster pots.

Lobster pots are fished as either a single pot per buoy,

two or three pots per buoy, or strung together in “trawls” of

up to 100 pots. Single pots are often used in rough, hardbottom areas where lines connecting pots in a trawl line

tend to foul on bottom structure. They are fished in trawls

on flatter types of bottom. The area of bottom that comes in

contact with a single trap during the setting and hauling

process is small, but the cumulative effect of several million

pots being set and hauled several times a week may be

significant (Smolowitz 1998). The total number of traps

used in the lobster fishery increased from just over one

million in 1970 to over four million in 1998 (ASMFC 2000).

According to NREFHSC (2002), important features of

lobster pots and their use are the following:

• About 95% of lobster pots are made of plasticcoated wire.

• Pots in trawls are connected by “mainlines”

which either float off the bottom, or, in areas

where they are likely to become entangled with

marine mammals, sink to the bottom.

• Soak time depends on season and location —

usually 1-3 days in inshore waters in warm

weather, but up to several weeks in colder

waters.

• Offshore pots are larger (>1.2 m (4 ft) long) and

heavier [~45 kg (100 lb)] than inshore pots, with

an average of about 40 pots per trawl. They are

usually deployed for 1 wk at a time.

Although the offshore component of the fishery is

regulated under federal rules, American lobster is not

managed under a federal FMP.
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Fish Pots

Fish pots used to catch black sea bass, ocean pout,

and scup (Table 3.1) are similar in design to lobster pots,

and are usually fished singly or in trawls of up to 25 pots

and in shallower waters than offshore lobster pots or red

deepsea crab pots. Pots may be set and retrieved 3-4 times

per day when fishing for scup.

Atlantic hagfish (Myxine glutinosa) pots are 55-gal

plastic barrels with 3-6 entrance funnels and several rows

of approximately 1-cm (3/8-in) escape holes. They are set

45-63 m (150-210 ft) apart to depths of 90-282 m (300-930 ft).

Small boats fish 20-40 traps in a string, hauling several

times per trip, and larger vessels fish 80-200 traps in a

string, hauling 1-2 times per day. Soak time varies from 6 to

24 hr. The captain of a 26-m (85-ft) hagfish boat reported

that he sets and hauls 1,000 traps (five sets of 200 traps) on

each 5-day trip (NEFSC 2004).

Cylindrical pots are typically used for capturing

American eels (Anguilla rostrata) in rivers and estuaries;

however, half-round and rectangular pots are also used.

They are hauled and set in a manner similar to that of

lobster pots.

The use of fish pots in the black sea bass, scup, and

ocean pout fisheries is managed under federal FMPs.

Atlantic hagfish and American eel fishing activities in the

region are not managed under federal FMPs.

Crab Pots

Crab pots are used in inshore coastal and estuarine

waters in the Mid-Atlantic states to catch blue crabs

(Callinectes sapidus). These pots typically consist of wire

mesh. A horizontal wire partition divides the pot into an

upper and lower chamber. The lower chamber is entered

from all four sides through small wire tunnels. The partition

bulges upward in a fold about 20 cm (8 in) high for about

one-third of its width. In the top of the fold are two small

openings that give access to the upper chamber. These

crab pots are always fished as singles, and are hauled by

hand in small boats, or by a pot hauler in larger boats. They

are generally fished after an overnight soak, except early

and late in the season. These pots are also effective for

American eels. This activity is not managed under a federal

FMP.

For red deepsea crabs (Chaceon quinquedens), the

traditional-style pots are wood and wire traps that are 1.2 m

long, 0.75 m wide, and 0.5 m high (48 x 30 x 20 in) with a top

entry. A second style of pot used in this fishery is conical

in shape, 1.3 m (4 ft) in diameter, and 0.45 m (22 in) high with

a top-entry funnel. According to information provided in

the 2002 red crab FMP (NEFMC 2002), vessels use an

average of 560 pots that are deployed in trawls of 75-180

pots per trawl along the continental slope at depths of 400-

800 m (1300-2600 ft). The pots are transported to and from

the fishing grounds during each trip and are generally

hauled daily. The vessels are large, typically measuring 27-

46 m (90-150 ft) long. There are six vessels engaged in this

fishery, which is managed by the NEFMC.

Whelk Pots

Wood and wire pots are used in southern Massachusetts waters to catch whelks, primarily the channeled whelk

(pers. comm.; Frank Germano, Massachusetts Division of

Marine Fisheries, New Bedford, MA). The pots are fished

singly or in trawls with as many as 40 pots to a trawl in

depths of 1.5-27 m (5-90 ft). They are set mostly on sandy

bottom, often in or near seagrass beds. They are open at

the top and baited, mostly with horseshoe crabs. Whelk

pots are also used in coastal waters off New Jersey,

Delaware, Maryland, and Virginia.

This activity is not managed under federal FMPs.

Trap Nets

A trap net is generally a largescale device that uses the

seabed and sea surface as boundaries for the vertical

dimension. The gear is installed at a fixed location for a

season, and is passive, as the animals voluntarily enter the

gear. Trap nets are used in nearshore areas through which

fish regularly move or congregate. They are of varying size

and configuration and rely for their effectiveness on

preventing fish from leaving the trap once they have

entered it. They are made of a leader or fence that directs

fish into the trap, and a heart, or parlor, that leads fish via a

funnel into the bay or trap section where the fish are held

until they are harvested by the fishermen. Four specific

types of trap net are described in this document.

Fish Pound Nets

Pound nets are constructed of netting that is attached

to piles or stakes driven into the seafloor. Pound nets have

three sections: the leader, the heart, and the pound. The

leader (there may be more than one) may be as long as 400

m (1300 ft), and is used to direct fish into the heart(s) of the

net. One or more hearts are used to further funnel fish into

the pound and prevent escapement. The pound, which

may be as large as a 15-m (49-ft) square, holds the fish until

the net is emptied. The pocket usually has a netting floor;

the fish are concentrated for “brailing” (a “brailer” is a very

large dip net) by gradually bringing the sidewalls and

bottom netting into boats working inside the pocket.

These nets are generally fished in waters <50 m (160 ft)

deep. A number of federally managed species are

harvested in pound nets (Table 3.1).

This activity is not managed under a federal FMP.
Page 50

Fyke Nets

Constructed of a series of wood or metal hoops

covered with netting, fyke nets are 2.5-5.0 m (8.2-16.4 ft)

long. There are usually two wings of netting at the

entrance which are attached to upright stakes and give

the overall net a “Y-shape.” (Fyke nets that don’t have

wings are also called hoop nets). There are one or more

funnels inside the net that direct fish to the rear of the

net (the “car”) where they become trapped. Occasionally, a long leader is used to direct fish to the entrance.

Fish are removed by lifting the car out of the water and

loosening a rope securing the rear of the car. These nets

are generally fished in shallow water and used in river

fisheries.

Fyke net fishing activity is not managed under a

federal FMP.

Weirs

A weir is a simple maze that intercepts species that

migrate along the shoreline. Weirs are used in the juvenile

Atlantic herring fishery in eastern Maine and New

Brunswick (Bay of Fundy) where the tides are extreme. At

low tide, closely spaced wooden stakes are driven into the

bottom. In the traditional style of weir, brush is interwoven

between the stakes to form a barrier. Traps formed of

netting have largely replaced the wooden weirs. The fish

encounter the lead that they follow to deeper water, finally

passing into an enclosure or “pound.” Once they are

concentrated in the “pocket,” the fish are removed with a

small purse seine. There are very few weirs currently in use

in Maine (ASMFC 1999a).

This activity is not managed under a federal FMP.

Floating Traps

In New England, much of the shoreline and shallow

subtidal environment is rocky, and stakes cannot be driven

into the bottom. Therefore, a floating trap can be designed

to fish from top to bottom, and be built to suit the individual

location. The webbing of such traps is supported at the sea

surface with floats, and held in place on the seafloor with

large anchors. The net is usually somewhat “T-shaped,”

with the long portion of the net (i.e., the leader) designed to

direct fish into a box of net at the top of the T. The leader is

often made fast to a ring bolt ashore. The catch, design

elements, and scale of these floating traps are similar to

pound nets.

This activity is not managed under a federal FMP.

Bottom Gill Nets

A gill net is a large wall of netting which may be set at

or below the surface, on the seafloor, or at any depth

between. They are equipped with floats at the top and lead

weights along the bottom. Bottom gill nets are anchored or

staked in position. Fish are caught as they try to pass

through the net meshes. Gill nets are highly selective

because the species and sizes of fish caught are highly

dependant on the mesh size of the net. They are used to

catch a wide range of species, including many federally

managed species (Table 3.1).

Sink/Anchor Gill Nets

Gill nets have three components: leadline, netting, and

floatline. Leadlines used in New England are 30 kg (65 lb)

per net; leadlines used in the Mid-Atlantic are slightly

heavier. The netting is monofilament nylon, and the mesh

size varies depending on the target species. Nets are

anchored at each end, using materials such as pieces of

railroad track, sash weights, or Danforth anchors. Anchors

and leadlines have the most contact with the bottom.

Individual gill nets are typically 91 m (300 feet) long and 3.6

m (12 ft) high. Strings of nets may be set out in straight

lines, often across the current, or in various other

configurations (e.g., circles), depending upon bottom and

current conditions. Bottom gillnet fishing occurs in the

Northeast Region in nearshore coastal and estuarine

waters as well as offshore on the continental shelf.

In New England, bottom gill nets are fished in strings

of 5-20 nets attached end to end. They are fished in two

different ways, as “standup” and “tiedown” nets

(Williamson 1998). Standup nets are used to catch

Atlantis,c cod, haddock, pollock, and hake and are soaked

for 12-24 hr. Tiedown nets are set with the floatline tied to

the leadline at 1.8-m (6-ft) intervals, so that the floatline is

close to the bottom, and the net forms a limp bag between

each tie. They are left in the water for 3-4 days, and are used

to catch flounders and goosefish (monkfish). Bottom gill

nets in New England are set in relation to changes in

bottom topography or bottom type where fish are expected

to congregate. Other species caught in bottom gill nets in

New England are spiny dogfish, and skates (Table 3.1).

In the Mid-Atlantic, sink gill nets are fished singly or in

strings of just 3-4 nets (pers. comm.; Glenn Salvador,

National Marine Fisheries Service, Lewes, DE). The MidAtlantic fishery is more of a “strike” type fishery in which

nets are set on schools of fish or around distinct bottom

features and retrieved the same day, sometimes more than

once. They catch species such as bluefish, Atlantic
Page 51

croaker, striped bass, spot, mullet, spiny and smooth

dogfish and skates.

The use of sink gill nets in federal waters is managed

under federal FMPs. The use of gill nets is restricted or

prohibited in some state waters in the region.

Stake Gill Nets

Generally, stake gill nets are used inshore. A small

boat is used to set the net across a tidal flow, and to lift it at

slack tide for removing fish. Wooden or metal stakes run

from the surface of the water into the sediment and are

placed every few meters along the net to hold it in place.

When the net is lifted, the stakes remain in place. Stake gill

nets are used in the Mid-Atlantic states to catch red drum,

bluefish, king mackerel, and Spanish mackerel (Table 3.1).

These activities are not managed under federal FMPs.

Run-Around Gill Nets

The run-around gill net is used in shallow, nearshore

areas to encircle schools of fish. They are set rapidly from

the stern of small, fast boats. The leadline contacts the

bottom, thus preventing the fish from escaping. Runaround gill nets are used in the Northeast Region to catch

red drum (Table 3.1).

Use of this type of gill net is not managed under federal

FMPs.

Bottom Longlines

A longline is a long length of line, often several miles

long, to which short lengths of line (“gangions”) carrying

baited hooks are attached. Longlining for bottom species

on continental shelf areas and offshore banks is

undertaken for a wide range of species. The two primary

federally managed species caught with this gear in 2004 in

the Northeast Region were golden tilefish and redfish

(Table 3.1). Bottom longlines are also referred to as “trot”

lines and are used in the Mid-Atlantic states to harvest

blue crabs.

Bottom longline fishing in the Northeast Region is

conducted with hand-baited gear that is stored in tubs

(“tub trawls”) before the vessel goes fishing, and with

vessels equipped with automated “snap-on” or “racking”

systems. The gangions are 38 cm (15 in) long and 0.9-1.8 m

(3-6 ft) apart. The mainline, hooks, and gangions all contact

the bottom. In the Cape Cod (Massachusetts) longline

fishery, up to six individual longlines are strung together,

for a total length of about 460 m (1500 ft), and are deployed

with 9-11 kg (20-24 lb) anchors. Each set consists of 600-

1200 hooks. In tub trawls, the mainline is parachute cord;

stainless steel wire and monofilament nylon gangions are

used in snap-on systems (Leach 1998). The gangions are

snapped to the mainline as it pays off a drum, and removed

and rebaited when the wire is hauled. In New England,

longlines are usually set for only a few hours at a time in

areas with attached benthic epifauna. Longlines used for

tilefish are deployed in deep water, may be up to 40 km (25

mi) long, are stainless steel or galvanized wire, and are set in

a zigzag fashion .

These activities are managed under federal FMPs.

PELAGIC GEAR

Mid-Water Trawls

Mid-water trawls are used to capture pelagic species

throughout the water column. For nets used on single

boats, the net is spread horizontally with two large metal

doors positioned in front of the net. A common type of

type of mid-water trawls used in the Atlantic herring and

Atlantic mackerel fisheries is the “rope” trawl. The forward

portion of these nets is constructed of a series of ropes that

extend back to very large meshes in the forward portion of

the net that become progressively smaller toward the rear

of the net. In the second type of net, instead of ropes, the

large meshes begin immediately in the forward portion of

the net. The large opening of the net functions to “herd”

schooling fish toward the rear of the net (see

www.gma.org, the website of the Gulf of Maine Research

Institute). Once the net is deployed, changes in its position

in the water column (height above the bottom) are made by

increasing or decreasing the speed of the vessel or by

bringing in or letting out trawl wire (NOAA/NMFS 2005).

An electronic sonar system mounted in the mouth of the

net allows the fisherman to continually monitor the size of

the net opening and the height of the net above the bottom

during each tow. In most cases, two heavy weights (e.g.,

“balls”of heavy chain each weighing 1000-5000 pounds)

are attached forward of the net to cables that extend from

the net opening to the trawl doors. This is done while

fishing in deep water to get the net closer to the bottom

without using as much trawl wire. Schools of fish are

located by means of directional sonar systems. Midwater trawls may occasionally contact the bottom if the

target species remain near the bottom (NOAA/NMFS

2005).

Tows typically last for several hours and catches are

large. The fish are usually removed from the net while it

remains in the water alongside the vessel by means of a

suction pump. In some cases, the fish are removed from the

net by repeatedly lifting the cod end aboard the vessel until

the entire catch is in the hold.

The use of mid-water trawls is managed under federal

FMPs.
Page 52

Paired Mid-Water Trawls

Mid-water trawls that are towed by two vessels are

called “pair” trawls. Pair trawls used in the Atlantic herring

fishery are designed identically as single boat mid-water

trawls, but do not have doors, since the net is spread by the

two vessels. Pair trawls are also used to catch Atlantic

mackerel (Table 3.1). The nets can be towed more

efficiently by two vessels because of their combined

towing power and because there are no doors. Pelagic pair

trawling has proved particularly successful in catching fish

schooling near the surface or in shallower areas where

noise from the two vessels herds fish into the path of the

net. Noise produced by a single vessel as it passes over a

school of fish (especially herring, which are very sensitive

to underwater sound) often causes fish to escape capture.

Pelagic pair trawls may occasionally contact the bottom

(NOAA/NMFS 2005).

Pelagic pair trawling is managed under federal FMPs.

Purse Seines

The purse seine is a deep, nylon-mesh net with floats

on the top and lead weights on the bottom. Rings are

fastened at intervals to the leadline, and a purseline runs

completely around the net through the rings. A school of

fish is encircled with the net, then the net is pursed by

drawing in a cable that runs through all the rings until the

fish are forced to the surface and into a small enough

pocket in the net that they can be transferred to the vessel.

Purse seines vary in size according to the species fished,

the mesh size, the size of the vessel, and the depth to be

fished. Purse seines are currently used in the Northeast

Region to catch Atlantic herring, Atlantic menhaden, and

several species of tuna.

In the herring fishery, one end of the net remains in the

vessel and the other end is attached to a power skiff that is

deployed from the stern of the vessel and remains in place

while the vessel encircles a school of fish with the net.

Most purse seines used in the New England herring fishery

range from 30 to 50 m deep (NOAA/NMFS 2005). If the

depth of the net exceeds the depth of the water where it is

set, the leadline can contact the bottom when the nets are

first set out, before they are “pursed.” Purse seining is a

year-round pursuit in the GOM, but is most active in the

summer when herring are more abundant in coastal waters.

It is done at night, when herring are feeding near the

surface. This fishing technique is less successful when

fish remain in deeper water and when they do not form

“tight” schools. Herring fishermen rely on directional

sonar systems to locate schools of fish.

In the menhaden fishery, small airplanes are used to

locate schools of menhaden. When a school is located,

two purse boats, each carrying half of the net, encircle the

school and close the net. The mother ship then comes

alongside and pumps the fish aboard. A few small vessels

have only one purse boat. The typical menhaden purse

seine net ranges in length from 300 to 430 m (980 to 1410 ft),

and is 20-27 m (66-89 ft) deep (ASMFC 1999b).

Use of herring and tuna purse seines is managed under

federal FMPs, but the menhaden fishery is managed by the

ASMFC.

Drift Gill Nets

Drift gill nets are designed to float from the sea surface

and extend downward into the water column, and are used

to catch pelagic fish. In this case, the buoyancy of the

floatline exceeds the weight of the leadline. Drift gill nets

may be anchored at one end or set out to drift, usually with

the fishing vessel attached at one end. This gear does not

come in contact with the bottom.

The use of drift gill nets is managed under federal

FMPs.

Pelagic Longline Gear

Pelagic or subsurface longlining is a technique used

mostly in the open ocean to catch highly migratory species

of tuna, swordfish, and sharks. The gear is typically set at

depths from the surface to around 330 m (1080 ft). It can

also be set with a mainline hanging in arcs below buoy

droplines to fish a series of depths. The length of the

mainline can be up to 108 km (67 mi), depending on the size

of the vessel. If the mainline is set at a fixed depth, then the

leader (i.e., gangion) lengths vary from 2 to 40 m (7 to 131

ft), thus ensuring that the hooks are distributed over a

range of depths. If a line-shooter is used to set the mainline

in a catenary shape, then the gangions are usually a single

minimal length, thus again ensuring that the hooks are

distributed over a range of depths. Each gangion typically

contains a baited hook and chemical night stick to attract

the fish. Traditional or circle hooks may be used.

Swordfish vessels typically fish 20-30 hooks per 1.6 km (1

mi) of mainline, which is between 5 and 54 km (3 and 34 mi)

long. This gear does not contact the bottom.

The use of pelagic longlines to catch highly migratory

species is regulated by the National Marine Fisheries

Service (NMFS).

Troll Lines

Trolling involves the use of a baited hook or lure

maintained at a desired speed and depth in the water.

Usually, 2-4 or even more lines are spread to varying widths

by the use of outrigger poles connected to the deck by

hinged plates. Line retrieval is often accomplished by

means of a mechanized spool. Each line is weighted to

reach the desired depth and may have any number of

leaders attached, each with a hook and bait or an
Page 53

appropriate lure. Troll lines are used to catch a variety of

pelagic species in the region, including king mackerel

(Table 3.1). This gear does not contact bottom habitats.

This activity is managed under federal FMPs.

OTHER GEAR

Rakes

A bull rake is manually operated to harvest northern

quahogs (Mercenaria mercenaria), or hard clams, and

consists of a long shaft with a rake and basket attached.

The length of the shaft can vary, but usually does not

exceed three times the water depth. The length and spacing

of the teeth, as well as the openings of the basket, are

regulated to protect juvenile clams from harvest. Rakes are

typically fished off the side of a small boat. They are used

in estuarine waters throughout the region.

This activity is not managed under federal FMPs.

Tongs

Tongs are used to harvest shellfish in shallow water.

There are two principal types: shaft tongs and patent

tongs. Manually operated shellfish tongs are used in

nearshore and estuarine waters throughout the region,

primarily to harvest hard clams and eastern oysters.

Shaft tongs are a scissorlike device with a rake and

basket at the end of each shaft. The fisherman stands on

the edge of the boat and progressively opens and closes

the baskets on the bottom, gathering the shellfish into a

mound. The tongs are closed a final time, brought to the

surface, and the catch emptied on the culling board for

sorting. The length of the shaft must be adjusted for water

depth. Oysters are traditionally harvested with shaft tongs

in water depths up to 6 m (20 ft), with the shaft tongs

themselves being 8 m (26 ft) long.

Patent tongs are also used to harvest hard clams and

oysters. They are opened and closed with a drop latch or

with a hydraulic ram, and require a mechanized vessel with

a mast or boom and a winch.

This activity is not managed under federal FMPs.

Patent tongs are regulated by state fisheries agencies

according to weight, length of teeth, and bar spacing in the

basket.

Line Fishing

Hand Lines/Rod and Reel

The simplest form of hook-and-line fishing is the hand

line, which may literally be fished “by hand” or using a rod

and reel. The gear consists of a line, sinker, leader, and at

least one hook. The line is usually stored on a small spool

and rack and varies in length. The sinkers vary from stones

to cast lead. The hooks vary from single to multiple

arrangements in “umbrella” rigs. An attraction device must

be incorporated into the hook, usually a natural bait or an

artificial lure. Hand lines can be fished in such as manner as

to hit bottom and bounce, or to be carried by currents until

retrieved.

Hand lines and rods and reels are used in the

Northeast Region to catch a variety of demersal and pelagic

species (federally managed species are listed in Table 3.1),

including species of tuna, sharks, billfish, and swordfish.

This activity is managed under federal FMPs.

Mechanized Line Fishing

Mechanized line-hauling systems have been developed to allow more lines to be worked by smaller crews, and

to use electrical or hydraulic power to work the lines on the

spools or jigging machines. These reels, often termed

“bandits,” are mounted on the vessel bulwarks and have a

spool around which the mainline is wound. Each line may

have a number of branches and baited hooks, and the line is

taken from the spool over a block at the end of a flexible arm.

Hooks and sinkers can contact the bottom, depending

upon how the gear is used.

Jigging machine lines are generally fished in waters up

to 600 m (1970 ft) deep. Jigging refers to the action of

jerking a line with several unbaited hooks up in the water to

snag a fish in its body. Jigging is commonly used to catch

squid.

This gear is used to catch a variety of demersal and

pelagic species, including highly migratory species of tuna,

sharks, and swordfish. The use of this gear is managed

under federal FMPs.

Hand Hoes

Intertidal flats are harvested for baitworms (Glycera

dibranchiata and Nereis spp.) and softshell clams by

using handheld hoes. These hoes are short-handled,

rakelike devices that are often modified gardening tools

(Creaser et al. 1983). Baitworm hoes have 5-7 tines which

are 21-22 cm (8.3-8.7 in) long when used for bloodworms,

and which are 34-39 cm (13-15 in) long when used for

sandworms. Clam hoes in Maine typically have 4-5 tines

which are 15 cm (6 in) long (Wallace 1997).

This activity is not managed under federal FMPs.

Diving

Divers, either free diving or using SCUBA, harvest a

variety of benthic invertebrate species -- including sea

urchins, scallops, and quahogs -- in relatively shallow

coastal and inshore waters throughout the region. Often, a
Page 54

support vessel is used to transport the diver(s) to the

fishing site and carry the catch to shore. Divers often use

small rakes or hoes to scrape animals off rocks or dig them

out of the seafloor. Generally, the catch is placed in bags

that are either towed to the surface by the boat or floated to

the surface using an air source and a lift bag.

This activity is not managed under federal FMPs.

Spears and Harpoons

Spears with long shafts (gigs) are used by fishermen in

small boats to catch fish in shallow water, and by divers.

Harpoons are used offshore to fish for certain highly

migratory species.

The use of spears in state waters is not managed under

federal FMPs, but the use of harpoons in the tuna fishery is

managed by NMFS.
Page 55

Table 3.1. Percentage of landings (1% or more by weight) by fishing gear type for federally managed species and species groups in the Northeast Region in 2004. (Does not include highly migratory 

species, i.e., tuna, sharks, swordfish, and billfish.) 

Species and Species Groups 

Gear 

American Plaice 

Atlantic Cod 

Atlantic Halibut 

Atlantic Herring 

Atlantic Mackerel 

Atlantic Surfclam 

Barndoor Skate 

Black Sea Bass 

Bluefish 

Butterfish 

Clearnose Skate 

Cobia 

Goosefish 

Haddock 

Hake, Red & White 

King Mackerel 

Little Skate 

Longfin Inshore Squid 

Northern Shortfin 

Squid 

By hand Dip net Dredge, clam 6.6 Clam dredge, hydraulic Dredge, other 2.6 1.5 2.0 1.0 2.7 1.3 Dredge, sea scallop 2.1 Dredge, surfclam + ocean quahog 90.2 Gill net, drift 1.0 Gill net, fixed or anchored, sink 1.8 30.0 13.2 9.5 1.7 44.4 4.1 66.2 28.4 53.7 2.3 6.3 Gill net, other 2.5 5.6 Gill net, run-rround Gill net, set/stake 14.4 34.9 19.8 Handline 3.9 5.1 3.5 14.0 3.2 3.5 5.1 Haul seine, beach Haul seine, long Longline, bottom 1.6 3.9 3.3 1.6 Longline, pelagic 4.4 Pot/trap, lobster, inshore Pot/trap, lobster, offshore Pots + traps, crab, other Pots + traps, fish 3.7 Pots + traps, other 28.0 1.1 Pound net, fish 1.4 7.1 3.7 Pound net, other 1.0 1.2 1.4 1.1 2.2 1.2 Purse seine, herring 2.5 Purse seine, other 9.3 Rake, other 1.8 Trawl, otter, bottom, fish 92.5 58.5 60.3 29.8 8.8 41.8 13.8 69.3 32.3 1.3 35.8 82.4 21.0 98.2 83.3 93.4 Trawl, otter, bottom, scallop 1.4 Trawl, otter, bottom, other 2.0 2.0 2.4 Trawl, otter, midwater 30.0 43.0 2.4 1.2 3.4 Trawl, midwater, paired 25.1 38.1 2.2 Troll line, other 2.2 1.0 50.6 66.3 1.5 Troll and handline, combined 7.2 Unknown 4.4 3.0 20.7 100 10.2 14.8 13.4 1.5 4.6 4.3 4.5 5.4 5.7 4.4 
Page 56

Table 3.1. Percentage of landings (1% or more by weight) for federally managed species and species groups by fishing gear type in the Northeast Region in 2004. (Does not include highly migratory 

species, i.e., tuna, sharks, swordfish, and billfish.) 

Species and Species Groups 

Gear 

Ocean Pout 

Ocean Quahog 

Offshore Hake, 

Unclassified 

Pollock 

Red Deepsea Crab 

Red Drum 

Red Hake 

Redfish 

Rosette Skate 

Scup 

Sea Scallop 

Silver Hake 

Skates 

Smooth Skate 

Spanish Mackerel 

Spiny Dogfish 

Squids, Unclassified 

Summer Flounder 

Thorny Skate 

By hand 17.1 Dip net Dredge, clam Clam dredge, hydraulic 3.3 Dredge, other 3.9 2.4 56.7 11.2 1.3 Dredge, sea scallop 33.9 Dredge, surfclam + ocean quahog 96.6 Gill net, drift 1.4 Gill net, fixed or anchored, sink 37.5 7.9 4.2 2.9 17.7 97.6 3.4 75.1 1.3 46.7 Gill net, other 1.5 8.0 2.6 Gill net, run-around 3.3 Gill net, set/stake 79.8 79.2 Handline 12.2 2.3 4.5 2.2 1.5 Haul seine, beach 1.2 Haul seine, long 2.7 Longline, bottom 6.2 1.8 78.4 1.1 1.7 1.5 Longline, pelagic Pot/trap, lobster, inshore 3.0 1.6 Pot/trap, lobster, offshore Pots + traps, crab, other 18.7 Pots + traps, fish 7.1 Pots + traps, other 3.3 79.5 3.7 1.8 Pound net, fish 13.7 Pound net, other 13.7 6.2 Purse seine, herring Purse seine, other Rake, other Trawl, otter, bottom, fish 63.7 46.2 59.2 84.7 12.5 95.8 54.0 6.2 76.9 62.1 1.0 13.7 71.3 81.2 51.9 Trawl, otter, bottom, scallop 1.2 Trawl, otter, bottom, other 1.2 1.9 Trawl, otter, midwater Trawl, midwater, paired Troll line, other 1.7 1.6 Troll and handline, combined Unknown 2.9 32.0 1.1 10.2 3.2 15.8 1.5 10.4 3.7 1.1 1.6 23.6 7.5 
Page 57

Table 3.1. Percentage of landings (1% or more by weight) for federally managed species and species groups by fishing gear type in the Northeast Region in 2004. (Does not include highly migratory 

species, i.e., tuna, sharks, swordfish, and billfish.) 

Species and Species Groups 

Gear 

Tilefish 

White Hake 

Windowpane 

Winter Flounder 

Winter Skate 

Witch Flounder 

Yellowtail 

ALL SPECIES 

By hand 0.05 Dip net 1.0 0.02 Dredge, clam 0.56 Clam dredge, hydraulic 0.18 Dredge, other 1.6 5.78 Dredge, sea scallop 3.03 Dredge, surfclam + ocean quahog 12.82 Gill net, drift 0.01 Gill net, fixed or anchored, sink 6.5 24.2 1.5 4.6 9.7 1.2 2.8 5.87 Gill net, other 0.21 Gill net, run-around 0.00 Gill net, set/stake 0.23 Handline 3.6 0.35 Haul seine, beach 0.00 Haul seine, long 0.02 Longline, bottom 60.9 1.4 0.36 Longline, pelagic 0.00 Pot/trap, lobster, inshore 0.01 Pot/trap, lobster, offshore 0.03 Pots + traps, crab, other 0.10 Pots + traps, fish 0.04 Pots + traps, other 0.61 Pound net, fish 4.8 0.05 Pound net, other 1.6 9.5 0.68 Purse seine, herring 0.61 Purse seine, other 2.25 Rake, other 0.07 Trawl, otter, bottom, fish 19.2 71.5 91.2 76.2 82.7 89.8 81.7 35.81 Trawl, otter, bottom, scallop 0.19 Trawl, otter, bottom, other 0.39 Trawl, otter, midwater 14.29 Trawl, midwater, paired 12.16 Troll line, other 0.74 Troll and handline, combined 0.01 Unknown 9.4 2.3 3.9 6.6 6.9 7.1 8.1 2.41 
Page 58

Table 3.2. Percentage of landings for all species (1% or more of state total landings by weight) by fishing gear type for states in the Northeast Region in 2004 

STATE 

Gear ME NH MA RI CT NY NJ MD DE VA NC ALL By hand 4.6 Diving gear, urchins 1.7 Dredge, clam 11.1 Dredge, clam, hydraulic 6.6 Dredge, crab 9.5 Dredge, other 4.1 5.5 2.3 4.9 5.0 2.7 3.6 Dredge, oyster 1.8 Dredge, sea scallop 3.7 11.2 1.8 1.1 1.5 Dredge, surfclam + ocean quahog 6.6 2.7 6.5 5.5 33.0 14.7 6.5 Dredge, sea urchin 1.1 Dredge, whelk 10.4 Gill net, fixed or anchored, sink 1.4 14.5 8.2 3.8 1.7 3.6 2.8 1.3 2.6 15.0 Gill net, drift 1.5 5.3 4.1 Gill net, set/stake 10.0 10.5 Handline 1.0 1.2 1.4 Longline, bottom 3.1 Longline, pelagic 3.4 Pot/trap, lobster, inshore 23.6 1.5 2.9 3.8 Pot/trap, lobster, onshore, wire 3.7 Pot/trap, lobster, offshore 1.9 Pots + traps, blue crab 1.8 45.8 47.6 4.8 15.5 3.9 Pots + traps, eel 3.2 Pots + traps, other 1.7 1.1 2.7 2.4 2.1 1.1 Pots + traps, whelk 1.1 Pound net, fish 10.1 2.8 16.8 1.3 Pound net, other 1.1 1.5 4.0 Purse seine, herring 1.9 1.0 Purse seine, menhaden 6.8 73.7 25.2 Purse seine, other 7.4 1.0 8.1 Rakes, other 1.4 2.9 1.1 Tongs and grabs, other 3.2 Trawl, otter, bottom, fish 11.8 69.3 29.7 65.4 37.1 42.4 22.4 2.0 1.4 18.6 Trawl, otter, bottom, other 28.4 Trawl, otter, bottom, shrimp 1.0 1.5 3.6 Trawl, otter, midwater 17.5 3.7 15.8 3.6 7.6 7.3 Trawl, midwater, paired 4.1 5.9 16.6 6.7 12.2 6.2 Troll line, other 2.9 1.0 1.7 Trot line with bait 20.9 Unknown 17.4 2.4 6.0 28.2 18.6 2.9 4.8 
Page 59

Table 3.3. Fishing gears and techniques used in the Northeast Region, categorized by the waters in which they are used, by whether or not they 

contact the bottom, and by whether or not their use is regulated by federal FMPs. (Includes all gears that accounted for 1% or more of any 

state’s total landings, and all gears that harvested any amount of any federally managed species, based upon 2004 landings data and an 

ASMFC report on gear impacts to submerged aquatic vegetation (Stephan et al. 2000).) 

Water Type 

Gear Estuary or Bay Coastal (0-3 mi) Offshore (3-200 mi) Contacts Bottom Federally Regulated

By hand X X X

Diving X X X

Dredge, clam X X X X X

Dredge, crab X X X 

Dredge, mussel X X X 

Dredge, oyster X X 

Dredge, bay scallop X X 

Dredge, sea scallop X X X X

Dredge, sea urchin X X X 

Dredge, whelk X X 

Floating trap X X X X

Fyke and hoop net, fish X X X 

Gill Net, drift XX

Gill Net, run-around X X 

Gill Net, sink/anchor X X X X X

Gill Net, stake X X X X X

Handline X X X X

Haul seine, beach X X X 

Haul seine, long X X X 

Haul seine, long (Danish) X X X X

Hoe X X 

Longline, bottom X X X X

Longline, pelagic X X X

Otter trawl, bottom, crab X X X X 

Otter trawl, bottom, fish X X X X X

Otter trawl, bottom, scallop X X X X

Otter trawl, bottom, shrimp X X X X X

Otter trawl, midwater X X X

Pots and traps, crab, blue X X X 

Pots and traps, crab, other X X X X X

Pots and traps, eel X X X 

Pots and traps, fish X X X X X

Pots and traps, lobster, inshore X X X 

Pots and traps, lobster, offshore X X X

Pots and traps, whelk X X X 

Pound nets, crab X X X 

Pound nets, fish X X X 

Purse seines, herring X X X

Purse seines, menhaden X X

Purse seines, tuna X X X

Rakes X X 

Reel, electric or hydraulic X X X

Rod and reel X X X X

Scottish seine X X X X

Scrapes X X 

Spears X X X

Stop seines X X 

Tongs and grabs, oyster X X 

Tongs, patent, clam, other X X 

Tongs, patent, oyster X X 

Trawl, midwater, paired X X X

Troll line, other X X X

Trot lines, with bait X X X

Weirs X X 
Page 60

4. GEOGRAPHIC DISTRIBUTION OF FISHING ACTIVITY BY GEAR TYPE

The information in this section of the document was

compiled as part of an overall effort to determine the

potential effects of fishing on benthic marine habitats in the

Northeast Region. The objective of this information

compilation was to calculate the spatial distribution of

fishing activity by the principal gear types used in regional

commercial fishing operations. The data used in these

calculations were extracted from the NOAA Fisheries

Service fishing vessel trip report (FVTR) and clam logbook

databases for the years 1995-2001. The clam logbook

program was implemented in 1991, and the FVTR data

collection program in 1994, to monitor the geographic

distribution of catches of federally regulated species in the

region. Both data collection systems are mandatory, and

the data are collected by fishermen. This is the first time

that either of these databases has been utilized for

estimating the spatial distribution of fishing activity

throughout the region.

Previous attempts to determine the spatial distribution

of fishing activity in the Northeast Region have been

restricted to a single gear type -- bottom otter trawls -- and

have described trawling activity that occurred during the

mid-1980s and early 1990s, before the closing of three areas

on Georges Bank to all gear used to catch groundfish,

including bottom trawls and scallop dredges. These

closures, which were implemented in December 1994 (see

Figure 4.1) as part of an overall effort to restore depleted

groundfish stocks, greatly affected the subsequent

distribution of trawling and dredging operations in the

region. Additional year-round groundfish closures (also

shown in Figure 4.1) were established in the western GOM

in May 1998, and in the vicinity of Cashes Ledge in the

central GOM in August 2001.

Earlier analyses of bottom trawling activity in the

region relied on information collected by NOAA Fisheries

Service port agents who interviewed fishermen after their

vessels returned to port. Interviews were conducted for

about 60% of all trips. Data from interviewed trips included

the number of days (to the nearest 0.1 day) that a vessel

trawled in each 10' “square” (TMS) of latitude and

longitude. (A TMS represents 10' (i.e., one-sixth of a

degree) of latitude along each side, and 10' of longitude

along the top and bottom. Because of the curvature of the

earth’s surface, TMSs north or south of the Equator are

actually rectangles that diminish in size as the meridians of

longitude converge at the poles. Within the range of

latitudes in the Northeast Region, TMSs range in size from

109.65 km2

 in the south to 94.20 km2 in the north. Because

the projection used to display the FVTR and clambook data

in this document is a Mercator projection, the TMSs in

Figures 4.2-4.13 appear to be the same size.) Interview

information (average numbers of days fishing per trip) was

applied to the noninterviewed trips, but the estimated

fishing time for these trips was assigned to 30' squares.

(One 30' square is one-half of a degree of latitude and

longitude on each side, and contains nine TMSs.)

Churchill (1989) used data from all trips made in 1985 to

estimate the percentage of area trawled in individual 30'

squares between Cape Cod and North Carolina, using an

average trawl width (door to door, while underway) of 40 m,

and an average towing speed of 5.5 km/hr. These same

methods were applied to data collected by port agents in

1993 for Georges Bank and the GOM (analysis by Churchill

in NRC 2002).

A more recent analysis of 1991-1993 data for

interviewed and noninterviewed bottom trawl trips was

prepared for a National Research Council report on

trawling and dredging effects (NRC 2002). In this case, the

results for 10' and 30' squares were combined in one map,

and displayed as low, medium, and high numbers of days of

fishing per 10' square. No attempt was made to estimate the

area swept by the gear within each square. This analysis

was flawed by the fact that the extrapolated 30'-square

fishing effort estimates were assigned to the single 10'

square at the center of each 30' square. This biases the

results and produces a “checkerboard” effect in the mosaic

of 10' squares.

METHODS

Data Analysis

The geographic distribution of fishing activity during

1995-2001 was calculated by TMS for 12 commonly used,

bottom-tending gear types in the Northeast Region. Data

reported south of Cape Hatteras (35°N) and north of 45°N

latitude in the GOM were excluded from analysis. Data for

gear used mostly in state waters and/or for gear that is not

well represented in the FVTR or clam logbook databases

(e.g., mussel and sea urchin dredges, nonhydraulic quahog

dredges, Danish seines, shrimp pots) or for gear that does

not normally contact the bottom (e.g., purse seines, midwater trawls, pelagic longlines, floating gill nets) were not

analyzed.

The FVTR and clam logbook data are provided by

vessels operating with federal permits and participating in

the following fisheries: Northeast multispecies, sea

scallop, surf clam and ocean quahog, goosefish, summer

flounder, scup, black sea bass, squid, Atlantic mackerel,

butterfish, spiny dogfish, bluefish, Atlantic herring, and

tilefish. There is no requirement for vessels permitted in

just the offshore lobster fishery to report or log their

activities. However, vessels permitted in both the offshore

lobster and Northeast multispecies fisheries must report on

their lobster fishing activity. Consequently, the data for

lobster pots were provided by those vessels with

multispecies and offshore lobster permits.
Page 61

Vessels that operate strictly within state waters (0-3 mi

from shore) are not required to have a federal permit, and

therefore do not submit trip reports. For this reason,

fishing trips in nearshore TMSs that include a significant

proportion of state waters are under-represented in the

data.

Permit holders are required to fill out a FVTR form or

make a logbook entry for each trip made by the vessel (i.e.,

each time the vessel leaves and returns to port). Fishermen

report the general location where most of their fishing effort

occurs during a trip, and the date and time that the vessel

leaves and returns to port. (Fishermen are also asked to

answer questions regarding the quantity and size of gear

used during a trip, how many tows or sets were hauled, and

what was the average tow or soak time. However, because

this information is either not reported at all, or is reported in

an inconsistent manner, it is not reliable and was not used

in this analysis.) Fishermen are also given the choice of

reporting the location of a trip as a point (i.e., latitude and

longitude) or simply assigning it to a statistical area (these

areas are quite large and include many TMSs). Only trips

that were reported as a point location and therefore could

be assigned to a TMS were included in this analysis. Most

trips are reported this way, but not all (Table 4.1).

For most of the analyzed, mobile, bottom-tending gear

(i.e., scallop dredges and three types of otter trawl), fishing

activity was calculated as the total number of days absent

from port during the 7-yr period. Days absent for each

scallop dredge and otter trawl trip were calculated based on

the date and time of departure from, and return to, port in

hours, and were then converted to fractions of 24-hr days.

Days-absent calculations for trawl and scallop dredge

vessels are clearly preferable to simply summing the

number of trips, but overestimate actual fishing time since

they include travel time and any other non-fishing-related

activity while the vessels are away from port. For clam

dredges, fishing activity was calculated as the actual hours

spent fishing during the 7-yr period, and was then

converted to fractions of 24-hr days. For fixed gear (i.e.,

bottom longlines, sink gill nets, and five types of pots),

fishing activity was calculated as the total number of trips

during the 7-yr period.

This method of compiling the data by TMS was

considered to be preferable to plotting individual trip

locations as point data, since many trips, especially for

vessels using mobile gear, last for many days and can

extend over fairly large areas. For these trips, even data

compiled by TMS only approximate the actual spatial

distribution of fishing activity throughout the region. For

trips of shorter duration that do not extend over large areas,

the figures in this document are more representative of

actual fishing activity distributions. For this reason, and

because some fishing trips in the FVTR database are not

assigned to a point location and could not be included in

this analysis, the values associated with each TMS are not

provided in this document.

Data Portrayal

The calculated data have been portrayed in Figures

4.2-4.13 using geographical information systems (GIS)

software (ArcView 3.2, ESRI, Inc.). These geographic

portrayals of the relative nature of fishing activity for each

gear type were achieved by ranking the TMSs in order from

those with the most fishing activity to those with the least

activity. TMSs were categorized according to the

cumulative percentage of the overall activity (i.e., the total

number of days or trips during the 7-yr time period) which

they represented.

Those TMSs which had the most activity and which

cumulatively accounted for 50% of the overall activity were

assigned to a “high” or 50th percentile category. Those

TMSs which cumulatively accounted for the next 25% of

overall activity were assigned to a “medium” or 75th

percentile category. Those TMS which cumulatively

accounted for the next 15% of overall activity were

assigned to a “low” or 90th percentile category. For the 9 of

the 12 gear types that had <100,000 trips or days of fishing

reported during the 7-yr period, just the 50th, 75th, and 90th

percentile categories were portrayed. For the three gear

types that had >100,000 trips or days of fishing reported

during the 7-yr period, the 95th percentile category was

also portrayed. Exclusion of extreme “low end” data (i.e.,

those TMSs which would fall into a higher percentile

category than 90th or 95th, as appropriate) eliminated a

large number of spatially misreported trips from the figures.

Fishing activity categories in the figures are labeled

according to the range in the number of days or trips that

were reported within each TMS. Tables 4.2 and 4.3 show

the ranges, the total amount of fishing activity represented

by all the TMSs in each category, and the total amount of

fishing activity (100% of the frequency distribution of days

or trips) throughout the region for each gear type.

RESULTS

Bottom Otter Trawls -- Fish

Most of the reported otter trawl activity during 1995-

2001 was directed at the capture of fish (Figure 4.2) rather

than shrimp or scallops (Figures 4.3 and 4.4). There was

more than twice as much fishing activity reported for this

gear than for scallop dredges (Table 4.2). Bottom otter

trawling for fish was widespread in coastal and offshore

waters throughout most of the Northeast Region, easily

accounting for more TMSs than any other gear (Figure

4.14). Areas of highest activity were located in

southwestern and central portions of the GOM, along the

western side of the Great South Channel (east of Cape

Cod), north of Closed Area I and on the northern part of

Georges Bank west of Closed Area II, in coastal waters of

Rhode Island and Long Island, in the mid-shelf region of
Page 62

Southern New England, and along the edge of the shelf,

especially along the 40th parallel of N latitude between 70o

and 73o W longitude and in the Hudson Canyon area.

Bottom trawling was prohibited in the three groundfish

closed areas on Georges Bank during the entire 1995-2001

period, and was absent, or nearly so, in a large area of the

continental shelf off southern New Jersey, Maryland, and

Virginia. The distribution of fish trawling activity among

TMSs within the range fished by this gear was intermediate

[i.e., it was neither heavily concentrated nor widely

dispersed (Figure 4.15)].

Bottom Otter Trawls -- Shrimp

Shrimp trawling was localized in two areas: the coastal

waters of the GOM between Cape Ann and Penobscot Bay,

and in nearshore waters of North Carolina, particularly

inside the barrier islands (Figure 4.3). Shrimp trawling was

reported within a relatively small number of TMSs (Figure

4.14), and was evenly distributed among those TMSs

(Figure 4.15). The total number of reported days at sea was

also fairly low (Table 4.2).

Bottom Otter Trawls -- Sea Scallops

Scallop trawling was conducted on the outer MidAtlantic shelf, primarily between 40o and 37oN (Figure 4.4).

The total number of reported days absent from port and the

total number of “populated” TMSs were low (Table 4.2;

Figure 4.14). Scallop trawling was concentrated in a small

proportion of the total number of TMSs where this gear

was used (Figure 4.15).

Scallop Dredges

Scallop dredges were used primarily in a broad area of

the Mid-Atlantic shelf from Long Island to Virginia, in

Massachusetts Bay (north of Cape Cod) and the Great

South Channel, in localized TMSs on Georges Bank

northeast of Closed Area I and west of the northern portion

of Closed Area II, and in a larger area on the southeast flank

of the bank that included the southern portion of Closed

Area II that was opened to limited scallop dredging in 1999

(Figure 4.5). Some scallop dredging was also reported from

eastern Maine coastal waters. No active scallop dredging

was reported in shallow open areas on Georges Bank, in

Southern New England, nor in inner shelf waters of the

MAB. Some scallop dredging also occurred in portions of

the other two closed areas on Georges Bank that were

temporarily opened to this gear during 1995-2001.

Compared to the other gear types, the number of TMSs

with reported scallop dredging covered an area of

intermediate size (Figure 4.14), and fishing activity was

fairly evenly distributed among TMSs (Figure 4.15).

Hydraulic Clam Dredges

The largest area of intensive hydraulic clam dredging

activity was located off the central New Jersey coast, with

smaller areas extending north and east to Southern New

England and south to the Delmarva Peninsula (Fig. 4.6).

The total number of TMSs within which clam dredging took

place during 1995-2001 was low (Figure 4.14), and fishing

was concentrated in a relatively small proportion of those

TMSs (Figure 4.15).

Bottom Longlines

Longline trips during 1995-2001 were reported

primarily in TMSs in the western GOM (Massachusetts

Bay) and along the western side of the Great South Channel

(Figure 4.7). A few trips were reported in deep water along

the edge of the shelf, in Rhode Island and central Maine

coastal waters, and in offshore locations of the GOM. The

total number of TMSs within which bottom longlines were

used was relatively low (Figure 4.14), and fishing was

evenly distributed among those TMSs (Figure 4.15).

Bottom Gill Nets

Bottom gill net trips were reported in the western GOM

and along the western side of the Great South Channel,

extending as far north as Cape Ann and Jeffreys Ledge, and

in a few TMSs in the outer gulf (Figure 4.8). Gill nets were

also used in Rhode Island coastal waters, along the outer

shore of Long Island, off northern New Jersey, the

Delmarva Peninsula, and in North Carolina. Gill net fishing

activity was highest in the western GOM and the Great

South Channel in areas that were also actively fished with

longlines, bottom trawls, and scallop dredges. The total

area fished, as represented by TMSs within which any

amount of fishing activity was reported, was relatively

large (Figure 4.14), and fishing was well distributed among

those TMSs (Figure 4.15).

Lobster Pots

The lobster pot fishery is the most active fixed-gear

fishery in the Northeast Region. During 1995-2001, there

were almost three times as many trips reported for this gear

than for bottom gill nets, the second-most actively used

bottom-tending fixed gear (Table 4.3). Fishing activity for

this gear is under-reported to a greater degree than for the

other gears because nonfederally permitted vessels (which

are active in this fishery) are not required to submit reports.

Lobster pot trips were reported primarily in coastal waters

of the GOM from the Canadian border to Cape Cod, in

Rhode Island coastal and inner-shelf waters, and in the

New York Bight (Fig. 4.9). Fewer trips were made to more
Page 63

offshore locations in Southern New England, along the

edge of the shelf, on eastern Georges Bank, and along the

U.S.-Canada border north of the bank. Lobster pots were

deployed in a very large number of TMSs within the region

(Figure 4.14), and because of the large number of lowactivity TMSs (which are not shown in Figure 4.9), their use

was very evenly distributed among those TMSs (Figure

4.15).

Fish Pots

Most fish pot trips were reported on the south shore of

Massachusetts and Rhode Island, Long Island, and off

southern New Jersey, Delaware, and Maryland (Fig. 4.10).

Other areas where fewer trips were reported were located

on Jeffreys Ledge in the western GOM, east of Long Island

and south of Nantucket and Martha’s Vineyard, along the

outer edge of the continental shelf in the southern MAB,

and off the entrance to Chesapeake Bay. Fish pot trips

were reported from a small number of TMSs during 1995-

2001 (Figure 4.14), and the even-ness of their distribution

among TMSs was intermediate between the heavily

concentrated (e.g., crab and hagfish pots) and more evenly

dispersed (e.g., lobster pots) fixed gears (Figure 4.15).

Whelk Pots

Most fishing activity was reported in Nantucket

Sound and inshore waters of southern Massachusetts, in a

single TMS south of Rhode Island, and in coastal waters of

southern New Jersey and the Delmarva Peninsula,

extending south to North Carolina (Fig. 4.11). Fishing with

this gear was reported within a very small number of TMSs

(Figure 4.14), and was less evenly distributed among TMSs

than fishing with fish pots, but more evenly distributed

than crab or hagfish pot trips (Figure 4.15).

Crab Pots

Crab pot trips were reported in a small number of TMSs

in deep water along the edge of the shelf from eastern

Georges Bank all the way to Cape Hatteras, in a single TMS

south of Nantucket, in several nearshore locations in the

GOM, Nantucket Sound, Cape May , and in inshore waters

behind the North Carolina barrier islands (Fig. 4.12). Very

few trips were reported (Table 4.3). Fishing was very spread

out among a few isolated TMSs (Figure 4.14), but was

highly concentrated within those few TMSs (Figure 4.15).

Hagfish Pots

Hagfish pots were used exclusively in the southwestern GOM, in both shallow and deep water (Figure 4.13).

Only a few trips were reported within a small number of

TMSs (Table 4.3; Figure 4.14), and fishing activity was very

un-evenly distributed among TMSs (Figure 4.15).
Page 64

Table 4.1. Total number of trips by gear type in the FVTR database for 1995-2000, before and after removing trips 

that did not meet the criteria established for analysis (see text), and the percentage of analyzed trips 

(information for 2001 was not available) 

Gear Type Reported Trips Analyzed Trips Percent Analyzed

Bottom gill net 86,580 66,096 76.3 

Bottom longline 18,261 13,614 74.6 

Lobster pot 241,725 171,564 71.0 

Fish pot 13,323 9,779 73.4 

Crab pot 1,609 1,050 65.3 

Whelk pot 2,448 1,700 69.4 

Bottom otter trawl (fish) 218,668 174,617 79.9 

Bottom otter trawl (shrimp) 43,353 30,865 71.2 

Bottom otter trawl (scallops) 1,952 1,702 87.2 

Scallop dredge 32,248 23,206 72.0 

TOTAL 660,167 494,193 74.8 
Page 65

Table 4.2. Fishing activity reported by federally-permitted fishing vessels using mobile, bottom-tending gears in the 

Northeast Region (35-45oN) during 1995-2001. (Data shown as ranges in number of 24-hr days per 10

square (TMS) of latitude and longitude, and as cumulative number of 24-hr days (in parentheses), 

associated with percentiles of total reported fishing activity that are mapped in Figures 4.2-4.6. Number 

in last column is the total number of days at sea in all TMSs in the region for that gear type, as calculated 

from the time absent from port for each reported trip. Note: Not all trips in fishing vessel trip database 

could be assigned to TMSs (see Table 4.1).) 

Percentile of Fishing Activity Gear Activity 

Metric 50% 75% 90% 95% 100% 

Otter trawls (fish) Days absent 

from port 

603-5,058 

(175,907) 

333-602 

(263,176) 

136-331 

(315,582) 

63-135 

(333,105) 348,841 

Otter trawls 

(shrimp) 

Days absent 

from port 

409-1,677 

(11,837) 

137-399 

(17,986) 

32-136 

(21,591) --- 23,891 

Otter trawls 

(scallops) 

Days absent 

from port 

183-653 

(5,888) 

66-175 

(8,816) 

16-66 

(10,596) --- 11,720 

Scallop dredges Days absent 

from port 

732-3,371 

(78,831) 

338-724 

(118,850) 

95-333 

(142,493) 

34-93 

(150,392) 157,507 

Hydraulic clam 

dredges Days fishing 133-517 (8,027) 

64-126 

(11,990) 

31-63 

(14,412) --- 15,951 

Table 4.3. Fishing activity reported by federally-permitted fishing vessels using fixed gear in the Northeast Region 

(35-45oN) during 1995-2001. (Data shown as ranges in number of trips per 10square (TMS) of latitude 

and longitude, and as cumulative number of trips (in parentheses) associated with percentiles of total 

reported fishing activity that are mapped in figures 4.7-4.13. Number in last column is the total number 

of trips reported in all TMSs in the region for that gear type. Note: Not all trips in fishing vessel trip 

database could be assigned to TMSs (see Table 4.1).) 

Percentile of Fishing Activity Gear Activity 

Metric 50% 75% 90% 95% 100% 

Bottom 

longlines Trips 412-1,269 (8,211) 

129-314 

(12,345) 

11-126 

(14,914) --- 16,483 

Bottom gill nets Trips 520-3,831 

(43,194) 

167-511 

(65,220) 

50-167 

(78,156) --- 86,403 

Lobster pots Trips 2,084-10,895 

(115,726) 

816-2,009 

(173,326) 

161-759 

(208,362) 

45-160 

(219,906) 230,300 

Fish pots Trips 120-434 

(4,740) 

41-118 

(7,088) 

9-39 

(8,523) --- 9,423 

Whelk pots Trips 109-260 

(1,172) 

21-86 

(1,859) 

8-20 

(2,235) --- 2,471 

Crab pots Trips 89-227 

(678) 

13-44 

(1,093) 

2-13 

(1,312) --- 1,450 

Hagfish pots Trips 50-323 

(1,202) 

22-49 

(1,822) 

8-21 

(2,195) --- 2,430 
Page 66

Figure 4.1. Location of five year-round groundfish closed areas in the Gulf of Maine - Georges Bank region. (Cashes = Cashes Ledge;

WGOM = western Gulf of Maine; NLSCA = Nantucket Lightship Closed Area; CA1 = Closed Area I; and CA2 = Closed Area

II.)

NLSCA

CA1 CA2

Cashes

WGOM

71°0'0"W

71°0'0"W

70°0'0"W

70°0'0"W

69°0'0"W

69°0'0"W

68°0'0"W

68°0'0"W

67°0'0"W

67°0'0"W

40°0'0"N 40°0'0"N

41°0'0"N 41°0'0"N

42°0'0"N 42°0'0"N

43°0'0"N 43°0'0"N

44°0'0"N 44°0'0"N

NLSCA

CA1 CA2

Cashes

WGOM

71°0'0"W

71°0'0"W

70°0'0"W

70°0'0"W

69°0'0"W

69°0'0"W

68°0'0"W

68°0'0"W

67°0'0"W

67°0'0"W

40°0'0"N 40°0'0"N

41°0'0"N 41°0'0"N

42°0'0"N 42°0'0"N

43°0'0"N 43°0'0"N

44°0'0"N 44°0'0"N
Page 67

Figure 4.2. Bottom otter trawl (fish) fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a

high (50% cumulative), medium (75% cumulative), low (90% cumulative), or very low (95% cumulative) category of fishing

activity level (i.e., number of 24-hr days absent from port). See the text for further explanation of cumulative percentages, or

“percentiles,” and Table 4.2 for the ranges of fishing activity associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Days At Sea

603-5,058

333-602

136-331

63-135
Page 68

Figure 4.3. Bottom otter trawl (shrimp) fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either

a high (50% cumulative), medium (75% cumulative), or low (90% cumulative) category of fishing activity level (i.e., number

of 24-hr days absent from port). See the text for further explanation of cumulative percentages, or “percentiles,” and Table

4.2 for the ranges of fishing activity associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Days At Sea

409-1,677

137-399

32-136
Page 69

Figure 4.4. Bottom otter trawl (scallop) fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either

a high (50% cumulative), medium (75% cumulative), or low (90% cumulative) category of fishing activity level (i.e., number

of 24-hr days absent from port). See the text for further explanation of cumulative percentages, or “percentiles,” and Table

4.2 for the ranges of fishing activity associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Days At Sea

183-653

66-175

16-66
Page 70

Figure 4.5. Scallop dredge fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a high (50%

cumulative), medium (75% cumulative), low (90% cumulative), or very low (95% cumulative) category of fishing activity

level (i.e., number of 24-hr days absent from port). See the text for further explanation of cumulative percentages, or

“percentiles,” and Table 4.2 for the ranges of fishing activity associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Days At Sea

732-3,371

338-724

95-333

34-93
Page 71

Figure 4.6. Hydraulic clam dredge fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a high

(50% cumulative), medium (75% cumulative), or low (90% cumulative) category of fishing activity level (i.e., number of 24-

hr days of fishing). See the text for further explanation of cumulative percentages, or “percentiles,” and Table 4.2 for the

ranges of fishing activity associated with each cumulative percentage category.)

Days Fished

133-517

64-126

31-63

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°
Page 72

Figure 4.7. Bottom longline fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a high (50%

cumulative), medium (75% cumulative), or low (90% cumulative) category of fishing activity level (i.e., number of trips). See

the text for further explanation of cumulative percentages, or “percentiles,” and Table 4.3 for the ranges of fishing activity

associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Number of Trips

412-1269

129-314

11-126
Page 73

Figure 4.8. Bottom gill net fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a high (50%

cumulative), medium (75% cumulative), or low (90% cumulative) category of fishing activity level (i.e., number of trips). See

the text for further explanation of cumulative percentages, or “percentiles,” and Table 4.3 for the ranges of fishing activity

associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Number of Trips

520-3,831

167-511

50-167
Page 74

Figure 4.9. Lobster trap or pot fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a high

(50% cumulative), medium (75% cumulative), low (90% cumulative), or very low (95% cumulative) category of fishing

activity level (i.e., number of trips). See the text for further explanation of cumulative percentages, or “percentiles,” and

Table 4.3 for the ranges of fishing activity associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Number of Trips

2,084-10,895

816-2,009

161-759

45-160
Page 75

Figure 4.10. Fish pot fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a high (50%

cumulative), medium (75% cumulative), or low (90% cumulative) category of fishing activity level (i.e., number of trips). See

the text for further explanation of cumulative percentages, or “percentiles,” and Table 4.3 for the ranges of fishing activity

associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Number of Trips

120-434

41-118

9-39
Page 76

Figure 4.11. Whelk pot fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a high (50%

cumulative), medium (75% cumulative), or low (90% cumulative) category of fishing activity level (i.e., number of trips). See

the text for further explanation of cumulative percentages, or “percentiles,” and Table 4.3 for the ranges of fishing activity

associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Number of Trips

109-260

21-86

8-20
Page 77

Figure 4.12. Crab pot fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a high (50%

cumulative), medium (75% cumulative), or low (90% cumulative) category of fishing activity level (i.e., number of trips). See

the text for further explanation of cumulative percentages, or “percentiles,” and Table 4.3 for the ranges of fishing activity

associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Number of Trips

89-227

13-44

2-13
Page 78

Figure 4.13. Hagfish pot fishing activity in the Northeast Region during 1995-2001. (Each TMS is associated with either a high (50%

cumulative), medium (75% cumulative), or low (90% cumulative) category of fishing activity level (i.e., number of trips). See

the text for further explanation of cumulative percentages, or “percentiles,” and Table 4.3 for the ranges of fishing activity

associated with each cumulative percentage category.)

36°

36°

38°

38°

40°

40°

42°

42°

44°

44°

76°

76°

74°

74°

72°

72°

70°

70°

68°

68°

66°

66°

Number of Trips

50-323

22-49

8-21
Page 79

Figure 4.14. Number of 10' squares (TMSs) within which any amount of fishing activity was reported (i.e., the 100th percentile) during

1995-2001 by gear type. (Note: Important to show because the maps stop at the 90th or 95th percentile, and do not show

the full extent of fishing activity (i.e., TMSs with just a small amount of activity, as well as TMSs with activity that is

misreported by fishermen). Key: drs = New Bedford-style scallop dredge; gns = sink gill net; hyd = hydraulic clam dredge;

llb = bottom longline; otc = otter trawl (scallop); otf = otter trawl (fish); ots = otter trawl (shrimp); ptc = pots & traps (crab);

ptf = pots & traps (fish); pth = pots & traps (hagfish); ptl = pots & traps (lobster); and ptw = pots & traps (whelk).)

Figure 4.15. Proportion of area fished [all 10' squares] at the 90th percentile, an index of how evenly distributed the days or trips were

among 10' squares, during 1995-2001 by gear type. (Note: For gears at the high end, most of the fishing activity was

concentrated in a relatively small percentage of the total area fished (aggregated), and for gears at the low end, fishing activity

was more evenly dispersed among TMSs. Key: drs = New Bedford-style scallop dredge; gns = sink gill net; hyd = hydraulic

clam dredge; llb = bottom longline; otc = otter trawl (scallop); otf = otter trawl (fish); ots = otter trawl (shrimp); ptc = pots

& traps (crab); ptf = pots & traps (fish); pth = pots & traps (hagfish); ptl = pots & traps (lobster); and ptw = pots & traps

(whelk).)

Pct Area of Fishing Activity at 90%

0

10

20

30

40

50

pth ptc otc hyd ptw otf ptf drs gns ots llb ptl

Gear

Pct of all TMS

Extent of Fishing Activity at 100%

0

500

1000

1500

2000

2500

otf ptl gns drs llb ots ptf hyd otc ptc ptw pth

Gear

Number of TMS
Page 80

5. REVIEW OF LITERATURE ON FISHING GEAR EFFECTS

Seventy-three publications were included in the geareffects literature review. An attempt was made to include

all available, relevant, English language scientific publications in order to determine the effects on benthic marine

habitat types of the principal commercial fishing gears used

in the Northeast Region. Habitat types were defined by the

predominant substrate. Gear types that were selected were

those that are currently used in the region, or those that are

used elsewhere but were judged to have similar effects as

gears that are used in the region. Gears that are used

strictly in state waters to harvest species that are not

federally managed were not included.

This review details individual scientific studies and

summarizes what is known about each combination of gear

and substrate type. Both peer-reviewed and non-peerreviewed publications were included, but the emphasis was

on the former. Information summarized in this review was

based, in all cases, on primary source documents. An

attempt was made to include all relevant publications

available through early 2002.

This document differs in several important ways from

other recent reviews of the gear-effects literature (Jennings

and Kaiser 1998; Auster and Langton 1999; Collie et al.

2000) and from recent broadscale assessments of the

effects of commercial fishing gear on benthic marine

habitats and ecosystems (Dayton et al. 2002; NRC 2002).

Rather than emphasizing general conclusions that apply to

combined gear types (e.g., “reduction of habitat complexity

by mobile bottom-tending gear”), this document provides

detailed summaries, in text and tabular format, of individual

studies of relevance to the Northeast Region. The

intention was to provide enough information in each

summary for the reader to understand where and how the

research was conducted and what the principal results

were. Each such summary table contains information on

location, depth, substrate, effects, recovery, and the

methodological approach. No attempt was made to

critically evaluate the research approach or the validity of

the results, unless there were issues (e.g., a failure to

replicate treatment sites, not enough samples) identified as

problems by the authors themselves. Most of the studies

summarized in this document were also summarized in less

detail in an earlier NMFS report that included gear types

not used in the Northeast Region (Johnson 2002).

METHODS

The review is organized by combinations of gear and

substrate types. Nine of the seventy-three reviewed

studies included information for more than one gear type,

or for one gear type in more than one substrate or study

area, and were therefore summarized in more than a single

gear/substrate category. In all, there were 80 descriptions

for seven gear types and five substrates (Tables 5.1-5.3).

Cases in which the effects of more than one gear type were

evaluated in a single study and could not be distinguished

were categorized as multiple gears. The same approach

was used for studies conducted in mixed substrates that

could not be defined as mud, sand, gravel/rock, or

biogenic.

Over half (65%) of the descriptions in this document

are for otter trawls and scallop dredges, and all but one are

for different kinds of mobile bottom-tending gears. Thirtyfour of the studies were done in sandy substrate, twelve in

mud, seven in different types of biogenic substrate, five in

gravel and rocky bottom, and twenty-two in mixed

substrate. Most studies were peer reviewed, and most

were published after 1990. Geographically, 21 were

conducted in the northeastern United States (North

Carolina to Maine), 19 elsewhere in North America (United

States and Canada), 28 in Europe and Scandinavia, and 12

in Australia and New Zealand.

Individual Studies

Within each gear/substrate subsection, individual

studies are described in one to two paragraphs that include

the following information, when available:

• citation (authors and date of publication)

• location of study

• depth

• substrate type and/or composition

• detailed information on gear used, especially for otter

trawls

• type of study (observational or experimental)

• whether experiments were set up to test for time and

location effects

• type(s) of organisms sampled (infauna versus

epifauna)

• duration and intensity of fishing (number of tows,

duration of each fishing event, total duration of

fishing disturbance, frequency of fishing events, etc.)

• timing of sampling or observations (how often, how

long before or after fishing, etc.)

• timing and frequency of sampling or observations to

determine recovery

• whether study was done in a commercially exploited

or unexploited area

• if unexploited, for how long and what gears were

excluded

Details that were not generally included were

descriptions of sampling gears and procedures, sample

processing information (e.g., the mesh size used to sieve

grab samples), taxonomic categories used (families, groups

of species, individual species), and data analysis

procedures (e.g., statistical tests). General conclusions,
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when they are included, were the own statements of the

respective study’s author(s); neither speculations regarding the study in question nor any restatements made by the

authors regarding anybody else’s research were included.

Results which are described as “significant” are results

that were statistically significant. To avoid confusion, the

term was not used in any other context.

Each gear/substrate category also includes a table

summarizing the setting (location, depth, and sediment

type), general methods, and primary results of each study.

The listing of results in these tables is divided into an

effects column and a recovery column. Results summarized

in the tables include positive and negative results (e.g.,

increases and decreases in abundance caused by fishing,

as well as instances when there were no detectable effects

of fishing). Blank cells in the recovery column indicate that

the study was not designed to provide information on

recovery times. Information in the last column includes the

nature of the research (experimental or observational),

whether or not the study area was being commercially

fished at the time of the study, and how the experimental

fishing was conducted (single or multiple tows, discrete or

repeated disturbance events, and, if known, the average

number of tows to which any given area of bottom was

exposed).

Summaries

This section also summarizes results for all studies

combined in each gear/substrate category. Each such

summary begins with an introductory paragraph that

includes general information, such as:

• the number of studies that examined physical and

biological effects

• how many studies were done in different geographic

areas and depth ranges

• how many studies examined recovery of affected

habitat features

• the number of studies performed in areas that were

closed to commercial fishing versus areas that were

commercially fished at the time of the study

• how many studies involved single versus multiple

tows

• how many studies were conducted either during a

single discrete time period or during a more prolonged

period of time that was intended to simulate actual

commercial fishing activity

Physical and biological effects for each gear/substrate

category are summarized in separate paragraphs. When

necessary, biological effects are presented separately for

single disturbance and repeated disturbance experimental

studies, and for observational studies.

RESULTS

Otter Trawls

Otter Trawls -- Mud (Table 5.4)

1. Ball et al. (2000) sampled benthic macrofauna

before and 24 hr after trawling at a heavily fished site within

an offshore prawn (Nephrops) trawl fishing ground in the

Irish Sea and at an unfished “pseudo-control” site near a

shipwreck at the same depth (75 m) that had not been fished

for about 50 yr. Sediments were sandy silt. No information

on the duration of experimental trawling or the type of net

used was provided.

Due to few organisms and low biomass, and to the

resulting high intersample variance, it was not possible to

quantitatively evaluate the short-term effects of trawling at

the fished site. There were, however, considerably fewer

species and individuals, and lower species diversity and

richness, in the commercially trawled area than near the

shipwreck.

At the shipwreck site, the number of species, number

of individuals, and biomass decreased with increasing

distance from the wreck. High intersample variance in

biomass estimates near the wreck impeded comparisons

with the trawled site. Sixty-nine species found at the wreck

site were not found at the experimental fishing site. These

included polychaetes, crustaceans, bivalve mollusks,

gastropods, and echinoderms. Large specimens of some

mollusks and echinoderms were most common near the

wreck, whereas only juveniles of these species were

sampled in the trawled area.

2. Brylinsky et al. (1994) examined physical and

biological effects of 18-24 m wide flounder trawls with 180-

270 kg doors, 29-cm-diameter rubber rollers, and no tickler

chains in an intertidal estuary in the upper Bay of Fundy,

Nova Scotia. The study area was commercially fished for

flounder by trawlers. Four trawling experiments were

conducted at two sites in 6-8 m of water (at high tide) in

1990 and 1991. Repeated tows were made during a single

day at each site, but not over the same bottom area.

Samples of macrobenthos, meiofauna, and chlorophyll

were collected at each site at variable intervals for 1.5-4 mo

after trawling. One site had sand overlain with several

centimeters of silt; the other site had siltier sediment to a

depth of at least 10 cm. The study area is a high-energy

environment, owing to the extreme tidal range (average 11

m with a maximum of 16 m) and tidal currents that frequently

exceed 2 knots.

Trawl doors made furrows 1-5 cm deep and berms that

were visible for at least 2-7 mo. The rollers compressed

sediments. The amount of disturbance varied markedly

and seemed to be influenced primarily by the kind of

sediment and the type of door used, being more
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pronounced in the finer sediments and when heavier doors

were used. Benthic diatoms (measured as chlorophyll a)

decreased in door furrows at some stations, but recovered

within 1-3 mo. No significant effects were observed on

macrobenthos, which was dominated by polychaetes. The

numbers of nematodes in door furrows were reduced, but

only for 1-1.5 mo, and may only have been displaced by the

doors. Benthic taxa such as mollusks, crustaceans, and

echinoderms that are known to be more susceptible to

trawling were not present in the study site.

3. DeAlteris et al. (1999) analyzed data from a 1995

sidescan sonar survey to locate and map trawl tracks in

shallow sand and mud sediments in lower Narragansett

Bay, Rhode Island. At the deeper (14-m) mud-bottom site,

trawl doors produced smooth tracks 5-10 cm deep with

berms on the inside edge that were 10-20 cm high.

The longevity of hand-dug trenches (dug to simulate

tracks left by trawl doors) was monitored using SCUBA

divers. The trenches were observed unchanged for the

duration of the study (>60 days), and were occupied by

Atlantic rock crabs. Natural erosion at this site was

predicted to occur <5% of the time.

4. Drabsch et al. (2001) used divers to sample benthic

infauna before and after experimental trawling in an area of

South Australia (Gulf of St. Vincent) where little or no

fishing had occurred for 15 yr. Three study sites were used

(one in mud and two in sand), with adjacent trawled and

control corridors at each site. (See “Otter Trawls -- Sand, 4.

Drabsch et al. (2001)” for a summary of results at the two

sandy study sites.) Two series of 10 adjacent tows were

made in a single trawl corridor at the mud treatment site

during 1 day in October 1999 using triple prawn trawls with

two doors (1x2 m, 200 kg each) and a combined sweep

length of about 20 m. Bottom sediments at the mud study

site were fine silt sediments and the depth was 20 m.

Trawl doors left tracks, and the footline and net

smoothed topographic features and removed 28% of the

epifauna (not differentiated between mud and sand

substrates). Remaining epifauna in the trawled corridor

showed signs of damage. Total infaunal abundance and

the abundance of one family of polychaetes (Ctenodrilidae)

were significantly reduced 1-wk after trawling. No

significant changes were evident for any other taxon.

5. Frid et al. (1999) examined the long-term effects of

fishing with prawn (Nephrops norvegicus) otter trawls by

comparing changes over 27 yr on macrobenthic communities at a lightly fished (LF) and a heavily fished (HF)

location off the northeastern coast of England (North Sea).

Fishing activity within the statistical area that includes

both sites was divided into three periods of low (1971-

1981), high (1982-1989), and moderate (1990-1997) fishing

effort. The depth at the HF site was 80 m, and the substrate

was predominantly (>50%) silt-clay. Grab samples were

collected at the HF site every year during January. Benthic

taxa in the samples were divided into two groups that were

predicted to respond negatively (i.e., decreased number of

individuals, or “abundance”) or positively (i.e., increased

abundance) to increased trawling activity, based on

published accounts.

The total abundance of taxa in the positive response

group conformed to predictions by increasing significantly

between the periods of low and high fishing effort, and

then declining when fishing effort dropped to moderate

levels. The total abundance of taxa in the negative

response group did not vary significantly between time

periods. Errant polychaetes were the only taxonomic group

in the negative response group to increase significantly at

high fishing effort. Starfish and brittle stars were more

abundant at high fishing effort, but not significantly. Sea

urchins, as predicted, decreased in abundance (to zero) at

high fishing effort. Sedentary annelids and large bivalve

mollusks were taxa in the negative response group that did

not decrease in abundance. Benthic macrofaunal

abundance at the HF site was low at the beginning of the

time series when phytoplankton production was also low,

but once fishing effort increased, there was no longer any

correlation between the two. (See “Otter Trawls -- Sand, 5.

Frid et al. (1999)” for a summary of results at the LF site that

had a sandy substrate.)

6. Hansson et al. (2000) examined the effects of

trawling on clay bottom habitats at 75-90 m depths in a

Swedish fjord. The benthic infauna was collected 1-5 mo

before trawling began at three experimental sites and three

control sites, and during the last 5 mo of a 1-yr trawling

experiment. All sites were located in an area that had been

closed to fishing for 6 yr. The otter trawl that was used

was a commercial shrimp trawl with a 14-m ground rope

with 20 kg of lead distributed along it, and 125-kg otter

boards. Eighty hauls were made at each treatment site

during a 1-yr period starting in December 1996, at a

frequency of two hauls per week. It was estimated that

any given area was passed over 24 times by the trawl

during the experiment.

For 61% of the species sampled, abundances tended

to be negatively affected by trawling (i.e., abundances

decreased more or increased less in the trawled sites

compared to the control sites during the experiment). Total

biomass decreased significantly at all three trawled sites,

and the total number of individuals decreased significantly

at two trawled sites, but in both cases significant

reductions were also observed at one of the control sites;

thus, these changes could not be attributed solely to

trawling. Total abundance and biomass at trawled sites

was reduced by 25% and 60%, respectively, compared to

6% and 32% in control sites. Individual phyla responded

differently to trawling. Echinoderm (mostly brittle

star)abundance decreased significantly, polychaete abundance was not affected although some families increased

and some families decreased, and amphipod and mollusk

abundances were not affected.
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7. Mayer et al. (1991) examined the immediate effects

of a single tow with an otter trawl on mud substrate at a

depth of 20 m in a bay on the coast of Maine. The trawl had

an 18-m footrope with an attached tickler chain and 90-kg

doors. Sediment core samples (to a sediment depth of 18

cm) were taken inside and outside the drag line the day after

trawling, and were analyzed for porosity, chlorophyll,

pheophytin, total organic matter, protein, extracellular

proteolytic activity, and beryllium-7.

Downcore profiles were similar between the dragged

and control sites, indicating that trawling did not “plow”

the bottom and bury surficial sediments. The trawl doors

did produce furrows several centimeters deep, and the

chain and net caused a very thin, and inconsistent, planing

of surficial features. A high value of beryllium-7 in surficial

sediments at the control site, but not at the trawled site,

indicated that fine sediments were dispersed laterally, away

from the area of dragging.

8. Pilskaln et al. (1998) collected large infaunal

worms in sediment traps deployed 25-35 m above the

bottom in two deep (250-m) basins in the GOM during 1995.

Many more worms were collected in Wilkinson Basin,

which is located in a more heavily trawled area in the Gulf,

than in Jordan Basin, which is located in a region of the Gulf

with very little trawling activity. Higher abundance

coincided with seasons of greater trawling activity in the

southwestern GOM.

The authors concluded that the worms are dislodged

and suspended in the near-bottom water column by

trawling because there was no other reason why they

would leave their natural habitat in the bottom. They also

noted that the resuspension of fine sediment by bottom

trawls releases nutrients such as nitrogen and silica from

bottom sediments.

9. Sanchez et al. (2000) examined the effects of otter

trawling in a commercially trawled area with muddy

substrate (depth 30-40 m) in the northwest Mediterranean

Sea off the coast of Spain. A commercial otter trawl was

towed repeatedly during daylight for 1 day (3.5 hr of

towing) at one site and during a 23-hr period (7 hr of

towing) at a second site in July 1997, so that each trawl

wayline was swept entirely either once or twice. Infaunal

grab samples were collected prior to fishing and at various

times after fishing (up to a maximum of 150 hr) in each trawl

wayline and at unfished sampling locations adjacent to

each wayline.

A number of taxa (mostly families) were significantly

more abundant in the lightly trawled wayline than in the

adjacent untrawled area after 150 hr, primarily due to

decreased abundance outside the wayline. The total

numbers of individuals and taxa were also significantly

reduced outside, but not inside, the lightly trawled wayline

150 hr after trawling. There were no differences in the

number of taxa or individuals inside and outside the more

intensively trawled wayline after 72 hr.

The percentage composition of abundance of major

taxa (i.e., polychaetes, crustaceans, and mollusks) was

similar in both trawled waylines and in the control locations

throughout the experiment, and trawling produced no

changes in community structure in either wayline.

Sidescan sonar images of the trawl waylines showed

furrows left by the trawl doors that remained visible

throughout the experiment.

10. Sparks-McConkey and Watling (2001) investigated the effects of trawling on geochemical sediment

properties and benthic infauna in Penobscot Bay, Maine.

The study site was selected because it was deep (60 m) and

bottom sediments were not exposed to storm events or tidal

scouring. Sediment particle size was homogeneous

spatially and temporally within the study area. There had

been no commercial trawling in the area for 20 yr. Trawling

was conducted at two stations in December 1997 with a 12-

m commercial silver hake net that was modified (increased

mesh size and decreased diameter of float rollers) to reduce

effects to the seafloor. Four tows were made at each

station during 1 day. An attempt was made to tow the

same area of bottom each time. Sampling was conducted

at the experimental stations and at seven reference

stations for a year before trawling, and 5 days, 3.5 mo,

and 5 mo after trawling. An underwater video camera

was used to verify that post-trawl grab samples were

taken in trawl tracks.

Trawling caused immediate and significant reduction

in porosity, an increase in the food value of surface

sediments (upper 2 cm), and stimulated chlorophyll

production, but none of these properties were any different

at the trawled stations after 3.5 and 5 mo. Trawling also had

immediate and significant effects on benthic infauna,

reducing the number of individuals and species, reducing

taxonomic diversity, and increasing species dominance.

There were no longer any significant differences in any of

these parameters after 3.5 mo when mobile species

recruited to the benthos. Four polychaete species were

significantly less abundant at the trawled stations 5 days

after trawling, but three of them were present in equal

densities at treatment and control stations 3.5 mo later.

Two species of bivalve mollusks were reduced in

abundance by trawling, one of them for 3.5 mo. Nemerteans

were significantly more abundant at the trawled stations

during all three post-trawl sampling dates.

11. Tuck et al. (1998) conducted experimental

trawling in a sea loch in Scotland that had been closed to

fishing for over 25 yr. Trawling was conducted 1 day/mo

(for 7.5 hr) for 16 mo in a single treatment site (95% silt-clay,

depth 30-35 m) starting in January 1994. Infaunal surveys

were completed in the trawled site and a nearby reference

site prior to, after 5, 10, and 16 mo of disturbance, and, once

trawling ended, after 6, 12, and 18 mo of recovery.

Trawl doors produced furrows in the sediment, which

were still evident in sidescan sonar images after 18 mo.
Page 84

Trawling had no effect on sediment characteristics, but

bottom “roughness” in the trawled area increased during

the disturbance period and declined during the recovery

period.

There were no significant differences in the number of

infaunal species in the experimental and reference sites

prior to the beginning of the experiment or during the first

10 mo of disturbance, but there were more species in the

trawled site after 16 mo of disturbance and throughout the

recovery period. In contrast, there were significantly more

individuals in the trawled site before trawling began. This

difference was maintained after 10 and 16 mo of fishing, and

after 6 and 12 mo of recovery, but after 18 mo, there was no

difference between the two sites. Taxonomic diversity and

evenness indices were significantly lower in the experimental site for the first 22 mo of the experiment, but after 12 mo

of recovery there were no longer any differences. Some

species (primarily opportunistic polychaetes) increased

significantly in abundance in the trawled plot in response

to the disturbance, while others (e.g., bivalve mollusks)

declined significantly in abundance relative to the

reference area. Biomass was significantly higher in the

control site before trawling started, but not during the rest

of the experiment. Two different measures of community

structure were applied. One of them indicated that the two

sites became significantly different after only 5 mo of

disturbance and remained so throughout the experiment.

According to the other one, the treatment site reached a

similar condition to the reference site at the end of the

recovery period. Trawling effects on epifauna could not be

evaluated in this study because organisms were present in

very low densities and because the trawl was not equipped

with a net, thus any effects on epifauna would have been

underestimated.

Summary

Results of 11 studies are summarized. All of the

studies were conducted during 1991-2001, five in North

America, five in Europe, and one in Australia. One study

was performed in an intertidal habitat, one in very

deepwater (250 m), and the rest in a depth range of 14-90 m.

Eight of them were experimental studies and three were

observational. Two studies examined only physical

effects, six assessed only biological effects, and three

examined both physical and biological effects. One study

evaluated geochemical sediment effects.

In this habitat type, biological evaluations focused on

infauna: all nine biological assessments examined infaunal

organisms, and four of them included epifauna. Habitat

recovery was monitored on five occasions. Two studies

evaluated the long-term effects of commercial trawling, one

by comparing benthic samples from a fishing ground with

samples collected near a shipwreck, while another

evaluated changes in macrofaunal abundance during

periods of low, moderate, and high fishing effort during a

27-yr period. Four of the experimental studies were done in

closed or previously untrawled areas and three in

commercially fished areas. One study examined the effects

of a single tow, and six involved multiple tows. Five studies

restricted trawling to a single event (e.g., 1 day) and two

examined the cumulative effects of continuous disturbance.

Physical Effects

Trawl doors produce furrows up to 10-cm deep and

berms 10-20 cm high on mud bottom. Evidence from three

studies (2, 3, 9) indicates that there is a large variation in the

duration of these features (2-18 mo). There is also evidence

that repeated tows increase bottom roughness (11), fine

surface sediments are resuspended and dispersed (7), and

rollers compress sediment (2). A single pass of a trawl did

not cause sediments to be turned over (7), but single and

multiple tows smoothed surface features (4, 7).

Biological Effects -- Single-Disturbance

Experimental Studies

Three single-event studies (1, 2, 9) were conducted in

commercially trawled areas. Experimental trawling in

intertidal mud habitat disrupted diatom mats and reduced

the abundance of nematodes in trawl door furrows, but

recovery was complete after 1-3 mo (2). There were no

effects on infaunal polychaetes (2). In a subtidal mud

habitat (30-40 m deep), the benthic infauna was not affected

(9). There were no obvious effects on macrofauna at a

deeper (75 m) site, but there were fewer organisms and

species there than at an unexploited site near a shipwreck

(1).

In two assessments performed in areas that had not

been affected by mobile bottom gear for many years (4, 10),

effects were more severe. Total infaunal abundance (4, 10)

and the abundance of individual polychaete (4, 10) and

bivalve mollusk (10) species declined immediately after

trawling.

In one of these studies (10), there were also immediate

and significant reductions in the number of species and

species diversity. Other effects included reduced porosity,

increased food value, and increased chlorophyll production in surface sediments. Most of these effects lasted <3.5

mo.

In the other study (4), two tows removed 28% of the

epifauna on mud and sand substrate (not differentiated),

and epifauna in all trawled quadrats showed signs of

damage. These results were not reported separately for

mud bottom.
Page 85

Biological Effects -- Repeated-Disturbance

Experimental Studies

Two studies of the effects of repeated trawling were

conducted in areas that had been closed to fishing for 6 yr

(6) and >25 yr (11). In one study (6), multiple tows were

made weekly for a year, and in the other (11), monthly for 16

mo.

In one case (6), 61% of the infaunal species sampled

tended to be negatively affected, but significant reductions

were only noted for brittle stars.

In the other case (11), repeated trawling had no

significant effect on the numbers of infaunal individuals or

biomass. In this study, the number of infaunal species

increased by the end of the disturbance period. Some

species (e.g., polychaetes) increased in abundance, while

others (e.g., bivalve mollusks) decreased. Community

structure was altered after 5 mo of trawling, and (because of

mixed results from the analyses) if it did fully recover, then

it did not do so until at least 18 mo after trawling ended.

Biological Effects -- Observational Studies

An analysis of benthic sample data collected from a

fishing ground over a 27-yr period of high, medium, and low

levels of fishing effort showed an increased abundance of

organisms belonging to taxa that were expected to increase

at higher disturbance levels, whereas those that were

expected to decrease did not change in abundance (5).

Trawling in deepwater apparently dislodged infaunal

polychaetes, causing them to be suspended in near-bottom

water (8).

Otter Trawls -- Sand (Table 5.5)

1. Ball et al. (2000) sampled benthic macrofauna at a

lightly fished inshore prawn trawl fishing ground in the

Irish Sea before and 24 hr after trawling and at an unfished

(for about 50 yr) “pseudo-control” site near a shipwreck.

Sediments at these two sites were muddy sand, and the

depth was 35 m. No information on the duration of

experimental trawling or the type of net used was provided.

There were no obvious short-term effects of

experimental trawling. Chronic effects, as indicated by

differences between the fished site and the wreck site

before experimental trawling began, were similar in kind, but

less pronounced than at the heavily fished, mud-bottom

offshore site (see “Otter Trawls -- Mud, 1. Ball et al.

(2000)”). Mean numbers of species and total numbers of

individuals for both infaunal and epifaunal species were

higher at the unfished wreck site, as were indices of species

diversity and richness. High intersample variance in

biomass estimates near the wreck impeded comparisons

with the trawled site. Fifty-eight species found at the

inshore wreck site were not found at the experimental

fishing site. These species included predatory and tubedwelling polychaetes as well as a number of bivalve

mollusks and echinoderms. Other types of polychaetes

were more common at the fished site.

2. Bergman and Santbrink (2000) calculated

mortality rates for a number of sedentary and relatively

immobile megafauna (i.e., >1 cm in maximum dimension)

caught or damaged by a flatfish otter trawl at six

commercially exploited sites in the southern North Sea

during 1992-1995. The substrate at two deeper sites (40-50

m) was silty sand (3-10% silt), and at four shallower sites

(<30-40 m) was sand (1-5% silt). At each site, benthic

invertebrates were sampled before and 24-48 hr after

trawling in four corridors with a dredge that was designed

to sample relatively large, relatively low-abundance ,

infaunal and epifaunal species. The fishing gear was a

commercial flatfish trawl that measured 35-55 m between

the doors (15-20 m between the wings) when underway,

with 20 m of net (32 m with bridles) in contact with the

seafloor, 20-cm roller gear, and 8-10 cm mesh in the codend. Three corridors were trawled in silty sand substrate

and one in sandy substrate. The surface of each corridor

was trawled on average 1.5 times.

Mortalities were calculated as the percent reduction

from initial density after a single trawl tow, and ranged from

<0.5 to 52% for nine species of bivalve mollusks, from 16 to

26% for a sea urchin, from 3 to 30% for a crustacean, and

from 2 to 33% for other species. Overall, mortality rates for

six species ranged from 20 to 50%, and for 10 other species

were < 20%. Significant before-and-after differences were

detected on only 11 of 54 occasions. Some species

experienced higher mortalities in the silty sand substrate

and some in the sandy substrate.

3. DeAlteris et al. (1999) used divers to determine

that simulated (i.e., dug by the divers) trawl door tracks

only lasted 1-4 days at a 7-m deep sandy site in

Narragansett Bay, Rhode Island. Natural erosion at this

site was predicted to occur on a daily basis, much more

rapidly than in deeper water with a mud substrate (see

“Otter Trawls -- Mud, DeAlteris et al. (1999)” for a summary

of the mud-bottom results).

4. Drabsch et al. (2001), in addition to sampling a

mud-bottom site in South Australia before and after

trawling (see “Otter Trawls -- Mud, Drabsch et al. (2001)”),

also sampled two additional sites (20-m depth) with

medium-coarse sand sediments and shell fragments.

Trawling effects were evaluated at one of the sites 1 wk

after fishing, and at the second site 3 mo after fishing.

Trawl doors left tracks in the sediment, and the footline

and net smoothed topographic features and removed

epifauna. In contrast to results obtained at the mud-bottom

site, trawling at the sand-bottom sites did not significantly

affect infaunal abundance. The only significant change to

infauna that could be attributed to trawling was a reduction
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in density of one order of crustaceans (Tanaidaceae) 1 wk

after trawling. Three months after trawling, infaunal

abundance had declined dramatically in both the treatment

and reference sites, and there were no significant

differences between them.

5. Frid et al. (1999) examined the long-term effects of

fishing with prawn otter trawls in the North Sea by

comparing changes on macrobenthic communities at an LF

sand-bottom site and an HF mud-bottom site during three

time periods when fishing effort was either low, moderate,

or high (see “Otter Trawls -- Mud, Frid et al. (1999)” for

results at the HF site). The LF site was located in 55 m of

water and had a predominantly sand substrate (20% siltclay). Benthic taxa collected at the LF site were divided into

two groups that were predicted to respond either

negatively (decreased abundance) or positively (increased

abundance) to increased trawling activity, based on

published accounts.

Fluctuations in macrofaunal abundance at the LF site

were correlated with the abundance of phytoplankton 2 yr

previously, indicating that benthic organisms were more

abundant when greater amounts of organic matter were

available to stimulate benthic production and vice-versa.

There was no correlation with changes in fishing effort and

no change in the proportions of organisms in the positive

and negative response groups over time.

6. Gibbs et al. (1980) sampled benthic epifauna and

infauna prior to and immediately after 1 wk of repeated

experimental trawling (with a 10-m otter trawl with 1-m x 0.5-

m flat otter boards and chain spiders) in a shallow estuary

in New South Wales, Australia, during October 1975. The

experimental trawling was conducted before the opening of

a 6-mo-long prawn fishing season. Additional samples

were collected at the end of the season. Grab samples were

taken over muddy sand (0-30 % mud-clay) at three sites

within the fishing grounds in Botany Bay and at an

unfished control site in Jervis Bay, located about 200 km

south of Botany Bay.

Trawl footropes lightly skimmed the bottom and

disturbed very little sand. Trawling did create a plume of

sand, but after repeated trawls, the seafloor was only

slightly modified. Community diversity indices were not

significantly different among the three study sites and the

control site before and immediately after experimental

trawling or after the fishing season. The authors therefore

concluded that there were no detectable effects of trawling.

7. Gilkinson et al. (1998) studied the effects of trawl

door scouring on several species of infaunal bivalve

mollusks by observing an otter door model deployed in a

test tank with a sand bottom, designed to simulate the

sediment of the northeastern Grand Banks.

The trawl door created a berm in the sediment (average

height 5.5 cm) with an adjacent 2-cm-deep scour furrow. All

42 bivalve mollusks within the scour path were displaced,

but only two were damaged.

8. Hall et al. (1993) sampled benthic infauna from a

fishing ground in the North Sea using distance from a

shipwreck as a proxy for changes in trawling intensity. The

sediment was coarse sand and the depth was 80 m. The

benthic infauna was sampled at intervals along three

transects that started 5 m from the wreck and extended to

350 m from the wreck.

Infaunal community structure was closely related to

grain size and organic carbon content that varied within

concentric rings or linear waves of coarser and finer sand,

but not to distance from the wreck. The authors concluded

that the observed differences in infaunal abundance did

not appear to be consistent with an effect of fishing

disturbance, which would most likely not follow the same

pattern of fluctuating high and low intensity at increasing

distance from the wreck. Epifaunal taxa were not included

in this analysis.

9. McConnaughey et al. (2000) examined chronic

trawling effects on epifauna in a high-energy sandy habitat

in the eastern Bering Sea, Alaska. Samples were collected

in 1996 just inside and outside an area that had been closed

to trawling since 1959, using an otter trawl modified to

improve the catch and retention of large epibenthic

organisms. The small-mesh net had a 34-m footrope with a

tickler chain and a hula skirt, and 1-mt steel V-doors with 55-

m paired dandylines (bridles). Each lower dandyline had a

0.6-m chain extension connected to the lower wing of the

net to improve bottom-tending characteristics. Sampling

sites were selected along the outside edge of the closed

area where commercial trawling is intense, and inside the

closed area within 1 nmi of the intensely trawled sites. The

bottom in the study area was 44-52 m deep, had sand

ripples and strong rotary tidal currents, and was well within

the depth range affected by storm waves.

Sedentary taxa (e.g., anemones, whelk eggs, soft

corals, stalked tunicates, bryozoans, and sponges) were

more abundant in the unfished (UF) area than in the heavily

fished (HF) area. Differences (i.e., UF>HF) were significant

for sponges and anemones. Mixed nonsignificant

responses were observed within motile groups (e.g., crabs,

starfish, and buccinid whelks) and infaunal bivalve

mollusks. Species diversity of sedentary epifaunal taxa

was significantly higher in the UF area, owing to the greater

dominance of a starfish in the HF area. Attached epifauna

(e.g., sponges, anemones, soft corals, and stalked

tunicates) had a significantly more patchy distribution in

the HF area.

10. Moran and Stephenson (2000) conducted an

experimental study of otter trawling effects on an

unexploited area with dense macrobenthos at depths of 50-

55 m on the continental shelf of northwest Australia. No
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information on bottom type was provided, but it was

presumed to be sand (see Sainsbury et al. 1997). A video

camera mounted on a sled was used to survey attached

epifauna (>20 cm in maximum length) before and after

individual trawling events in experimental and control sites.

There were four trawling events scheduled at 2-day

intervals. During each trawling event, four tows were

required to cover the area of each of two experimental

blocks so that any unit area of bottom was trawled once.

Trawled and control sites were surveyed before and after

each trawling event and on alternate days during trawling.

Mean density of benthos declined exponentially (and

significantly) with increasing tow numbers, with four tows

reducing density by about 50%, and a single tow reducing

density by about 15%. This estimated removal rate is much

lower than what was estimated by Sainsbury et al. (1997)

for sponges in the same general location (89%, see below).

The authors believe this disparity may be explained by the

fact that the trawl used in their study was lighter, with 20-

cm disks separated by 30-60 cm long spacers of 9-cm

diameter, and may have lifted over some benthic organisms

rather than removing them. In addition, sponges are more

susceptible to removal than other benthic organisms.

11. Sainsbury et al. (1997) reported the results of

surveys on the continental shelf (<200 m) in northwestern

Australia that documented a shift in the dominance of fish

species from those (Lethrinus and Lutjanus) that occur

predominantly within habitats that contain large epibenthic

organisms to those (Nemipterus and Saurida) that favor

open sandy habitats, in conjunction with the development

of a commercial stern and pair trawling fishery. Five years

after trawl closure areas were implemented (in response to

these shifts in species dominance), there were increased

catch rates of Lutjanus and Lethrinus, increased

abundances of small benthos (<25 cm), and no changes in

abundances of large benthos. The abundance of these

fishes and of both the large and small benthos continued to

decrease in the area left open to trawling.

These results increased the probability placed on a

habitat limitation model and decreased the probability of an

intraspecific control model (Sainsbury 1991), indicating

that changes in species abundance and composition were

at least in part a result of the damage inflicted on the

epibenthic habitat by demersal trawling gear. Video

observations provided by a camera mounted on a trawl

showed that during those encounters with the groundline

where the outcome was observable, sponges >15 cm were

removed from the substrate 89% of the time. The

groundline consisted of a 15-cm-diameter rubber roller

made from rubber disks packed together and threaded on

the groundline, with 14-cm spacers between packs of disks.

Grand Banks, Newfoundland: A number of

investigators (see next three summaries) have examined the

physical and biological effects of sustained otter trawling

in a relatively deep sand habitat (120-146 m) in a 100-nmi2

area of the Grand Banks, Newfoundland, that was closed to

commercial trawling in 1992. Analysis of fishing effort

records indicated that it had not been fished intensively

since the early 1980s (Kulka 1991). (A 1990 estimate of the

intensity of seafloor disturbance by otter trawling in the

study area was <8% per year per unit of bottom area, or one

set every 12 yr).

Sediments at this site were moderately to well sorted,

fine to medium-grained sand. The seafloor is smooth and

relatively stable with no evidence of wave- induced ripples.

However, interannual variations in grain size and acoustic

properties were observed during the study, possibly

caused by winter storms (Schwinghamer et al. 1998).

Twelve experimental trawl tows (31-34 hr of total

trawling) were made in three 13-km long corridors with an

Engel 145 otter trawl with 1250-kg oval otter boards and 46-

cm diameter rock hopper gear during a 5-day period in late

June - early July of 1993, 1994, and 1995. Since the width of

the trawl opening (60 m) was considerably less than the

width of the disturbance zones created (120-250 m), the

average experimental trawling intensity was estimated to be

3-6 sets per year per unit of bottom area.

Physical and biological effects of trawling were

evaluated in two of the three experimental corridors. The

corridors were sampled just before and just after (within a

few hours or days) the experimental trawling ended, as well

as 1 yr later. Additionally two reference corridors -- each

located parallel to an experimental corridor -- were sampled

just before the experimental trawling. Samples were also

collected in the reference and experimental corridors in

September 1993, 2 mo after trawling.

12. Kenchington et al. (2001) analyzed the effects of

otter trawling at the Newfoundland study site on benthic

infauna and epifauna collected in grab samples in two of

the three experimental corridors.

The most prominent feature of the sample data was a

significant natural decline in the total number of individuals

(or total abundance), the number of species, and the

numbers and biomass of several selected species in both

the trawled and untrawled corridors between July 1993 and

July 1995. The total abundance declined by 50% during the

2-yr period.

There were also significant effects of trawling on the

mean total abundance per sample of all taxa and on the

individual abundances of 15 taxa (mostly polychaetes), but

only in 1994. In that year, immediate declines in abundance

for these 15 taxa ranged from 33 to 67%. There were no

significant trawling-induced changes in total biomass at

any point during the experiment. Likewise, none of the

community indices (taxonomic diversity and evenness)

showed a significant effect of trawling in any of the years,

and the only change in community structure that could be

attributed to trawling occurred in 1994. Recovery for

species that were affected by trawling in 1994 required <1

yr. Within this time frame, however, the actual recovery

period could not be determined.
Page 88

The authors concluded that there was no consistent,

long-term effect that could be attributed to trawling, and

that the effects of otter trawling on benthic infauna and

infauna in this relatively stable, deepwater sand habitat

were limited and short-term. When trawling disturbance

was indicated, it appeared to mimic natural disturbance.

13. Prena et al. (1999) examined trawl bycatch and

the effects of trawling on benthic epifauna, using an Engel

145 otter trawl. The epifauna (and some infauna) were

collected with an epibenthic sled in two reference corridors

before trawling, and in two experimental corridors before

and after trawling (see earlier).

There was a significant reduction in trawl bycatch

biomass during the first six sets (15-17 hr) due primarily to a

decline in snow crabs, and a relatively constant level of

such biomass during the last six sets due to snow crabs

migrating into the trawled corridors to feed on dead and

damaged organisms.

Epifaunal biomass was lower (by 24%on average) in

trawled corridors than in reference corridors in all 3 yr, and

remained relatively constant with time, whereas biomass in

reference corridors was highly variable from year to year.

There were significant trawling and year effects on total

epifaunal biomass, and significant trawling effects on mean

individual epifaunal biomass, indicating that individuals in

the trawled corridors had a smaller average size.

At the species level, the biomass of five of the nine

dominant epifaunal species (a sand dollar, brittle star, soft

coral, snow crab, and sea urchin) was significantly lower in

the trawled corridors than in the reference corridors. There

was also a general trend of greater damage to benthic

invertebrates in the trawled corridors, especially for three

species of brittle star, sea urchin, and sand dollar. There

were no significant effects on the abundance of four

dominant mollusk species.

14. Schwinghamer et al. (1998) sampled surface

sediments (top 2 cm) and conducted video and acoustic

surveys at the Newfoundland study site before, during,

and after trawling in two experimental corridors. Tracks and

berms left by the trawl doors increased bottom relief and

roughness. In 1993, door tracks 5 cm deep and 1 m wide

were still clearly visible in sidescan sonar records after 2

mo, but they were not visible at the beginning of trawling in

1994. Tracks made in 1994 were faintly visible at the

beginning of trawling in 1995.

On a small scale, trawling suspended and dispersed

sediment, flattened the seafloor, and removed biogenic

mounds and organic matter deposited in depressions.

Seafloor topography recovered within 1 yr. Sediment grain

size varied significantly between corridors and among years,

but there was no evidence that it was affected by trawling.

Large, epibenthic organisms (e.g., basket stars, snow

crabs, and brittle stars) were readily visible in experimental

and reference corridors, but tended to be arranged in linear

features parallel to the axis of trawling in the experimental

corridors.

The authors concluded that even at a depth of 120-146

m, natural disturbances such as bioturbation and storms

might cause more pronounced physical changes to the

bottom than those caused by trawling.

Summary

Results of 14 studies are summarized. One of them was

described in a 1980 publication; the rest have been

published since 1993. Six studies were conducted in North

America (three in a single long-term experiment on the

Grand Banks), four in Australia, and four in Europe. Ten

were experimental studies. Eight of them were done in

depths <60 m, one at 80 m, and four in depths >100 m. One

study examined just the physical effects of trawling, nine

examined just the biological effects, and four examined

both. Six of the biological studies were restricted to

epifauna, two were restricted to infauna, and five included

both epifauna and infauna.

The only experiment that was designed to monitor

recovery was the one on the Grand Banks, although

surveys conducted in Australia documented changes in

the abundance of benthic organisms in an area after 5 yr of

fishery closures, and in an area after 15 yr of little or no

fishing activity. Two studies compared benthic communities in trawled areas of sandy substrate with those in

undisturbed areas near a shipwreck. Six studies were

performed in commercially exploited areas, five were

performed in closed areas, and two compared closed and

open areas; one was done in a test tank.

All the experimental studies examined the effects of

multiple tows (up to six per unit area of bottom), and the

study in Australia assessed the effects of 1-4 tows on

emergent epifauna. Trawling in four studies was limited to

a single event (i.e., 1 day to 1 wk), whereas the Grand Banks

experiment was designed to evaluate the immediate and

cumulative effects of annual 5-day trawling events in a

closed area over a 3-yr period.

Physical Effects

A test tank experiment showed that trawl doors

produce furrows in sandy bottom that are 2 cm deep, with a

berm 5.5 cm high (7). In sandy substrate, trawls smoothed

seafloor topographic features (4, 14), and resuspended and

dispersed finer surface sediment, but had no lasting effects

on sediment composition (14).

Trawl door tracks lasted up to 1 yr in deep water (14),

but only for a few days in shallow water (3). Seafloor

topography in deep water recovered within a year (14).
Page 89

Biological Effects -- Single-Disturbance

Experimental Studies

Three single-event studies (1, 2, 6) were conducted in

commercially trawled areas. In one of these studies (2),

otter trawling caused high mortalities of large (>1 cm)

sedentary and/or immobile epifaunal species. In another

study (6), there were no effects on benthic community

diversity. Neither of these studies investigated effects on

total abundance or biomass. In the third study (1), there

were no obvious effects on macrofauna, but there were

fewer organisms and species there than at an unexploited

site near a shipwreck.

Two studies (4, 10) were performed in unexploited

areas. In one study (10), single tows reduced the density of

attached epifauna (>20 cm) by 15%, and four tows reduced

it by 50%. In the other study (4), two tows removed 28% of

the epifauna on mud and sand substrate, and the epifauna

in all trawled quadrats showed signs of damage. (These

results were not reported separately for sand bottom.) In

this latter study, total infaunal abundance was not affected,

but the abundance of one family of polychaetes was

reduced.

Biological Effects -- Repeated-Disturbance

Experimental Studies

Intensive experimental trawling on the Grand Banks

reduced the total biomass of epibenthic organisms and the

biomass and average size of a number of epibenthic species

(13). Significant reductions in total infaunal abundance

and in the abundance of 15 selected taxa (mostly

polychaetes) were detected during only 1 of 3 yr, and there

were no effects on biomass or taxonomic diversity (12).

Biological Effects -- Observational Studies

Changes in benthic macrofaunal abundance in a lightly

trawled location in the North Sea were not correlated with

historical changes in fishing effort (5). Changes in infaunal

community structure at increasing distances from a

shipwreck in the North Sea were related to changes in

sediment grain size and organic carbon content (8).

The Alaska study (9) showed that the epifauna

attached to sand was more abundant inside a closed area,

significantly so for sponges and anemones. A single tow

in a closed area in Australia removed 89% of the large

sponges in the trawl path (11).

Otter Trawls -- Gravel/Rocky Substrate (Table 5.6)

1. Auster et al. (1996) observed bottom conditions

during a July 1987 submersible dive at a depth of 94 m near

the northern end of Jeffreys Bank, in a gravel area where

there were large (>2-m diameter) boulders. A thin layer of

mud covered the gravel and boulders, and the rock

surfaces supported large numbers of erect sponges, sea

spiders, bryozoans, hydroids, anemones, crinoid sea

feathers, and ascidians. Smaller mobile fauna, including

several species of crustaceans, snails, and scallops, was

also abundant.

When the area was resurveyed in August 1993, much

of the mud veneer was gone and there was evidence that

boulders had been moved. Abundance of erect sponges

was greatly reduced, and most of the associated epifaunal

species were not present. The authors attributed this

disturbance to otter trawling which was occurring in the

area during the second survey, and which was conducted

in this area only after 1987, when modifications to fishing

gear allowed fishermen to trawl rocky, boulder habitat in

the GOM.

2. Freese et al. (1999) documented the effects of

single tows with a bottom trawl in an area that had been

exposed to very little or no commercial trawling since the

1970s in the eastern Gulf of Alaska. The trawl was a 42.5-m

“Nor’easter” otter trawl with 0.6-m diameter rubber tire

groundgear attached to the footrope, and with 0.45-m

diameter rockhopper disks and steel bobbins along the

wings. Eight tows were made on predominantly pebble

substrate (some cobble and boulders were also present) at

depths of 206-274 m in August 1996. Quantitative video

transects, using a two-man submersible, were made down

the center of each trawl path within 2-5 hr after each tow,

and in adjacent reference areas.

The trawl moved 19% of the boulders (median size of

0.75 m) it encountered. On less compact substrate, tire gear

left a series of furrows that were 1-8 cm deep. On compact

substrate (i.e., with a greater percentage of cobble), the tire

gear left no furrows, but the trawl removed an overlying

layer of silt.

Single tows caused significant decreases in the

density of undamaged vase sponges, morel sponges, sea

whips, and anemones. Nonsignificant reductions in the

density of undamaged organisms were also observed for

finger sponges, brittle stars, sea urchins, and one species

of sea cucumber. None of the five groups of motile

invertebrates showed a significant reduction in density

because of trawling. In fact, arthropods and mollusks were

more abundant in the trawled areas.

Trawling also caused considerable damage to sponges

and sea whips. More than 50% of the vase sponges and

sea whips in the trawl transects were either damaged or

removed from the substrate. Morel sponges were also

damaged, but damage could not be quantified because this

species is much more brittle and friable than the vase

sponges, and specimens crushed by the trawl were

completely torn apart and scattered. Some finger sponges

were also knocked over onto the substrate. Brittle stars
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were also damaged, but reticulate anemones and motile

invertebrates were not.

Observations of fishes made during this study showed

that rockfish (Sebastes spp.) use cobble-boulder and

epifaunal invertebrates for cover.

3. Dolah et al. (1987) assessed the effects of a single

trawl tow on attached sponges and corals in an unexploited

area on the coast of Georgia, in the southeastern United

States. The bottom (depth 20 m) was smooth rock with a

thin layer of sand and an extensive sessile invertebrate

growth. The trawl was a 40/54 fly net with a 12.2-m

headrope and a 16.5-m footrope equipped with six 30-cm

rubber rollers separated by numerous 15-cm diameter

rubber disks, and was attached to 1.8x1.2-m China-V doors

using 30.5-m leglines.

Densities of three of the most abundant large sponges,

three dominant soft corals, and one hard coral were

determined by divers before trawling, immediately after

trawling, and 12 mo after trawling, both inside and outside

the trawl path. Sponges and soft corals <10 cm high were

not counted, but all hard corals were counted. In addition,

the degree of damage was evaluated.

The trawl damaged some specimens of all species,

sponges more notably than corals. Immediately after

trawling, undamaged sponges were less abundant,

significantly so in two transects that had higher pre-trawl

sponge densities. Damage was noted for 31.7% of the

sponges that remained in the trawled transects immediately

after trawling. Most of the reduction in, and damage to,

sponges was for the most abundant species, a barrel

sponge. For the other large sponges -- vase sponges and

finger sponges -- there were no significant differences in

density between sampling periods, although there was

some evidence of trawl damage. Twelve months after

trawling, sponges in the trawled quadrats were at pre-trawl

densities or higher, and all damaged sponges had

regenerated new tissue.

Total abundance of soft corals declined in the trawl

alley immediately after trawling, and a few damaged

specimens were found, but effects were minimal compared

to the sponges. There were no differences between pretrawl and post-trawl density estimates for fan and whip

corals. The more abundant stick coral was less abundant

immediately after trawling, but had recovered completely 12

mo later.

Divers counted 30% fewer undamaged stony corals in

the trawled quadrats immediately after trawling, although

the reduction was not significant. Of the seven colonies of

stony coral affected by the trawl, four were moderately to

heavily damaged, and three were only slightly damaged.

Twelve months later, stony corals were more abundant

than they were before trawling, and no damage could be

detected.

Summary

Three studies of otter trawl effects on gravel and rocky

substrate are summarized in this document. All three were

conducted in North America. Two were done in glacially

affected areas in depths of about 100-300 m using

submersibles, and the third was done in a shallow coastal

area in the southeastern United States.

One study involved observations made in a gravel/

boulder habitat 6 yr apart (i.e., before and after trawling

affected the bottom). The other two were experimental

studies of the effects of single trawl tows. One of these

experimental studies was done in a relatively unexploited

gravel habitat, and the other on a smooth rock substrate in

an area not affected by trawling.

Two studies examined effects to the seafloor and on

attached epifauna and one only examined effects on

epifauna. There were no assessments of effects on

infauna. Recovery was evaluated in one case for 1 yr.

Physical Effects

Trawling displaced boulders and removed mud

covering boulders and rocks (1). Rubber tire groundgear

left furrows 1-8 cm deep in less compact gravel sediment

(2).

Biological Effects

Trawling in gravel and rocky substrate reduced the

abundance of attached benthic organisms (e.g., sponges,

anemones, and soft corals) and their associated epifauna

(1, 2, 3), and damaged sponges, soft corals, and brittle stars

(2, 3). Sponges were more severely damaged by a single

pass of a trawl than soft corals, but 12 mo after trawling all

affected species, including one species of stony coral, had

fully recovered to their original abundance, and there were

no signs of damage (3).

Otter Trawls -- Mixed Substrates (Table 5.7)

1. The Canadian Department of Fisheries and Oceans

(DFO 1993) conducted a sidescan sonar survey in the Bras

D’Or Lakes system in Nova Scotia to document the

physical effects of various mobile fishing gears 1 yr after

the area was closed to mobile gear. Water depths ranged

from 10 to 500 m, and bottom sediments included rich

organic mud, clay, pebbly mud, well sorted sand, gravel,

and boulders.

Otter doors left parallel marks in the sediments, with

spoil ridges or berms faintly visible along their inner
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margins, and fainter marks between the two door marks

apparently produced by the trawl footgear. These marks

were seen predominantly in muddy sediments.

2. Engel and Kvitek (1998) compared a lightly fished

(LF) and a heavily fished (HF) area off central California

with similar sediments (gravel, sand, silt-clay) and depths

(180 m) using still photographs and videotapes taken from

a submersible in October 1994, and grab samples collected

during 1994, 1995, and 1996. There were no differences in

sediment composition between the two study sites. They

estimated that any square meter of bottom area in the HF

area was exposed to 12 times more trawling effort during

1989-1996 than any square meter of bottom area in the LF

area.

Results indicated that the HF area had significantly

more trawl tracks, shell fragments, and exposed sediment,

significantly fewer rocks and biogenic mounds, and

significantly less flocculent material. Based on the 1994

video transects, the densities of all six large invertebrate

epifauna were higher in the LF area, significantly so for sea

pens, starfish, sea anemones, and sea slugs. Based on the

grab samples, the number of polychaete species was higher

in the LF area in 1994 and 1996, and the densities of

nematodes, oligochaetes, and brittle stars were higher in

the HF area in all 3 yr (although differences, in most cases,

were insignificant). No consistent (or significant)

differences were detected for crustaceans, mollusks, or

nemerteans. One polychaete species that was the most

important prey item for three species of flounder was more

abundant in the HF area in all 3 yr, significantly so in 1994

and 1996.

The authors concluded that trawling reduces habitat

complexity and biodiversity, while increasing opportunistic infauna and prey important in the diet of some

commercially important fish species, but that, since the

study lacked controls, there was no way to be sure that the

observed differences between the two areas were, in fact,

due to differences in trawling intensity.

3. Smith et al. (1985) reported that diver observations

and videotapes showed minor surface sediment disturbance (<2.5 cm deep) within the sweep path of an otter trawl

with 6-ft (1.8-m) doors and 3/8-in (1-cm) footrope chain in

Long Island Sound. Sediments in the study area were

described as sand with mud and clay.

Much of the observed disturbance was created by

turbulence suspending small epifaunal organisms, silt, and

flocculent material as the net passed, rather than by direct

physical contact of the net with the bottom. Trawl door

tracks (<5 cm deep in sand; 5-15 cm deep in mud) were the

most notable evidence of trawl passage. These tracks were

soon obscured by the effect of tidal currents, but attracted

mobile predators. Alteration of existing lobster burrows

was minor and appeared easily repairable by resident

lobsters. The use of roller gear of unspecified size on mud

bottom left shallow scoured depressions; the use of

spacers between disks reduced such scouring.

Summary

Three studies of the effects of otter trawls on mixed

substrates are summarized. All three were conducted in

North America and relied on sidescan sonar and/or

observations made by divers or from a submersible.

One study (2) combined submersible observations and

benthic sampling to compare the physical and biological

effects of trawling in both a lightly fished and heavily

fished location in California. Both locations had the same

depth and a variety of sediment types. The other two

studies were a survey of seafloor features produced by

trawls in a variety of bottom types (1), and primarily an

examination of the physical effects of single trawl tows on

sand and mud bottom (3).

Physical Effects

Trawl doors left tracks in sediments that ranged from

<5 cm deep in sand to 15 cm deep in mud (1, 3). In mud,

fainter marks were also made between the door tracks,

presumably by the footgear (1).

A heavily trawled area had fewer rocks, shell

fragments, and biogenic mounds than a lightly trawled area

(2).

Biological Effects

The heavily trawled area in California had lower

densities of large epifaunal species (e.g., sea slugs, sea

pens, starfish, and anemones) and higher densities of

brittle stars and infaunal nematodes, oligochaetes, and one

species of polychaete (2). There were no differences in the

abundance of mollusks, crustaceans, or nemerteans

between the two areas. However, since this was not a

controlled experiment, these differences could not be

attributed to trawling.

Single trawl tows in Long Island Sound attracted

predators and suspended epibenthic organisms into the

water column (3).

New Bedford-Style Scallop Dredges

New Bedford-Style Scallop Dredges -- Sand (Table

5.8)

1. Auster et al. (1996) mapped Stellwagen Bank

(GOM) in 1993 (depth 20-55 m) using sidescan sonar, and

showed it to be covered by large expanses of sand, gravelly
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sand, shell deposits, and gravel. Waves produced by large

storms from the northeast create ripples in coarse sand

measuring 30-60 cm between crests and 10-20 cm high, and

deposit large sheets of fine sand with low sand waves 15-35

m between crests. The troughs of these sand waves are

filled with shell debris.

Gear tracks produced by trawls and scallop dredges

could be distinguished in the sonar images. Examination of

gear tracks in sonar images showed that scallop dredges

disturb sand ripples and disperse shell deposits.

2. Langton and Robinson (1990) analyzed visual and

photographic observations made during submersible

transects on an offshore bank in the GOM (Fippennies

Ledge) in July 1986 and June 1987. There was little

evidence of scallop dredging at the dive site in 1986, but it

was heavily dredged sometime between the 1986 and 1987

submersible observations (Langton and Robinson 1988).

Depth near the study transects (southeastern end of the

ledge) ranged from 80 to 100 m. In the areas of highest sea

scallop density, the surficial sediments were usually sand

with occasional shell hash and small rocks. Where there

were tubes formed by amphipods or polychaetes, the

sediment surface was visually a more silty organic sand.

Grain size analysis revealed that the upper 5 cm of sediment

was uniform throughout the area, and averaged 84% sand,

with some gravel.

Dredged areas observed in 1987 were clearly

distinguishable from undredged, or not recently dredged,

areas. The most obvious result of dredging was a change

from organic silty sand to gravelly sand. This was

apparently due to the disruption of amphipod tube mats.

Occasionally, piles of rock and scallop shells were

observed, apparently deposited there when dredges were

emptied at the surface.

Densities of three dominant megafaunal species (sea

scallops, burrowing anemones, and a tube-dwelling

polychaete) declined significantly between 1986 and 1987,

apparently because of dredging.

3. Watling et al. (2001) evaluated the geochemical

and biological effects of scallop dredging in an estuary

(Damariscotta River, Maine). The study site was located

on an unexploited side of the estuary in a shallow (15 m),

silty sand area with a low density of sea scallops. Bottom

samples for sediment chemistry, microbiology, and fauna

were collected by divers in a control and an experimental

plot before and after intensive dredging (23 tows in 1 day)

using a 2-m-wide chain-sweep dredge towed at 2 knots.

Sampling of benthic macrofauna (primarily infauna) was

conducted 4 and 5 mo before dredging, immediately before

and after (1 day) dredging, and 4 and 6 mo after dredging,

by divers with push cores.

The immediate effects of dredging were the loss of fine

material from the top few centimeters of the sediment

surface, and a reduction in its food value (significant

reductions in enzymatically hydrolysable amino acids and

total microbial biomass). There was little discernible

difference in the number of macrofauna taxa present after

dredging, but the numbers of individuals were greatly (and

significantly) reduced. Some taxa (families) showed little

difference between the control and treatment site the day

after dredging, while others were reduced in abundance.

Significant reductions were noted for one family each of

polychaetes (Nephtyidae) and amphipods (Photidae).

In the experimental plot, fine sediments still had not

been restored 6 mo after dredging, whereas the food value

of the sediments had completely recovered after 6 mo.

Total macrofaunal abundance was still significantly lower 4

mo afterwards, but after 6 mo there was no longer any

significant difference in the number of individuals in the

two plots. Some taxa recovered sooner than others.

Summary

Three studies of the effects of New Bedford-style

scallop dredges on sand substrate are summarized, and all

were performed since 1990. One was conducted in an

estuary on the Maine coast (3) and two on offshore banks

in the GOM (1, 2). Two of them were observational in

nature, but didn’t include any direct observations of

dredge effects. The other one was a controlled experiment

conducted in an unexploited area in which a single dredge

was towed repeatedly over the same area of bottom during

1 day.

One study examined physical effects and two

examined physical and biological effects. One of them

included an analysis of geochemical effects to disturbed

silty sand sediments.

Physical Effects

Dredging disturbed physical and biogenic benthic

features [sand ripples and waves (1), shell deposits (1), and

amphipod tube mats (2)], caused the loss of fine surficial

sediment (3), and reduced the food quality of the remaining

sediment (3). Sediment composition was still altered 6 mo

after dredging, but the food quality of the sediment had

recovered by then.

Biological Effects

There were significant reductions in the total

number of infaunal individuals in the estuarine location

immediately after dredging and reduced abundances of

some taxa (particularly one family each of polychaetes

and amphipods), but no change in the number of taxa (3).

Total abundance was still reduced 4 mo later, but not

after 6 mo.
Page 93

The densities of two megafaunal species (a tubedwelling polychaete and a burrowing anemone) on an

offshore bank were significantly reduced after commercial

scallop vessels had worked the area (2).

New Bedford-Style Scallop Dredges -- Mixed

Substrates (Table 5.9)

1. Caddy (1968) described diver observations of

dredge effects in shallow sea scallop beds in the

Northumberland Strait (Gulf of St. Lawrence, Canada). The

depth was about 20 m and the sediments ranged in texture

from mud to clean sand. Fishing operations were

conducted with a 2.4-m-wide, offshore chain-sweep scallop

dredge (no teeth) that was modified to reduce its weight by

replacing the forward drag bars with chains. The dredge

weighed 0.36 mt (800 lb) out of the water. Divers attached

to the dredge made direct observations during two 5-min

tows that were made at about 2 knots.

The lateral skids, located at each end of the pressure

plate produced two parallel furrows approximately 3 cm

deep; a series of smooth ridges between them were caused

by the rings in the chain belly of the dredge. Dislodged

pieces of dead shell were more evident within the drag

tracks than on the surrounding bottom.

2. Caddy (1973) used a two-man submersible to

observe the effects of a 2.4-m-wide, chain-sweep dredge

(no teeth, weight 0.6 mt or 1300 lb out of the water) and a

gang of three 0.8-m-wide, Alberton-style, toothed dredges

in a previously dredged area of Chaleur Bay in the Gulf of

St. Lawrence (Canada). (See “Toothed Scallop Dredges --

Mixed Substrates, 4. Caddy (1973)” for a summary of the

toothed-dredge results.) Observations were made inside

and outside dredge tracks within 1 hr of each tow. Depth

varied from 40 to 50 m, and the substrate was sand overlaid

by glacial gravel, 1-10 cm in diameter, with occasional

boulders up to 60 cm in diameter embedded in the gravel.

Dredging suspended fine sediments and reduced

visibility from 4-8 m to <2 m within 20-30 m of the track, but

the silt cloud dispersed within 10-15 min of the tow, coating

the gravel in the vicinity of the track with a thin layer of fine

silt. The chain-sweep dredge left a flat track that increased

in depth from just below the sediment surface to several

centimeters deep at the end (tows were 0.8-1.2 km long).

Over areas of sand and fine gravel, marks were left by

individual belly rings, and the tow bar left a narrow

depression in the center of the track. The edge of the track

was sometimes marked by an impression left by the lateral

skids.

Gravel fragments were less frequent inside the track,

and many were overturned. Rocks 20-40 cm in diameter

were dislodged every 10-30 m of track. Some boulders were

overturned and others were plowed along, leaving a

groove several meters long. Empty holes left by some of

the rocks were evident.

3. Mayer et al. (1991) investigated the effects of

scallop dredging at a shallow (8 m) nearshore site on the

Maine coast with a mixed mud, sand, and shell hash

substrate. The site was dragged with a New Bedford-style,

chain-sweep dredge (presumably once, although no

information was provided), and core samples were

collected before dredging and 1 day after dredging inside

and outside the dragged track.

Dredging lowered the substrate by 2 cm and tilled the

sediment to a depth of 9 cm, causing finer material (sand

and mud) to be injected into the lower 5-9 cm of the

sediment profile, and increasing mean sediment grain size

to >5 cm. (No statistical tests were performed with these

data). Organic matter profiles were strongly affected by

dredging. Total organic carbon and nitrogen at the new

sediment-water interface were markedly reduced in

concentration after dredging, and carbon concentrations in

the 5-9 cm sediment depth interval were considerably

higher in the dredged site.

A diatom mat on the surface of the sediment was

disrupted by the dredge and partially buried. The microbial

community of the surface sediments increased in biomass

following dredging.

Summary

Three studies have been conducted on mixed glacially

derived substrates, two of them over 20 yr ago and one 10

yr ago. All were done in the Northwest Atlantic (one in the

United States and two in Canada) at depths of 8-50 m.

Two observational studies examined physical effects

and one experimental study examined effects on sediment

composition to a sediment depth of 9 cm. The experimental

study evaluated the immediate effects of a single dredge

tow. None of these studies evaluated habitat recovery or

biological effects, although one (3) examined geochemical

effects.

Physical Effects

Direct observations in dredge tracks in the Gulf of St.

Lawrence documented a number of physical effects to the

seafloor, including bottom features produced by dredge

skids, rings in the chain bag, and the tow bar (1, 2). Gravel

fragments were moved and overturned, and shells and

rocks were dislodged or plowed along the bottom (2).

Sampling 1 day after a single dredge tow revealed that

surficial sediments were resuspended and lost, and that the

dredge tilled the bottom, burying surface sediments and

organic matter to a depth of 9 cm, increasing the mean grain
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size of sediments to >5 cm, and disrupting a surface diatom

mat (3). Microbial biomass at the sediment surface

increased because of dredging (3).

Toothed Scallop Dredges

Toothed Scallop Dredges -- Sand (Table 5.10)

Port Phillip Bay, Australia: The physical and

biological effects of toothed scallop dredges were

evaluated at three sites in a large, relatively low-energy,

predominantly tidal embayment in southeast Australia in

1991 that had been commercially dredged for Pecten

fumatus since 1963. Habitat-related objectives of these

studies were to test whether dredging alters turbidity and

sedimentation patterns in the bay, to evaluate the physical

effects of dredging on the seafloor, and to determine the

magnitude and direction of changes to the benthic

community caused by dredging. These studies were

described in four separate publications (see below).

Depths at the three sites were similar (about 15 m), but

each site had different sediments and was exposed to

different current strengths and wave characteristics.

Sediments at the three sites were: 1) fine and very fine sand

with 15% silt-clay (St. Leonards); 2) medium fine sand with

7% silt-clay (Dromana); and 3) muddy sand with shell

fragments and 30% silt-clay (Portarlington).

Three large (0.36-km2

) experimental plots (one per site)

located within larger (20-30 km2) areas which were closed to

dredging in 1991 were dredged repeatedly by a fleet of 5-7

commercial dredge vessels using 3-m-wide “Peninsula”-

style box dredges fitted with cutter bars that did not extend

below the skids. Experimental dredging intensity at

Portarlington (716 tows in 4 days during a 3-wk period) was

equivalent, on average, to four tows per unit of area, and

duplicated heavy commercial dredging intensity, based on

historical levels of fishing effort in the bay. Dredging at the

other two sites was less intensive (382 and 459 tows, and an

average of two tows per unit of area) and limited to 2- or 3-

day periods. The amount of commercial dredging activity

in the bay declined dramatically after 1987 (Currie and Parry

1996), so the study sites had been virtually undisturbed for

4 yr when the research was conducted.

Black and Parry (1994[1], 1999[2]) and Currie and

Parry (1996[3], 1999b[4]) evaluated the physical effects

of experimental dredging in Port Phillip Bay by using a

variety of field sampling techniques at all three sites.

Turbidity levels and dredge penetration depths were

measured immediately after dredging. Visually apparent

changes to the seafloor were assessed by divers with video

cameras at various times before and after dredging. The

last observations were made at St. Leonards 11 mo after

dredging, at Portarlington 7 mo after dredging, and at

Dromana 5 days after dredging.

Dredging disturbed the top 1-2 cm of sediment, but

sometimes penetrated up to 6 cm in softer sediments.

Turbidity plumes extending 1-2 m into the water column

were created immediately behind the dredge, reaching

turbidity levels within 2-16 sec after dredging which were 2-

3 times greater than the turbidity caused by storms.

Dredging-related turbidity levels returned to natural storm

levels after about 9 min at sites which were 60 and 80 m

downcurrent of the nearest boundary of the experimental

dredging plots.

Video observations showed that the sediment plume

was entrained across the full width of the dredge, mostly by

the cutterbar. As the dredge traveled across the rough

seafloor, the cutterbar trimmed off the high regions,

creating turbulent pulses of sediment. Smaller sediment

plumes were also produced by the skids.

Dredging at one of the experimental sites had a

graderlike effect on the seafloor, flattening low-relief

mounds produced by burrowing callianassid shrimp, and

filling in depressions between them. Parallel tracks up to

2.5 cm deep were produced by the dredge skids. The

mounds reformed after 6 mo. Flat areas between the

mounds were still visible after 6 mo, but 11 mo after

dredging there were no visible differences in topography

between the control plot and the dredged plot. The tracks

were still visible a month after dredging, but not after 6 mo.

At one of the other two sites (i.e., Dromana), small

parallel sand ripples in part of the dredged plot were

obliterated by dredging, but reformed immediately

following a storm that occurred 5 days after the area was

dredged. Mounds were reformed 7 mo after dredging, but

were still smaller than in the control plot.

Currie and Parry (1996[3], 1999b[4]) evaluated the

biological effects of dredging on benthic infauna in Port

Philip Bay. At the most intensively sampled site (St.

Leonards), grab samples were collected in both a dredged

plot and an adjacent control plot on three occasions before

dredging, immediately after dredging, and at 3 wk and at 3.5,

5, 8, and 14 mo after dredging. Sampling at the other two

sites was intended to evaluate very short-term biological

effects, and was limited to the dredged plots: grab samples

were taken 8 days before and 2 days after dredging at

Dromana, and 10 days before and 1 day after dredging at

Portarlington. In addition, a plankton net was attached to

the top of the dredge to sample animals thrown up by the

dredge during each tow at St. Leonards.

At the St. Leonards site, there was a significant

decrease in the number of infaunal species in the dredged

plot relative to the control plot 3 wk after dredging that

persisted for 14 mo, but there was no effect on the total

number of individuals.

In the 3.5 mo following dredging, six of the ten most

common benthic species showed significant decreases in

abundance of 28-79% on at least one-half of the

experimental plot; most species decreased in abundance by
Page 95

20-30%. At the other two sites (Portarlington and

Dromana), two and three of the ten most common species,

respectively, were significantly reduced in abundance

within 1-2 days after dredging, but reduced sampling

intensity limited the statistical power of the tests. Of the six

species whose abundance was reduced significantly over

the first 3.5 mo at the St. Leonards site, two were affected

for 3.5 mo, two for 8 mo, and two for 14 mo. Dredging

effects at this site became undetectable for most species

following their annual recruitment; most species recruited

within 6 mo, but a few still had not recruited after 14 mo.

Species that occurred on or near the sediment surface

(e.g., tube-dwelling amphipods) were released into the

water column right away, whereas species inhabiting

deeper sediments (e.g., burrowing polychaetes) were

dislodged as dredging continued. More mobile,

opportunistic species inhabiting surface sediments increased in abundance during the 3.5 mo after dredging,

perhaps because the removal of other species increased

their food supply. Dissimilarity measures between the two

plots increased after dredging, reaching a maximum 3 wk

after dredging, and suggesting that there were delayed

effects on community structure such as increased

predation of infaunal organisms that were uncovered by

dredging.

Although this research clearly demonstrates that there

were biological effects of scallop dredging to benthic habitats

in Port Phillip Bay, the reductions in density caused by

dredging were small compared to natural changes in

population densities during the year (Currie and Parry 1996).

Furthermore, changes to infauna caused by dredging in 1991

were smaller than the cumulative changes to infaunal

community structure in Port Philip Bay over the preceding 20

yr (Currie and Parry 1999b). Currie and Parry (1999a) also

concluded that changes to benthic community structure

(species composition) caused by dredging in the bay were

small compared with natural differences between study areas.

5. Butcher et al. (1981) documented diver observations of scallop dredging in Jervis Bay, New South

Wales, Australia, over large-grained firm sand shaped in

parallel ridges at depths >13 m. The dredge design was not

described, but had teeth that extended up to 5 cm below the

leading edge of the dredge.

Dredging flattened sand ridges and produced a

sediment plume extending up to 5 m into the water column

that settled out within 15 min. Dredge paths were clearly

visible, and “old” dredge paths could be seen.

6. Eleftheriou and Robertson (1992) examined the

incremental effects of repeated scallop dredge tows in

Firemore Bay, a shallow sandy bay in Loch Ewe on the west

coast of Scotland in July-August 1985. The depth at the

study site was about 5 m, and the sediment was well sorted

sand. It was a high-energy environment exposed to wave

action. Fishing (divers and beam trawls) took place in the

bay during the 1970s and 1980s.

A 1.2-m-wide, Newhaven-style scallop dredge with

nine, 12-cm-long teeth was towed 25 times over the same

track during a 7-day period (i.e., two tows on day 2, two on

day 3, eight on day 4, and thirteen on day 8). The chain bag

was removed from the dredge so that all organisms that

passed through the mouth of the dredge were returned to

the bottom for observation.

Grab samples were collected in the dredge track before

and after each set of tows. Qualitative assessments of the

epifaunal and large-specimen infaunal community were

conducted by divers using still cameras. There was no

control (undredged site) in this study, and thus no means

to statistically evaluate the effects of location or natural

changes on the abundance or composition of the benthic

community in the bay that could have occurred during the

course of this study.

Dredge teeth penetrated the bottom 3-4 cm. Dredging

created furrows, eliminated natural bottom features, and

dislodged large shell fragments and small stones.

Sediments in this location are well-mixed by wave action to

a depth below 3-4 cm, thus the dredge had no effect on the

vertical distribution of grain size, organic carbon, or

chlorophyll a. Grooves and furrows created by the dredge

were eliminated shortly after dredging, the length of time

depending on wave action and tidal conditions.

Infaunal invertebrates that were adapted to the

stresses of a high-energy environment (e.g., amphipods

and bivalve mollusks) were not affected in any significant

way. Sedentary polychaetes declined in abundance after

12 tows, then increased after 25 tows. Small crustaceans --

mostly cumaceans – increased in abundance after the first

two tows and between tows four and twenty-five. There

were no significant changes in biomass of the different

infaunal taxa.

Organisms such as small infaunal crustaceans, crabs,

and starfish were attracted to, and fed on, dead and

damaged organisms left behind the dredge. Visual counts

of living, damaged, and dead epifaunal organisms before

and after each dredging event indicated some damage and

mortality to organisms such as sea urchins, starfish,

scallops, and crabs. Razor clams were dug up by the

dredge and lay partially buried with their valves gaping and

large numbers of sand lances (Ammodytes spp.) were killed.

The plowing effect of the dredge buried, damaged, or

chased away organisms such as brittle stars, burrowing

anemones, and swimming crabs.

7. Thrush et al. (1995) conducted an experimental

study of scallop dredging at two sites 14 km apart in the

Mercury Bay area of the Coromandel Peninsula in New

Zealand in 1991. One site was a commercial scallop fishing

ground and the other site was not. The sediment at both

sites was coarse sand, but was more poorly sorted and had

a large fraction of shell hash at the exploited site. The depth

was about 24 m at each site.

At each site, half of a plot measuring 70x20 m was

dredged (five parallel tows in 1 day) using a 2.4-m-wide box
Page 96

dredge with 10-cm-long teeth on the lower leading edge of

the dredge. Divers collected core samples and made visual

observations in the dredged and undredged halves of each

plot before dredging, within 2 hr after dredging, and 3 mo

after dredging. Results from the two sites were treated

separately because the macrobenthic communities were

distinctly different. Both sites were dominated by small,

short-lived benthic species.

At both sites, the dredge broke down the natural

surface features (e.g., emergent tubes and sediment

ripples), and the teeth created grooves approximately 2-3

cm deep.

Dredging produced changes in benthic community

structure that persisted for 3 mo at both sites. Significant

differences in the numbers of individuals and taxa and in

the densities of common macrofauna (both infauna and

epifauna) were apparent immediately after dredging. The

initial community-level responses at both sites were

negative; there were significantly lower total densities and

numbers of taxa in the dredged half-plots than in the

adjacent reference half-plots.

The responses noted 3 mo later were more complex,

with differences between the two sites. Effects were more

pronounced and more often negative at the previously

unexploited site where total density remained significantly

lower in the dredged half-plot 3 mo after dredging. Six of

the 13 most common taxa at this site were significantly less

abundant in the dredged half-plot plot 2 hr after dredging,

and five of them (i.e., two phoxocephalid amphipods and

three polychaetes) were still less abundant 3 mo later.

In contrast, there was a significant recovery in total

density in the dredged half-plot at the exploited site after 3 mo,

to the point that the total densities in the adjacent half-plots at

that site were the same. Four of the thirteen most common taxa

at this site were significantly less abundant 2 hr after dredging,

and three of them (i.e., ostracods and two species of bivalve

mollusks) still had not recovered 3 mo later. Four taxa that were

negatively affected 2 hr after dredging at the exploited site

were more abundant in the dredged half-plot than in the

control half-plot 3 mo after dredging.

 The authors concluded that the differences in the

recovery processes at the two sites were likely related to

differences in the initial community composition and to

differing environmental characteristics.

Summary

Seven studies of the effects of toothed scallop

dredges on sandy bottom habitat are summarized in this

document, six of them for box dredges in Australia and New

Zealand, and one for Newhaven-style dredges in Scotland

(6). All of the studies except one (5) were published during

the 1990s. Four of the Australian studies (1-4) were done in

the same location (Port Phillip Bay), at three sites that had

not been disturbed by commercial dredging for 4 yr prior to

the beginning of the studies. All were performed in

relatively shallow water (5-24 m). Five of these studies were

controlled experiments, and two (5, 6) were observational in

nature. Three studies (1, 2, 5) examined just physical

effects, and four evaluated both physical and biological

effects. One study (7) compared effects at commercially

exploited and unexploited sites with different benthic

communities.

The Australian experimental studies (1-4) simulated

commercial dredging activity, whereas the New Zealand

study (7) evaluated the effects of multiple side-by-side

tows, and the Scottish study (6) examined the incremental

effects of multiple tows on the same area of bottom. In all

cases, experimental dredging was limited to a single event

that never lasted for more than 1 wk. In those studies (3, 4,

7) in which recovery was monitored, it ranged from 3 mo (7)

to 14 mo (3, 4).

Physical Effects

Physical effects included sediment plumes (which

lasted up to 15 min), the smoothing of the seafloor, tracks

made by dredge skids, and furrows up to 4 cm deep created

by the dredge teeth (1-7). Dredging disturbed bottom

sediments to a maximum depth of 6 cm (1, 2). At a shallow,

high-energy site, there was no effect on sediment

composition, and dredge tracks were obliterated within a

few days (6). At a deeper, less-exposed site, sand ripples

that had been smoothed by dredging reformed within 5

days (4), biogenic mounds were restored after 6-7 mo (3, 4),

and dredge tracks that were still visible after 1 mo had

disappeared after 6 mo (4).

Biological Effects

Biological effects were variable and depended on the

degree of natural disturbance, how well individual species

were adapted to sediment disturbance, and whether a

single dredge tow or multiple tows were made over the

same area of bottom.

Two studies conducted at the St. Leonards site in the

relatively low-energy, enclosed Port Phillip Bay in

Australia showed that the abundance of most infaunal

species was reduced by 20-30% during the first 3.5 mo after

the area was dredged repeatedly during a 3-day period (3,

4). There were no effects of dredging on the total number of

individuals, but there were significantly fewer species in

the dredged plot 3 wk after dredging. Dredging

significantly reduced the densities of six of the ten most

common infaunal taxa, and increased the abundance of

more mobile, opportunistic species within the first 3.5 mo of

the experiment. (Two and three of the ten most common

taxa were significantly reduced in abundance 1-2 days after

dredging at two other sites in the bay [4]).

Research at the St. Leonards site also revealed that the

surface-dwelling infauna is released into the water column
Page 97

right away, whereas burrowing organisms are released

during later dredge tows. Most of the affected species at

the St. Leonards site recovered within 8 mo, but some were

still less abundant after 14 mo.

At two slightly deeper, open coastal sites in New

Zealand, single tows resulted in immediate and significant

decreases in the number of macrobenthic individuals and

species (7). The immediate effects of dredging at an

unexploited site were more pronounced and, for individual

taxa, more often negative (significant reductions in six of

the thirteen most common taxa) than at the site that was

located in a commercial scallop dredging ground

(significant reductions in four of 13 taxa). In addition, at the

exploited site, total abundance was the same in the dredged

and control half-plots 3 mo after dredging, but at the

unexploited site, total density was still significantly higher

in the control half-plot.

Repeated dredge tows in a very shallow, high-energy

location in Scotland significantly increased the abundance

of certain species of small infaunal crustaceans, and

initially reduced but then increased the abundance of

sedentary polychaetes (6). Taxa that are adapted to

dynamic environments (e.g., amphipods and bivalve

mollusks) were not significantly affected. Dredging also

caused considerable damage and mortality to large

epifauna and infauna in this study.

Toothed Scallop Dredges -- Biogenic Substrate

(Table 5.11)

Hall-Spencer and Moore (2000a) described the effects

of scallop dredging on maerl beds, a biogenic substrate

which is derived from living calcareous rhodophytes.

These beds take hundreds to thousands of years to

accumulate because the growth rates of the macroalgae are

very slow and are particularly vulnerable to damage from

mobile bottom fishing gear (Hall-Spencer and Moore

2000b).

Single tows were made at depths of 10-15 m along three

100-m transects in an area in the Clyde Sea (Scotland) that

had been commercially dredged for 40 yr, and as well as

along three 100-m transects in an area of the Clyde Sea that

had been previously undredged. Tows used a gang of

three Newhaven dredges with 10-cm-long, spring-loaded

teeth mounted 8 cm apart on a horizontal metal bar that was

held off the seafloor by a rubber roller at each end.

Immediate effects of dredging were noted and one transect

at each site was monitored by divers 2-4 times a year over

the following 4 yr.

Video recordings showed, at both sites, that the rollers

and chain rings were in contact with the bottom while the

dredge teeth projected fully into the maerl substratum (10

cm) and harrowed the seafloor, creating a cloud of

suspended sediment. Rocks and boulders <1 m3

 in

diameter were dislodged and overturned, and cobbles were

often wedged between the teeth and dragged through the

sediment. Dredges created 2.5-m-wide tracks along which

natural bottom features (e.g., crab pits and burrow mounds)

were erased. Sand and silt was brought to the sediment

surface, and living maerl was buried. Dredge tracks

remained visible for 0.5-2.5 yr depending on depth and

exposure to wave action.

Most megafauna on or within the top 10 cm of the maerl

was either caught in the dredges or left damaged in the

dredge track. Large, fragile organisms (e.g., sea urchins

and starfish) were usually broken on impact, whereas

strong-shelled organisms (scallops, gastropods) usually

passed into the dredge intact. Deep-burrowing species

escaped dredge damage. Predatory species (e.g., whelks,

crabs, and brittle stars) rapidly aggregated in the dredge

track to feed.

Recovery rates for affected benthic species also varied

considerably. Species with regular recruitment and rapid

growth recovered quickly, as did mobile epibenthic species

that migrated into test plots soon after dredging. Slowgrowing species and/or infrequently recruiting sessile

organisms remained depleted on test plots at the

undredged site 4 yr after dredging occurred, whereas the

previously dredged macrobenthic community returned to

pre-experimental status within 2 yr.

Summary

The immediate physical and biological effects of single

dredge tows were evaluated on maerl substrate in Scotland.

Recovery was monitored over 4 yr.

Dredging penetrated the seafloor to a depth of 10 cm,

suspending sediment, overturning boulders, erasing

bottom features, and burying living maerl in dredge tracks.

Some dredge tracks were only visible for 6 mo, while others

remained visible for 2.5 yr, depending on depth and

exposure to wave action.

Most of the megafauna in the top 10 cm of substrate

was either caught in the dredge or left damaged in the

dredge track. Large, fragile organisms were most

vulnerable. Recovery of the epibenthic community was

complete at a previously dredged site within 2 yr, but some

species at an unexploited site still had not recovered after 4

yr. Slow-growing species, and species that infrequently

recruited to the benthos, took much longer to recover than

species with regular recruitment patterns and faster growth

rates.

Toothed Scallop Dredges -- Mixed Substrates (Table

5.12)

1. Bradshaw et al. (2002) compared historical and

recent benthic sample data from seven sites located

south and west of the Isle of Man (in the Irish Sea)

exposed to different amounts of fishing effort since the

late 1930s. Sample data were available for 1938-1952
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when scallop dredging in the area was very limited, and

for the 1990s. Some of these data were analyzed earlier

by Hill et al. (1999).

Analysis of sediment samples indicated that five of the

sites were predominantly sand, and two were gravel. No

depth information was provided. Fishing disturbance for

each site was evaluated in terms of: 1) total fishing effort by

a sample fleet during 1981-1993, and that effort’s inverse

coefficient of variation (i.e., higher values indicate a more

even distribution of fishing disturbance from year to year);

2) the number of years since fishing began; and 3) a

fishermen’s ranked index of total fishing effort at each site

since the start of the fishery. Smallscale (e.g., grab) and

largescale (e.g., trawls) samples were pooled for each site

so that the analysis would include the greatest possible

range of infaunal and epifaunal animals.

There was a significant temporal effect across all sites,

and at two sites where spatial and temporal replicate

samples were available, the historical samples were distinct

from the recent samples. Taxa that decreased in abundance

between the two time periods included species of brittle

stars, hydroids, upright and encrusting bryozoans,

encrusting worms, and barnacles. Taxa that increased in

abundance between the two time periods included largebodied tunicates, mobile crustaceans (shrimp, spider crabs,

and squat lobsters) and robust scavengers (whelks, hermit

crabs, and starfish). Taxa that became more abundant, on

average, scored higher in terms of life history characteristics that would increase their ability to survive dredging

(highly mobile, deep burrowers, scavengers, mud/sand

sediment preference, robust body types, and good

regeneration and recolonization powers) than those that

became less abundant (sessile, shallow burrowers/nest

builders, suspension or filter feeders, shell/stone substrate

preference, fragile body types, and poor regeneration and

recolonization powers).

For individual sites, mean faunal similarities between

the two time periods decreased significantly as the

fishermen’s index of effort and the number of years since

fishing began increased. Similarly, the proportion of

species “lost” between the two sampling periods increased

significantly as the number of years of fishing increased.

Faunal similarities and proportions of lost species between

time periods were not significantly related to increased

fishing effort, as estimated from fishermen’s logbooks.

These results suggested to the authors that it was the

length of time over which fishing occurred, rather than

absolute levels of effort, which was important in

structuring benthic communities.

For all sites, there was also no clear evidence of a

relationship between changes in taxonomic diversity and

fishing effort, although taxonomic distinctness -- probably

the best indicator of changes in biodiversity – decreased

over time at two of the most heavily fished sites.

2. Bradshaw et al. (2000) analyzed density estimates

of epibenthic animals made during diver surveys in the

undisturbed portion of a 2-km2

 area near the Isle of Man, in

the Irish Sea, that was closed to commercial fishing by

towed gear in 1989. The entire area adjacent to and inside

the closed area had been heavily dredged for 50 yr prior to

the closure. Depth in the study area ranged from about 25

to 40 m, and the seafloor was a mixture of gravel, sand, and

mud. The diver surveys started in 1989, the year the area

was closed, and were repeated in 1990 and then in every

other year until 1998.

A number of epifaunal species increased significantly

in abundance over the 9-yr period, including brittle stars, a

spider crab, scallops, hermit crabs, and one species of

starfish. The most significant changes occurred in the fifth,

seventh, and ninth years after the area was closed.

3. Bradshaw et al. (2001) assessed the effects of

scallop dredging on benthic communities inhabiting mixed

substrates in the closed area described in the preceding

review [Bradshaw et al. (2000)]. Two experimental plots

inside the closed area were each dredged every 2 mo or so

from January 1995 to 1998, using two sets of four, springloaded, Newhaven scallop dredges towed 10 times along a

single dredge track. Two control plots were established

inside the closed area. Three additional plots were located

outside the closed area in a commercial scallop dredging

ground. Grab samples were collected twice a year starting

in 1995 in all seven plots.

After the first 6 mo of experimental dredging, benthic

community structure in the experimental plots was more

similar to the commercially dredged plots, and less similar

to the control plots, than it had been before dredging

began. This trend continued over the next 3 yr of the

experiment. However, none of these differences were

significant, nor were there any clear trends for particular

species or groups of species.

Dredging also had no significant effect on total

species numbers or richness, but there was evidence that

dredging reduced benthic community heterogeneity.

Sessile epifaunal organisms were considered to be

especially sensitive to dredging disturbance and were

analyzed separately; one dataset (March 1998) revealed

that encrusting bryozoans, encrusting sponges, and small

ascidians were more common in dredged plots, while

upright forms such as bryozoans and hydroids were more

common in the undredged plots.

4. Caddy (1973) used a two-man submersible to

observe the effects of 0.8-m-wide toothed dredges in

Chaleur Bay, Gulf of St. Lawrence, in August 1971. A gang

of three dredges was attached to a common steel towing

bar. The upper and lower edges of each dredge mouth were

armed with blunt teeth 4 cm long. Observations were made

inside and outside dredge tracks within 1 hr of each tow.

Depth varied from 40 to 50 m, and the substrate was sand

overlaid by glacial gravel and cobble, 1-10 cm in diameter,

with occasional boulders up to 60 cm across embedded in

the gravel.
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Tracks left by these dredges were shallow with a flat

floor. Gravel was sparser inside than outside the track, and

dislodged boulders were commonly observed. Tooth

marks were seen over sandy bottom. Spoil ridges were left

between adjacent dredges, and piles of small rocks were

seen at intervals along the track. Small rocks were also

“bulldozed” along in front of the dredge.

5. The Canadian Department of Fisheries and Oceans

(DFO 1993) conducted a sidescan sonar survey in the Bras

D’Or Lakes system in Nova Scotia to document the

physical effects of various mobile fishing gears 1 yr after

the area was closed to mobile gear. Water depths ranged

from 10 to 500 m.

Dredge tracks consisting of a series of parallel furrows

made by the dredge teeth were observed in gravelly

bottoms and occasionally in silty bottoms. On the older or

degraded dredge tracks, the furrows left by the teeth were

not always resolved. In a soft bottom area, berms were

visible at the outer edges of the dredge track. Similar berms

were not seen in harder bottom areas.

6. Kaiser, Hill, et al. (1996) compared the immediate

effects of beam trawling and scallop dredging on large

epibenthic fauna on a heavily fished scallop ground off the

southwest coast of the Isle of Man, adjacent to the closed

area studied by Bradshaw et al. (2001). Three parallel

waylines, 500 m apart and 1 nmi long, were established: one

was fished 10 times with a 4-m commercial beam trawl fitted

with an 80-mm diamond-mesh cod-end, one was left

undisturbed, and one was fished 10 times with two gangs

of four Newhaven spring-toothed dredges. The benthos in

all three waylines was surveyed using a 2.8-m beam trawl

with a 40-mm square-mesh cod-end before, and 24 hr after,

fishing.

Prior to fishing, there were no significant differences

between the epibenthic communities on the three waylines.

Both gears greatly reduced the abundance of most species

and altered community structure, but there were no

significant differences in community structure between the

two experimental waylines after fishing. The scallop

dredges caught a lower proportion of nontarget species.

7. Kaiser, Ramsay, et al. (2000) examined the

structure of infaunal and epifaunal benthic communities

exposed to either high or low scallop dredging activity,

based on fishing effort data, in the Irish Sea between 1986

and 1996. Samples were collected with an anchor dredge, a

grab sampler, and a small beam trawl from five sites

subjected to low fishing effort, and from five sites

subjected to high fishing effort. Only large infaunal

organisms (>10 mm) were retained in sediment samples

since they were judged more sensitive to physical

disturbance. The study area was located south of the Isle

of Man, in the Irish Sea, in the center of one of the most

heavily fished scallop grounds in Europe, in gravel and

coarse sand sediments.

After accounting for habitat effects (caused by

variations in median sediment grain size and depth), the

only significant response to increased fishing was a higher

number of epifaunal organisms. There were no significant

effects on the number or diversity of epifaunal species nor

on any of the community indices for infauna.

Benthic communities in the heavily fished areas were

dominated by higher abundances of smaller-bodied

species, whereas the less intensely fished areas were

dominated by lower abundances of larger-bodied species.

Species with higher mean densities or catch rates in the

low-effort sites included a soft coral, two species of sea

urchin, a bivalve mollusk, and two gastropods. Species

that were more abundant in the high-effort sites included

three species of brittle star and a sea urchin.

8. Veale et al. (2000) compared samples of epibenthic

organisms collected with a gang of four Newhaven type

spring-toothed scallop dredges in 1995 on 13 commercial

fishing grounds in the Irish Sea that had been exposed to

different amounts of fishing effort during the preceding 60

yr. The dredges were equipped with short teeth (76 mm)

and small belly rings (57 mm). Annual estimates of fishing

effort were available from detailed, high-resolution

fishermen’s logbooks. Depths ranged from 20 to 67 m, and

sediment types were generally coarse sand and gravel,

overlain with pebbles, cobbles, and dead shell.

Of all environmental parameters examined (including

depth and bottom hardness and texture), a combination of

long- and short-term fishing effort best explained the

observed differences in dredge bycatch assemblages

across sampling sites. Species diversity and richness, total

number of species, and total number of individuals all

decreased significantly with increasing fishing effort.

Total abundance, biomass, and production, and the

production of most of the major individual taxa

investigated, decreased significantly with increasing

effort. Species that were more abundant at the high-effort

sites included starfish, soft corals, spider crabs, and the

crab Cancer pagurus. Spider crabs and soft corals were

also more abundant at the medium-effort sites.

Summary

This section summarizes the results of eight studies

that assessed the effects of toothed scallop dredges on

mixed glacially derived substrates. All but one (4) of these

studies were done since 1993. Six of them were conducted

in the Irish Sea and two in eastern Canada. The Canadian

studies (4, 5) examined physical effects to the seafloor, and

the Irish Sea studies evaluated effects on benthic infauna

and epifauna.

Two of the Irish Sea studies (2, 6) were experimental.

One study (1) compared benthic sample data collected at

sites exposed to variable amounts of historical fishing

effort, and another (3) involved diver surveys in a closed
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area. One of the two experimental studies (6) evaluated the

effects of a discrete scallop dredging and beam trawling

event on large epifauna in a commercially exploited area,

and the other (2) examined the incremental effects of

repeated, bimonthly tows over a 3-yr period in a closed

area.

Physical Effects

Physical effects of scallop dredging in mixed

substrates included furrows made by the teeth, shallow,

flat tracks with spoil ridges or berms at the edges,

dislodged boulders, and the “bulldozing” of small rocks by

the dredge (4, 5). No information on recovery times was

available.

Biological Effects

In the closed area study (3), 6 mo of experimental

dredging (total of 30-40 tows per dredge track with eight

dredges on three or four different occasions) following a 6-

yr period with no dredging altered benthic community

structure, but not significantly. There were no trends in the

abundance of individual species or number of species, but

there was evidence of reduced benthic community

heterogeneity. Three years after dredging began, upright

species were less abundant, and encrusting species were

more abundant. (These changes may have occurred earlier,

but this could not be verified). A number of epifaunal

species increased significantly in abundance in the closed

area 5-9 yr after the area was closed (2).

Experimental dredging in commercial fishing grounds

in the Irish Sea altered the community structure of large

epifaunal populations (6), while areas exposed to 10 yr of

high fishing effort were characterized by significantly

higher numbers of epifaunal organisms (7). Chronic

exposure to high fishing effort did not significantly affect

infaunal communities, and there were no significant effects

of increased scallop dredging activity on the number of

epifaunal species or species diversity, but there was a shift

from benthic communities dominated by greater numbers

of larger species to fewer numbers of smaller species (7).

Sites exposed to low fishing activity during the late

1930s to early 1950s, and high fishing activity during the

1990s, were characterized by fewer “disturbance-vulnerable” species and more “disturbance-tolerant” species (1).

Furthermore, faunal differences and the percentage of

species “lost” between the low- and high-effort time

periods increased as the number of years since fishing

began increased. Overall, there was no clear evidence of

reduced species diversity between the two time periods.

Invertebrate bycatch collected in dredges at higheffort sites was composed of significantly fewer species

and individuals than at low and medium-effort sites, and

total abundance, biomass, and production, and the

production of individual taxa declined significantly with

increasing fishing effort (8).

Other Nonhydraulic Dredges

Other Nonhydraulic Dredges -- Biogenic Substrate

(Table 5.13)

1. Fonseca et al. (1984) conducted research near

Beaufort, North Carolina, in 1982 to determine the effects of

small, hand-pulled, bay scallop dredges on eelgrass. Two,

65-cm-wide, lightweight dredges (no teeth on the dredge

foot) were fixed to a single tow bar. Two study sites were

selected, an exposed site with compacted silty sand

sediments (19.8% silt-clay), and a protected site where

sediments were less compact and had a slightly higher siltclay content (22.3%). Three small quadrats at each site

were dredged 15 times, three were dredged 30 times, and

three were not dredged at all.

There was a significant decrease in both the number of

eelgrass shoots and the biomass of eelgrass leaves with

increasing dredging effort at each site. Both shoot number

and leaf biomass were reduced to zero at the soft bottom

site after 30 dredge pulls, but the hard-bottom site lost more

biomass than the soft-bottom site because the initial

biomass there was higher. The proportional reduction in

shoot number was greater at the soft-bottom site.

The authors concluded that intensive scallop

dredging for bay scallops with this gear or with the heavier

dredges that are pulled by powerboats has the potential for

immediate as well as long-term reduction of eelgrass

nursery habitat.

2. Langan (1998) conducted a study in 1994 to

determine the effects of dredge harvesting on an eastern

oyster population and its associated benthic community in

the Piscataqua River, which divides the states of New

Hampshire and Maine. An oyster bed approximately 18

acres in size in the river channel is divided nearly equally by

the border between the two states. Maine allowed

commercial harvesting of oysters, but New Hampshire did

not, for many years prior to the study. The dredge used on

the Maine side of the river was 30 in (76 cm) wide, weighed

approximately 27 kg, had blunt 8-mm teeth, and had a chainmesh bag. Commercial dredging on the Maine side of the

river (with one dredge, about twice a week) had continued

for 5 yr prior to the study. A limited number of benthic

samples were collected by divers on each side of the river

on one sampling occasion. Turbidity was measured during

a single dredge tow.

No significant differences were found in the number,

species richness, or diversity of epifaunal or infaunal

invertebrates between the two areas. The concentration of

suspended sediment in near-bottom water during the
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dredge tow was slightly more than double the ambient level

10 m behind the dredge, and dropped off to the ambient

level 110 m behind the dredge.

3. Lenihan and Peterson (1998) conducted a study in

the Neuse River estuary in North Carolina to determine if

the loss of eastern oysters from the river was in part due to

the lowering of oyster reefs by oyster dredges. Eight, 1-mtall, oyster-shell reefs were constructed in two depths (3

and 6 m). Nineteen months later, four of the eight reefs were

dredged by a commercial dredge vessel for 1 wk until the

catch of market-sized oysters in each haul declined to near

zero and remained constant. The height of harvested and

unharvested reefs was measured 3 days before dredging

started and 2 days after dredging stopped.

Dredging reduced the mean height of the 1-m reefs by

29±6 cm. Unharvested reefs lost only 1±1 cm of height over

the 1-wk duration of the experiment.

4. Riemann and Hoffmann (1991) assessed the effects

on the water column of mussel dredging in a shallow

eutrophic sound (Limfjord) in Denmark that had a mean

depth of 7 m and a maximum depth of 15 m. Suspended

particulate matter, oxygen, and nutrient (phosphorus and

ammonia nitrogen) levels were measured at a number of

stations throughout the water column at a dredged and a

control site before dredging, immediately afterwards, and

30 and 60 min later. No information on sediment type was

given. Dredging was performed for 15 min with a 2-m-wide

mussel dredge weighing about 100 kg.

Average suspended particulate matter increased

significantly immediately after dredging, but returned to

pre-dredge levels 60 min later. Particulate matter also

increased markedly on a day with high wind velocity.

Oxygen decreased significantly immediately after dredging, particularly near the bottom. Average ammonia

content also increased after dredging, but large horizontal

variations prevented detailed interpretation of these

increases.

Summary

Four studies are summarized. Three studies were

conducted on the U.S. Atlantic coast, and one was

conducted in Denmark. All studies were performed in

shallow water, two in rivers and two in coastal waters with

a maximum depth of 15 m. Two studies evaluated biological

effects, one examined physical effects, and one examined

geochemical effects in the water column. Three studies

were experimental and one was observational.

Physical and Biological Effects

These studies showed that dredging lowered the

height of oyster reefs (3) and, in a shallow enclosed fjord,

temporarily increased water column turbidity and lowered

dissolved oxygen concentrations, especially near the

bottom (4). There were no detectable effects after 5 yr of

oyster dredging on benthic invertebrate abundance,

species richness, or diversity (2). Repeated tows with

hand-hauled bay scallop dredges significantly reduced

eelgrass biomass (1).

Hydraulic Clam Dredges

Hydraulic Clam Dredges -- Mud (Table 5.14)

Hall and Harding (1997) evaluated the effects of

experimental suction dredging on intertidal infaunal

communities in Auchencairn Bay, on the north side of the

Solway Firth, on the west coast of Scotland. Sediments

were 60-90% silt-clay in the inner bay and 25-60% silt-clay

in the middle and outer bay. Commercial dredging for the

cockle Cerastoderma edule in the bay was prohibited 4.5

mo before experimental dredging began. Core samples

were collected in control plots prior to each dredge tow,

and in experimental plots immediately after, and 1, 4, and 8

wk after each dredge tow.

Dredge tracks could not be seen after the first day.

The total number of infaunal individuals and species

increased in both plots over time, but were significantly

lower in the experimental plots than in the control plots

immediately after dredging and after 4 wk. Species

diversity also increased significantly over time, but was not

significantly different in the two plots at any point during

the experiment. Three of the five dominant species were

significantly reduced by dredging over the course of the

study. By the end of the study (8 wk), much of the

difference between dredged and control sites had been

lost.

Summary

Results of a single experimental study are summarized.

It examined the physical and biological effects of individual

suction dredge passes in an intertidal mud habitat, and

monitored recovery for 8 wk.

Dredging produced dredge tracks that disappeared

after 1 day. There were significant reductions in the total

number of infaunal individuals and species that lasted 4 wk,

and three out of five dominant species were reduced in

abundance during the entire 8-wk duration of the

experiment. However, infaunal community structure

recovered nearly completely by the end of the experiment.

Hydraulic Clam Dredges -- Sand (Table 5.15)

1. Hall et al. (1990) studied the physical and

biological effects of a commercial escalator dredge used to
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harvest razor clams (Ensis spp.) in a shallow sea loch (Loch

Gairloch) on the west coast of Scotland in November 1989.

The depth at the study site was 7 m, and the sediment was

fine sand. The study site was located near a recently

dredged area, but was not exploited itself. Experimental and

control plots were visually inspected and sampled by

divers immediately after dredging and 40 days later. Each

experimental plot was dredged intensively for approximately 5 hr in order to simulate commercial fishing activity.

After dredging, the experimental plots were crisscrossed by shallow trenches (0.5 m wide and 0.25 m deep)

interspersed with larger holes (up to 3.5 m wide and 0.6 m

deep) that were presumably produced when the dredge

remained stationary for a brief period. Sediment in the

holes and trenches was “almost fluidized,” and sediment in

the fished area had a significantly higher median particle

size than sediment in the control plots. After 40 days,

however, none of these features remained.

The number of infaunal species and individuals were

reduced in the experimental plots immediately after

dredging (significantly, for individuals), but there were no

detectable differences between experimental and control

plots 40 days later. There were no significant differences in

the abundance of individual species in the control and

experimental plots on either sampling occasion.

The authors concluded that dredging caused a shortterm, nonselective reduction in the numbers of all infaunal

species and that recovery from physical effects was

accelerated by a series of winter storms and considerable

sediment disturbance in the study area. No attempt was

made to assess the mortality of: 1) large polychaetes and

crustaceans that were observed to be retained on the wiremesh conveyor belt or that fell off the end of the belt, or 2)

ocean quahogs that were often cracked by the dredge.

2. Kaiser, Edwards, et al. (1996) investigated the

effects of suction dredging for cultivated manila clams

(Tapes philippinarum) [since reclassified and renamed as

Japanese littleneck clam (Venerupis philippinarum)] on a

muddy sand intertidal flat in southeastern England during

December 1994. Samples of benthic infauna and sediment

were collected prior to, 3 hr after, and 7 mo after harvest in

one cultivated plot and in nearby control locations.

There were significantly higher densities of infaunal

organisms in the cultivated plot versus the control plots

prior to dredging, but no differences in the number of

species or in four indices of taxonomic diversity. During

dredging, large amounts of fine sand were resuspended by

the dredge, exposing the underlying clay. Immediately

after dredging, there were significant reductions in the

mean numbers of infaunal species and individuals in the

cultivated plot, resulting in levels that were statistically the

same as in the control plots. Crustaceans and bivalve

mollusks were particularly affected. Seven months later

there were no significant differences between the benthic

community in the harvested plot and in the control plots,

and the proportion of fine sand in the harvested plot had

increased significantly, indicating that recovery from the

effects of clam cultivation and harvesting was complete.

3. MacKenzie (1982) sampled the benthic invertebrate assemblages of three ocean quahog beds with

contrasting fishing histories located about 65 km east of

Cape May, New Jersey, in the MAB, during October 1978.

One bed had never been fished, one had been actively

fished for 2 yr, and one had been fished for about a year but

then abandoned 4-5 mo prior to this study. All three beds

were in very-fine-to-medium sand sediments in 37 m of

water. Commercial dredging was conducted with cage

dredges in this area. Sampling was limited to a total of 30

grab samples from all three sites.

No significant differences were found in numbers of

invertebrate individuals or species, nor in species

composition, between the recently abandoned and never

dredged sites, or between the actively dredged and never

dredged sites. Hydraulic dredging thus did not appear to

have any lasting effect on the invertebrate populations in

these beds. Comparison of samples from the recently

abandoned and never dredged sites also indicated that

hydraulic jetting of the bottom re-sorts bottom sediments,

leaving shell fragments on the surface and coarser

sediments at the bottom of dredge tracks.

4. Maier et al. (1995) assessed the effects of escalator

dredges in four muddy sand tidal creeks in South Carolina

by comparing pre- and post-dredging turbidity levels and

benthic infaunal assemblages. Turbidity was monitored 2

wk before, during, and 2 wk after dredging at one location,

and during and immediately after dredging at another.

Infaunal samples were collected 3 wk before and 2 wk after

dredging in a creek that had been commercially dredged 5

yr prior to the study, and in a creek that had never been

dredged before.

Turbidity was elevated near the dredge and

immediately downstream while it was operating, but the

sediment plumes only persisted for a few hours. Sampling

failed to detect any significant changes in the abundance

of dominant infaunal taxa, or in the total numbers of

individuals, after dredging.

5. Medcof and Caddy (1971) utilized divers and a

submersible to compare the physical effects of a hydraulic

cage dredge in shallow-water (7-12 m) sand inlets in

southern Nova Scotia, Canada.

On sand and sand-mud habitats, hydraulic dredges left

smooth tracks with steeply cut walls that averaged 20 cm

deep, and then slowly filled in by slumping. The hydraulic

dredge raised a sediment cloud that seldom exceeded 0.5 m

high and usually settled within 1 min. Dredge tracks were

still easily recognizable after 2-3 days.

6. Meyer et al. (1981) observed the effects of a small

(1.2-m-wide) hydraulic clam cage dredge in an Atlantic

surfclam bed located near Rockaway Beach on the south
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shore of Long Island, New York. The study was conducted

in 1977, 3 yr after the area was closed to commercial

clamming. The sediment in the study area was fine-tomedium sand covered with a 7.5-cm-thick layer of silt, and

the maximum water depth was 30 m. The study area was

exposed to strong bottom currents that caused considerable movement of sand. As part of a larger study to

evaluate gear performance, the effects of dredging on

bottom substrate and fauna were assessed by divers

during, immediately after, and 2 and 24 hr after, a single 2-

min tow.

The dredge formed trenches that were initially

rectangular, as wide as the dredge, and over 20 cm deep.

Mounds of sand 15-35 cm wide and 5-15 cm high were

formed on either side of the trench. The dredge raised a

cloud of silt 0.5-1.5 m high, which settled within 4 min.

Slumping of the trench walls began immediately after the

tow and became more apparent with time. Two hours after

dredging, slumping of the trench walls had rounded the

depression. After 24 hr, the dredge track was less distinct,

appearing as a series of shallow depressions, and was

difficult to recognize.

The dredging attracted predators, with lady and

Atlantic rock crabs preying on damaged clams, and with

starfish, horseshoe crabs, and moon snails attacking

exposed but undamaged clams. By 24 hr after dredging, the

abundance of predators appeared to have returned to

normal, and the most obvious evidence of dredging was

whole and broken clam shells without meat.

7. Pranovi and Giovanardi (1994) studied the effects

of a 2.7-m-wide hydraulic cage dredge in 1.5-2 m depths in

the Venice Lagoon (Italy, Adriatic Sea). Divers collected

samples of sediment and benthic organisms from

experimentally dredged and control areas at two sites

located inside and outside a commercial fishing ground

immediately after experimental dredging and every 3 wk for

2 mo. A single tow was made at each site.

The dredge created 8-10 cm deep furrows, one of which

was clearly visible 2 mo later. In this study, sediment grain

size was not significantly affected by dredging, although

portions of the fishing ground which had been

predominantly silt and clay 15 yr earlier had a considerably

higher sand content at the time of the study. Hydraulic

dredging in this area often cracks the shells of bivalve

mollusks.

Inside the fishing ground, total numbers and biomass

of benthic infauna and epifauna were significantly reduced

in the experimental plot immediately following dredging.

Densities, especially of small species and epibenthic

species, recovered 2 mo later, but biomass did not. Inside

the fishing ground, there were also fewer species in the

dredged area than in the control area immediately after, and

3 and 6 wk after, dredging, but no differences 2 mo

afterwards. Outside the fishing ground, immediately after

passage of the dredge, there were no significant faunal

differences between dredged and undredged areas.

8. Tuck et al. (2000) examined in March 1998 the

effects of hydraulic dredging on the seafloor and benthic

community in a shallow (2-5 m) site that is located in the

Outer Hebrides (Sound of Ronay) on the west coast of

Scotland, and that was closed to commercial dredging.

Sediments in the study area consisted of moderately well

sorted medium or fine sand, and tidal currents reached

speeds as high as 3 knots. Divers collected core samples

and made observations and video recordings before,

during, and immediately after dredging inside and outside

six dredge tracks, and then returned to re-examine the site 5

days and 11 wk after dredging. The dredge was a

commercial dredge that is used to harvest razor clams and

that employs a hollow blade that protrudes 0.3 m into the

sediment and that has holes to direct pressurized water

forward into the sediment.

Immediately after dredging, the track had distinct

vertical walls and a depth similar to the dredge blade.

However, once the dredge was hauled, the sidewalls

collapsed and the tracks had a flat-bottomed “V” shape.

The sediment within the base of the tracks was fluidized to

a depth of approximately 0.3 m and within both sidewalls to

approximately 0.15 m. The tracks were still clearly visible

after 5 days, but less pronounced, and the depth of

fluidized sediment remained the same. After 11 wk, the

tracks were no longer visible, but 0.2 m of sand was still

fluidized. Immediately after fishing, there was significantly

less silt in the sediments inside the tracks than outside, but

there was no difference after 5 days.

Numerically, the infauna at the study site was

dominated by polychaetes. There was a significant

decrease in the proportion of polychaetes, and an increase

in amphipods, in the dredge tracks within 5 days of

dredging, but not after 11 wk. Bivalve mollusks -- other

than razor clams -- were not affected by dredging. Within a

day of dredging, the total number of species and

individuals was significantly lower in the dredge tracks, but

there was no difference after 5 days. Dredging had an

immediate positive and negative effect on the abundance

of a number of individual species. For some species, the

effect persisted for 5 days, but no effects were detected 11

wk after dredging. Owing to the strong currents, there was

a very sparse epifauna in the area; the only observed effect

of dredging was the attraction of crabs into the area to

scavenge on material disturbed by the dredge.

Summary

Results of eight hydraulic dredge studies in sandy

substrates are summarized. Five studies examined the

effects of “cage” dredges of the type used in the Northeast

Region of the United States (3, 5-8), two examined the

effects of escalator dredges, and one examined the effects

of suction dredges. Three of them were published prior to

1990, and five since then. Four were performed in North

America, one in the Adriatic Sea, and three in the United
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Kingdom. One study was conducted on the U.S.

continental shelf at a depth of 37 m, five in shallower

nearshore waters (1.5-12 m), and two in intertidal

environments. Three studies were observational in nature

(3, 5, 6), and five were controlled experiments (1, 2, 4, 7, 8).

Three studies (2, 3, 7) compared effects in commercially dredged and undredged areas, and four (1, 4, 6, 8)

were conducted in previously undredged areas. Six studies

examined the effects of individual dredge passes (2, 4-8),

one evaluated the effects of repeated passes in the same

area during a short period of time (1), and one compared

infaunal communities in an actively dredged, a recently

abandoned, and an never dredged location (3). Seven

studies examined physical and biological effects, and one

was limited to physical effects (5). All of the biological

studies examined effects to infauna. Recovery was

evaluated in four cases for periods ranging from 40 days to

7 mo (1, 2, 7, 8).

Physical Effects

Hydraulic clam dredges created steep-sided trenches

8-30 cm deep that started deteriorating immediately after

they were formed (1, 5-8). Trenches in a shallow, inshore

location with strong bottom currents filled in within 24 hr

(6). Trenches in a very shallow, protected, coastal lagoon

were still visible 2 mo after they were formed (7).

Hydraulic dredges also fluidized sediments in the

bottom and sides of trenches (1, 8), created mounds of

sediment along the edges of the trench (6), resuspended

and dispersed fine sediment (1, 2, 4-6, 8), and caused a resorting of sediments that settled back into trenches (3). In

one study (8), sediment in the bottom of trenches was

initially fluidized to a depth of 30 cm, and in the sides of the

trench to 15 cm. After 11 wk, sand in the bottom of the

trench was still fluidized to a depth of 20 cm. Silt clouds

only last for a few minutes or hours (4-6).

Complete recovery of seafloor topography, sediment

grain size, and sediment water content was noted after 40

days in a shallow sandy environment that was exposed to

winter storms (1).

Biological Effects

Some of the larger infaunal organisms (e.g., polychaetes and crustaceans) retained on the wire mesh of the

conveyor belt used in an escalator dredge, or that drop off

the end of the belt, presumably die (1). Benthic organisms

that are dislodged from the sediment, or damaged by the

dredge, temporarily provided food for foraging fish and

invertebrates (6, 8). Predator densities returned to normal

within 24 hr in one study (6).

Hydraulic dredging caused an immediate and significant reduction in the total number of infaunal organisms in

three studies (1, 2, 8), and in the number of both infaunal

and epifaunal organisms in a fourth study (7). There were

also significant immediate reductions in the number of

species of infauna in two cases (2, 8), and in the number of

species and biomass of both infauna and epifauna in a third

case (7).

In one study using a hydraulic cage dredge,

polychaetes were the most affected in the short term (7); in

another study using a suction dredge, crustaceans and

bivalve mollusks were the most affected in the short term

(2). Two studies of the effects of escalator dredging failed

to detect any reduction in the abundance of individual taxa

(1, 4). In one of them (4), dredging did not reduce the

number of infaunal organisms. Evidence from the study

conducted off the New Jersey coast indicated that the

number of infaunal organisms and species, and the species

composition, were the same in actively dredged and never

dredged locations (3).

Recovery times for infaunal communities were

estimated in four studies. Three of these studies (1, 7, 8)

were conducted in very shallow (1.5-7 m) water, and one (2)

in an intertidal environment. Total infaunal abundance and

species diversity had fully recovered only 5 days after

dredging in a location where tidal currents reach maximum

speeds of 3 knots (8). In the latter study, all species which

had been initially reduced due to dredging had recovered

after 11 wk. In another study, total abundance recovered 40

days after dredging (when the site was first revisited) at a

site exposed to winter storms (1). Total infaunal

abundance, but not biomass, recovered within 2 mo at a

commercially exploited site, but not at a nearby unexploited

site (7). Full recovery at the intertidal site was noted when

it was first revisited 7 mo after it was suction dredged (2).

Actual recovery times at this site and at one of the exposed

subtidal sites (1) may have been much quicker than 7 mo

and 40 days.

Hydraulic Clam Dredges -- Mixed Substrates (Table

5.16)

Murawski and Serchuk (1989) used manned

submersibles to observe effects of hydraulic dredging on

sand, mud, and gravel bottom habitats in a number of

offshore locations in the MAB between Delaware Bay and

Long Island (water depths not reported).

They reported that hydraulic cage dredges penetrate

deeper into the sediments and, on a per-tow basis, result in

greater short-term disruption of the benthic community and

underlying sediments than do scallop dredges (no data

were provided). In coarse gravel, the sides of hydraulic

dredge trenches soon collapsed, leaving little evidence of

dredge passage. There was also a transient increase in

bottom-water turbidity. In finer-grained, hard-packed

sediments, tracks persisted for several days after dredging.

Nonharvested benthic organisms (e.g., sand dollars,

crustaceans, and polychaetes) were substantially disrupted by the dredge. Sand dollar assemblages appeared
Page 105

to recover quickly, but short-term reductions in infaunal

biomass were considered likely. Numerous predatory fish

(e.g., red hake, spotted hake, and skates) and invertebrates

(Atlantic rock crabs and starfish) were observed

consuming broken quahogs in and near dredge tracks.

Densities of crabs and starfish were estimated to be twoand-a-half times higher in dredge tracks than in nearby

undredged areas within 1 hr of experimental tows, and >10

times higher 8 hr after dredging. Presumably, the benthic

infauna “tilled up” by the dredge was also being

consumed, since not all predators observed foraging in the

dredge paths were eating damaged shellfish.

Summary

An in situ evaluation of hydraulic dredge effects in

sand, mud, and coarse gravel in the MAB indicated that

trenches fill in quickly -- within several days in fine

sediment, and more rapidly than that in coarse gravel.

Dredging dislodged benthic organisms from the sediment,

attracting predators.

Hydraulic Clam Dredges -- Biogenic Substrate

(Table 5.17)

1. Godcharles (1971) experimentally evaluated the

physical effects of escalator dredging in seagrass

(Thallasia testudinum and Syringodium filiforme) beds,

Caulerpa algae beds, and bare sand bottoms (depth not

given) in Tampa Bay, Florida, in 1968. Dredging was

conducted with a commercial dredge at six sites. Water jets

penetrated sediments to a maximum depth of 45 cm and left

trenches that varied from 15 to 45 cm deep.

Trenches were deeper in shallow areas where propeller

wash scoured loose sediments from trenches and

prevented redeposition of suspended sediments. The

proportion of fine sediment in some trenches decreased

immediately after passage of the dredge. Virtually all

attached vegetation in the path of the dredge was

uprooted, leaving open bottom areas.

Trenches in grass beds remained visible the longest

(up to 86 days), while those in sandy areas filled in

immediately. Most fluidized sediments hardened within 1

mo, but some spots were still soft 500 days after dredging.

Differences in silt-clay content between tracks and

undisturbed areas became negligible after a year, but

seagrasses had still not recolonized disturbed areas. New

algal growth was noted in some dredged areas after 86

days, and after 1 yr, dredge tracks were completely

covered.

2. Orth et al. (1998) assessed damage to submerged

aquatic vegetation caused by escalator dredges in

Chincoteague Bay, Virginia, during 1996, 1997, and 1998.

They reported a large number of circular “scars” in the

vegetation, with 70-100% seagrass cover outside the

scarred areas, and an abrupt reduction to 15% or less at the

scar edge. The percent cover of seagrass was low across

the scar except for an abrupt increase in cover at the center,

where seagrass had not been disturbed.

There were no measurable differences in percent cover

estimates in the scarred portions of areas that were dredged

during the 3 yr of observation, indicating that revegetation

was proceeding very slowly. There were two factors that

the authors believed were delaying revegetation: an

increase in depth of 10-20 cm in the dredge tracks, and large

holes inside the unvegetated portions of the scars made by

organisms such as foraging cownose rays. The authors

concluded that even the most lightly effected areas would

require a minimum of 5 yr to fully recover.

Summary

Two studies were performed in the southeastern

United States in shallow, subtidal, vegetated habitats. One

study was a controlled experiment that compared the

effects of escalator dredges in vegetated (seagrass and

algae) and unvegetated areas; the other study evaluated

damage to seagrass beds caused by commercial escalator

dredging.

In the experimental study (1), water jets penetrated

sand substrate to a maximum depth of 45 cm, created

trenches up to 30 cm deep, uprooted vegetation, and

decreased the proportion of fine sediments in dredge

tracks. Recovery times were extremely variable. In some

cases, trenches were visible for only 1 day, and in other

cases for 3 mo. In most cases, sediments hardened within 1

mo, but in some tracks, sediments were still fluidized 500

days after dredging. After 1 yr, sediment composition in

dredge tracks had returned to normal, but seagrass had not

recolonized disturbed areas.

In the observational study (2), there were no signs of

recovery of seagrass in commercially dredged areas 3 yr

after dredging.

Pots and Traps

Pots and Traps -- Mixed Substrates (Table 5.18)

Eno et al. (2001) evaluated the effects of crab and

lobster pots on attached epibenthic megafauna (sponges,

bryozoans, ascidians, soft corals, and tube worms) at three

locations in Great Britain: one each off Scotland, Wales,

and England.

Off the west coast of Scotland (Badentarbet Bay), the

effects of dropping pots onto sea pens were observed by

divers in a soft-mud, pot fishing ground for Norway lobster

(Nephrops sp.) in 1995. In addition, three experiments were
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conducted to assess sea pen survival and recovery

following dragging, uprooting, and smothering by lobster

pots. In one experiment, divers dragged pots over marked

areas of the seafloor and recorded the fate of sea pens for 3

days after the disturbance. In the second experiment,

groups of sea pens removed from the seafloor by the pots

were relocated to an undisturbed location, and their

behavior and survival were observed over a 4-day period.

In the third experiment, 60 pots were dropped onto

individual or small groups of sea pens and then removed

after 24 or 48 hr to simulate the effects of smothering that

would occur during commercial operations.

Video observations at the Scottish site showed that

the pressure wave created by pots as they sink to the

bottom was sufficient to bend sea pens away from the pot

just before contact. Results of the three experiments

revealed that all sea pens were able to fully recover from pot

impact. Furthermore, all sea pens recovered from the

effects of dragging within 24-72 hr. Uprooted sea pens

reinserted themselves into the sediment, providing the

peduncle gained contact with the mud surface. Following

smothering for either 24 or 48 hr, it took 72-96 and 96-144 hr,

respectively, for all three species of sea pen to fully recover

an upright position.

At five coastal sites in Lyme Bay, southwest England,

SCUBA divers assessed the immediate effects of pot

hauling in different habitats at depths of 14-20 m in

September and October 1995. Habitats varied from exposed

limestone slabs and bedrock covered by sediment, to large

boulders with mixtures of various rocky substrates

interspersed with coarse sediment. A variety of fragile

epifaunal species, including a sea fan and Ross coral, were

present. Two lines of three pots were deployed at each site.

Divers videorecorded pots as they landed on the seafloor,

and as they were hauled back, and then videorecorded

back along the path of each pot after its removal.

There were very few signs of effect on epifaunal

species at any of the five sites. Gorgonians (soft corals)

were frequently seen to bend under the weight of pots,

then spring back once the pots had passed. When pots

were hauled back along the bottom, a track was left in the

sediments.

At Greenala Point, Wales, and in Lyme Bay, the effects

of potting on selected epibenthic species were quantified

by diver observations at sites with rocky substrates, water

depths <23 m, and fragile epifaunal species. Common

epifaunal species included a sea fan and a colonial

emergent bryozoan. A commercial pot fishery for crabs

(Cancer pagurus) and lobsters (Homarus gammarus) was

carried out in these two locations. Each location was

divided into two control and two experimental plots. Pots

were set in the experimental plots and hauled every 2 or 3

days for 4 wk, such that at least 30 pots and 10 anchor

weights landed in each experimental plot over the course of

the study.

At the Greenala Point site, the abundance of four

sponge species increased significantly in the experimental

plots after 4 wk of potting, but not in the control plots. At

the Lyme Bay site, one species of sponge, an ascidian, and

a bryozoan increased significantly in abundance in the

experimental plots only.

Summary

Observations and experiments were carried out in a

single study conducted at three coastal locations in Great

Britain to evaluate the effects of crab and lobster pot

fishing on attached epibenthic megafauna. Sea pens

underneath pots were bent over and some were uprooted

when pots were dragged over mud sediments, but they

fully recovered within 72-144 hr after pots left on the

bottom for 24 or 48 hr were removed. When pots were

dragged over the bottom they left tracks, but 4 wk of

simulated commercial pot fishing had no negative effect on

the abundance of attached benthic epifauna. In fact, seven

taxa (five sponges, an ascidian, and a bryozoan) increased

in abundance after 4 wk of fishing..

Multiple Gear Types

Multiple Gear Types -- Sand (Table 5.19)

1. Almeida et al. (2000) surveyed the southern half of

Closed Area II on Georges Bank in June 1999, 4.5 yr after

that area was closed to gear used to catch groundfish

(bottom trawls, scallop dredges, longlines, and gill nets).

This portion of the closed area ranges in depth from

slightly <50 m to slightly >90 m, the substrate is sand, and

there are sand ripples and bedforms in the shallower,

northwest, “high-energy” portion of the survey area where

bottom tidal currents are stronger. These features are

generally absent from the deeper (>65 m), “low-energy,”

southeast portion of the survey area. Still photographs

and video imagery were used to assess the relative

abundance of seven microhabitats at a series of paired

stations just inside and outside the closed area boundary.

No significant differences were found for any

microhabitat type except for the emergent sponge epifauna

(e.g., Suberites ficus and Polymastia sp.) microhabitat type

that was more abundant inside the closed area.

2. Kaiser, Spencer, et al. (2000) sampled infauna and

epifauna with a 2-m beam trawl and an anchor dredge along

the south Devon coast in England of three high-fishingeffort areas open to all fishing (otter trawl, beam trawl,

scallop dredge, and pots), in two medium-fishing-effort

areas open to mobile gear for 6 mo out of the year and to

pots year-round, and in one low-fishing-effort area only

open to pots. Sampling within each of the six areas was

distributed among three sites. At each trio of sites,

sediments followed a gradient from fine sand to medium

sand to coarse-medium sand. Fine-sand sites (inshore)
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were located in 15-17 m depths. The medium sand and

coarse-medium sand sites (offshore) were located in 53-70

m depths.

For epifauna, there were significant habitat effects

(i.e., depth and substrate) on the numbers of species and

individuals, and on two indices of species diversity, but

there were no significant fishing effort effects (high versus

low) on any of these parameters. In general, however, as

fishing disturbance increased, less mobile, larger-bodied,

and more fragile epifaunal species decreased in abundance,

while mobile, more resilient species increased in abundance. Areas closed to draggers had higher abundances of

emergent fauna (i.e., soft corals and hydroids) that

increased habitat complexity.

For infauna, there were significant habitat effects (i.e.,

depth and substrate) on the number of species and on one

index of species diversity between the two offshore sites,

but no consistent fishing effort effects across all three

sites, and only one significant fishing effort effect (on

species diversity) between the two deeper offshore sites

(i.e., greater effect at the coarse-medium sand sites).

Infaunal biota in the three different habitats were affected

to different extents by increasing levels of fishing. In

particular, the deeper, medium-coarse sand habitat seemed

most severely affected by fishing. Several infaunal species

in this habitat had significantly lower biomasses and

abundances.

Areas subjected to low fishing effort were dominated

by epifaunal and infaunal species with relatively high

biomass, whereas areas subjected to high fishing effort had

fewer high-biomass species and greater abundances of

smaller-bodied species.

Summary

The results of two observational studies of multiple

gear types on sand habitats (at depths that varied from 15

to >90 m) are summarized. A recent study in U.S. waters on

eastern Georges Bank (1) compared the amount of cover

provided by different habitat types inside and outside an

area closed to trawls, dredges, longlines, and gill nets for

4.5 yr. Another recent study (2) compared sandy shallow

and deepwater sites on the south coast of England that

were exposed to low, medium, and high levels of fishing

effort by mobile and fixed gears.

On Georges Bank, the only significant difference was a

higher abundance of emergent sponges inside the closed

area (1). On the south coast of England, low-effort areas

that were closed to trawls and dredges had more emergent

epifauna (soft corals and hydroids) and were dominated by

relatively high-biomass epifauna and infauna, whereas

high-effort areas fully exposed to fixed and mobile gears

had higher abundances of small-bodied organisms (2).

Deep (53-70 m), coarse-medium sand, offshore sites were

more affected by fishing than deep, medium sand, offshore

sites, or shallow (15-17 m), fine-sand, inshore sites (2).

Multiple Gear Types -- Gravel/Rock (Table 5.20)

1. Collie et al. (1997) sampled two relatively shallow

(42-47 m) and four relatively deep (80-90 m) gravel sites in

U.S. and Canadian waters on the northern edge of eastern

Georges Bank during two cruises in 1994. Bottom

substrates at the sites were predominantly pebble-cobble

with or without encrusting organisms, with some overlying

sand. The sites were classified as disturbed (D) or

undisturbed (U) by bottom-tending mobile gear based on

the number of dredge and trawl tracks in sidescan sonar

images, the presence or absence of large boulders and

epifauna in bottom photographs, and 1993 records of

scallop dredging effort in TMSs of latitude and longitude in

U.S. waters on the bank. There were three U sites and one

D site in deep water, and one U and one D site in shallow

water.

Quantitative samples of epibenthic organisms (>10

mm) were collected with a 1-m-wide naturalist dredge fitted

with a 6.4-mm square-mesh liner. Organisms such as

colonial sponges, bryozoans, hydroids, and the tubedwelling polychaete Filograna implexa that were not

quantitatively sampled by the dredge were excluded from

analysis.

There were significant effects of fishing and depth

combined on total density, biomass, and an evenness

diversity index based on abundance, as well as some

evidence of a gradient in abundance, biomass, and species

diversity from deep undisturbed sites (high values) to

shallow disturbed sites (low values). However, because of

the significant depth effects and depth-disturbance

interactions, fishing disturbance alone was not a

significant factor.

Cluster analysis identified a group of six species that

were abundant at U sites, rare or absent at D sites, and not

affected by depth. This group included two species of

shrimp, a tube-dwelling polychaete, a nemertean, horse

mussels, and a bloodstar. Six other species groups were

defined by either depth or some combination of depth and

disturbance level, or included species that were ubiquitous.

2. Collie et al. (2000), in a follow-up publication,

analyzed video images and still photographs recorded at

five of the six study sites surveyed in the two 1994 research

cruises to George Bank (i.e., one of the deep U sites was not

included).

In the videotapes, the U sites at both depths had

slightly coarser sediments (higher frequency of pebblegravel than sand-gravel); in the still photos, there was a

higher frequency of sand and cobble in U sites and a lower

frequency of pebbles. Bottom photos showed a high

percent cover of colonial hydroids and bryozoans at one of

the deep U sites, and of the rock encrusting polychaete

Filograna implexa, at both deep U sites. In contrast, at the

D sites, the gravel was free of epifaunal cover, and few

animals were visible. Statistical analysis confirmed that the
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U sites had a significantly higher percent cover of

Filograna implexa. However, cover provided by this

species was also significantly greater in deeper water than

in shallow water.

Emergent hydroids and bryozoans were significantly

more abundant at the deep U sites than they were at the

shallow U site. Overall, the percent cover of all emergent

epifauna was significantly higher at the deep sites, but

there was no significant disturbance effect.

Summary

Two recent observational studies of mobile gear

effects on sediments and epifauna in gravel bottom habitat

on the northern edge of eastern Georges Bank (42-90 m) are

summarized. Study sites were distinguished by depth and

the presence or absence of fishing disturbance. Sediments

in undisturbed sites were slightly coarser with more sand

and cobble. There were significantly more organisms,

higher biomass, and greater species diversity at the

undisturbed sites in both depths, but there were also

significantly higher values in disturbed and undisturbed

deep sites than in disturbed and undisturbed shallow sites.

Percent cover of an encrusting colonial polychaete

was also significantly higher at the deep sites and at the

undisturbed sites. Emergent hydroids and bryozoans were

significantly more abundant in deep undisturbed sites, and

at shallow disturbed sites. Overall, emergent epifauna was

more abundant in deep water, but there was no significant

disturbance effect.

Multiple Gear Types -- Mixed Substrates (Table 5.21)

1. Auster et al. (1996) used a remotely operated

vehicle (ROV) in July 1993 to compare conditions inside

and outside an inshore area (depth 30-40 m) in the GOM

that was closed to mobile fishing gear in 1983. On sandshell bottom, video transects indicated that habitat

complexity was provided mostly by sea cucumbers

attached to shell and other biogenic debris, and by bottom

depressions created by mobile fauna. Both of these habitat

features were significantly less common outside the closed

area, a difference that was attributed to the incidental

exploitation of sea cucumbers and the harvest of lobsters,

sea scallops, crabs, and white hake -- all animals that

produce depressions.

On cobble-shell bottom, habitat complexity was

provided mostly by emergent epifauna (i.e., hydroids,

bryozoans, sponges, and serpulid worms) and sea

cucumbers. These species were less common outside the

closed area. Their reduced abundance was attributed to

removal by mobile fishing gear.

Cleared swaths in epifaunal cover were observed at the

border of the closed area and were presumed to be caused

by scallop dredges and trawl doors.

Auster et al. (1996) also conducted sidescan sonar

surveys and ROV observations of Stellwagen Bank (GOM)

in 1993 (depth 20 -55 m). The sonar images showed that

showed large expanses of sand, gravelly sand, shell

deposits, and gravel. The authors reported that waves

produced by large storms from the northeast create ripples

in coarse sand that measure 30-60 cm between crests and

10-20 cm in height, and deposit large sheets of fine sand

with low sand waves 15-35 m between crests. The troughs

of these sand waves are filled with shell debris (mostly

ocean quahogs). Examination of the sonar images also

showed scallop dredge and trawl tracks that disturbed

sand ripples and dispersed shell deposits.

The ROV observations on Stellwagen Bank’s crest (32-

43 m deep) indicated that aggregations of emergent

hydrozoans were missing, and that benthic microalgal

cover was disturbed in gear tracks. Observations on the

crest of the bank in July 1994 showed that an ascidian

species was widely distributed, but was not present in otter

trawl tracks.

2-4. Reise (1982), Riesen and Reise (1982), and

Reise and Schubert (1987) compared invertebrate surveys

in the Wadden Sea (Netherlands) made between 1869 and

1986. Bottom sediments in these areas currently range from

mud to coarse sand and some pebbles. The area is made up

of tidal flats, shallow subtidal banks, and channels that

reach depths of 23 m. Surveys were completed using

oyster dredges and grabs.

During the time period encompassed by the various

surveys, abundant oyster reefs were overexploited,

seagrass beds were lost to a natural epidemic, and

Sabelleria reefs were destroyed by heavy trawl gear. The

area is now dominated by soft sediments and mussel beds,

which prior to 1920 were restricted to very shallow water.

Comparisons show that 28 mollusk and amphipod species

(including eight associated with oyster beds, eight with

Sabelleria, and seven with seagrasses) have declined in

abundance. Twenty-three species (many of them

polychaetes) that were missing or rare in earlier surveys

were common in 1986. The epifauna was more abundant in

the 1920s, and the infauna was more abundant in the 1980s.

5. Thrush et al. (1998) tested 10 predictions regarding

the effects of increasing fishing pressure on benthic

communities in the Hauraki Gulf, New Zealand. Core, grab,

and suction dredge samples were taken from 18 stations

exposed to varying levels of commercial fishing effort by

otter trawls, Danish seines, and toothed scallop dredges.

Additional data were obtained from video images using an

ROV, and from sediment samples collected by divers.

Sediments ranged from sand (<1% silt and clay) to mud

(nearly 50% silt-clay) and depths from 17 to 35 m.

After accounting for the effects of location, depth, and

sediment characteristics (grain size and organic matter

content), 15-20% of the variability in macrofauna (>0.5 mm)

community composition was attributed to fishing pressure.
Page 109

Most of the predictions were supported by analysis of the

core-sample data; fewer predictions were supported by

other sample types. Three predicted results of increasing

fishing pressure were confirmed at P<0.05: decreased

density of large epifauna (video transects), decreased

species diversity and richness (core samples), and

decreased density of echinoderms (cores). Four additional

predictions were confirmed at P<0.10: decreased number of

individuals (grabs), increased density of small opportunistic species (cores), decreased density of long-lived surface

dwellers (cores), and increased density of deposit feeders

(cores). The large members of the epifauna were also less

abundant in grab samples collected from more heavily

fished sites (P <0.10).

Results, in some cases, were not consistent among

sample types. Species diversity and richness, for example,

were not even identified as significant model variables in

the grab sample data, nor was the number of individuals in

the core samples, and deposit feeders collected in grab

samples were significantly less abundant at sites exposed

to increased fishing pressure.

Two predictions were contradicted by the results of

this study: the ratio of polychaetes to mollusks (in cores)

decreased rather than increased with greater fishing

pressure, and the ratio of small to large individuals, for one

common species of sea urchin, increased rather than

decreased (also in cores). Further, scavengers (large,

mobile benthic organisms such as crabs and starfish) were

predicted to increase with increasing fishing pressure, but

there was no evidence from this study that they responded

either positively or negatively to changes in fishing

intensity.

6. Valentine and Lough (1991) used sidescan sonar

and a submersible to describe the effects of scallop

dredges and bottom trawls on sand and gravel habitats on

eastern Georges Bank. They noted that the most evident

signs of disturbance occurred on gravel pavement where

they observed long, low mounds of gravel that presumably

had been produced by trawling and dredging. In some

areas, the seafloor was covered by trawl and dredge tracks.

Gravel areas that were not accessible to bottomtending mobile gear (due to the presence of large boulders)

had a biologically diverse community with abundant

attached organisms. Conversely, the attached epifaunal

community was sparse, and the bottom was smoother, in

areas that had been disturbed by dredging and trawling.

Summary

Six observational studies of the effects of multiple gear

types on mixed substrates are summarized. Surveys were

conducted in the GOM inside and outside an inshore area

closed to mobile fishing gear, and in an offshore area that

was disturbed by mobile fishing gear (1). A series of three

publications examined long-term (100+ yr) changes in

benthic habitats and communities in the Wadden Sea,

some of which were attributed to fishing (2-4). A study in

New Zealand (5) tested 10 predictions of how increasing

fishing activity affects benthic communities by comparing

benthic samples and underwater video footage from areas

exposed to varying degrees of commercial fishing effort. A

sixth study (6) examined areas on eastern Georges Bank

that were affected by mobile bottom gear.

Significant increases were observed in the abundance

of sea cucumbers and emergent epifauna, and in the

number of bottom depressions created by organisms such

as lobsters, sea scallops, and crabs, on sand-cobble-shell

substrate inside the GOM closed area (1). Sidescan sonar

and ROV surveys of Stellwagen Bank revealed evidence

that otter trawls and New Bedford-style scallop dredges

disturb sand waves and ripples, disperse shell deposits,

remove emergent epifauna, and disturb microalgal cover

(1). Disturbed sand and gravel areas of Georges Bank were

characterized by trawl and dredge tracks, sparse epifauna,

mounds of gravel presumably produced by fishing gear,

and smoother bottom (6). In the New Zealand study (5),

there were four significant effects of increased fishing

activity by bottom trawls, Danish seines, and toothed

scallop dredges in mud and sand substrates that were

consistent across all sampling methods. These effects

were reduced density of large epifauna, echinoderms, and

long-lived surface-dwelling organisms, and an increased

density of small, opportunistic species. The loss of

biogenic reefs and changes in benthic community

composition (fewer mollusk and amphipod species and

more polychaete species) in the Wadden Sea were in part

attributed to fishing activity (2-4).
Page 110

Table 5.1. Number of studies included in this review, by gear and substrate type. (PR = peer-reviewed; NPR = non-peer-reviewed.)

Gear Substrate 1990-2002 Pre-1990 Total

 PR NPR Total PR NPR Total 

Mud 9 2 11 0 0 0 11 

Sand 10 2 12 1 0 1 13 

Gravel/Rock 2 0 2 1 0 1 3 

Mixed 1 1 2 0 1 1 3 

Otter Trawls 

All 22 5 27 2 1 3 30 

Sand 3 0 3 0 0 0 3 

Mixed 1 0 1 2 0 2 3 

NB Scallop Dredges 

All 4 0 4 2 0 2 6 

Sand 6 0 6 0 1 1 7 

Biogenic 1 0 1 0 0 0 1 

Mixed 6 1 7 1 0 1 8 

Toothed Scallop Dredges 

All 13 1 14 1 1 2 16 

Mud 1 0 1 0 0 0 1 

Sand 4 1 5 2 1 3 8 

Biogenic 0 1 1 0 1 1 2 

Mixed 0 0 0 0 1 1 1 

Hydraulic Clam Dredges 

All 5 2 7 2 3 5 12 

Other Dredge Biogenic 2 1 3 1 0 1 4 

Sand 2 1 3 0 0 0 3 

Gravel/Rock 2 0 2 0 0 0 2 

Mixed 2 1 3 3 0 3 6 

Multiple Gears 

All 7 1 8 3 0 3 11 

Lobster Pots Mixed 1 0 1 0 0 0 1 

 

Total All 53 11 64 11 5 16 80
Page 111

Table 5.2. Number of studies included in this review, by substrate type. (PR = peer-reviewed; NPR = non-peer-reviewed.)

Substrate 1990-2002 Pre-1990 Total

 PR NPR Total PR NPR Total 

Mud 10 2 12 0 0 0 12 

Sand 25 4 29 3 2 5 34 

Gravel/Rock 4 0 4 1 0 1 5 

Biogenic 3 2 5 1 1 2 7 

Mixed Substrate 11 3 14 6 2 8 22 

 

Total 53 11 64 11 7 18 80

Table 5.3. Number of studies included in this review, by geographical area. (PR = peer-reviewed; NPR = non-peer-reviewed.)

Gear Northeast

Region

Other 

North America 

Europe and

Scandinavia

Australia and

New Zealand Total

Bottom Otter Trawl 7 10 8 5 30 

New Bedford Scallop Dredge 4 2 0 0 6 

Toothed Scallop Dredge 0 2 8 6 16 

Hydraulic Clam Dredge 2 5 5 0 12 

Other Dredge 3 0 1 0 4 

Multiple Gears 5 0 5 1 11 

Lobster Pot 0 0 1 0 1 

 

Total 21 19 28 12 80
Page 112

Table 5.4. Effects of otter trawls on mud substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) 

No. Reference Location Depth Sediment Effects Recovery Approach

1 Ball et al. 2000 Irish Sea 75 m Sandy silt Reduced infaunal and epifaunal richness, 

diversity, number of species, and individuals in fishing ground compared to wreck site, but no obvious effects on macrofauna 24 hr after trawling. 

 Experimental trawling in heavily 

fished prawn fishing ground, unfished area near a shipwreck used as control. 

2 Brylinsky et al.

1994

Bay of Fundy, Nova 

Scotia, Canada 

Intertidal Silt and coarse 

sand overlain 

with silt 

Door tracks in sediment, rollers compressed sediment; S decrease in nematodes and benthic diatoms in door tracks, no effects on larger infaunal organisms (mostly polychaetes). 

Furrows visible 2-7 mo; nematodes recovered in 1-1.5 mo, diatoms in about 1-3 mo. 

Four trawling experiments (repeated tows during a single day) at two locations in a trawled area, effects evaluated for 1.5-4 mo. 

3 DeAlteris et al.

1999 

Narragansett Bay, 

Rhode Island, USA 

14 m Mud Doors produced tracks 5-10 cm deep and 

adjacent berm 10-20 cm high. 

No changes in hand dug trenches for >60 days. 

Diver observations. 

4 Drabsch et al.

2001

Gulf of St. Vincent, 

South Australia 

20 m Fine silt Trawl door tracks, smoothing of topographic 

features; S decrease in total infaunal abundance and one group of polychaetes, damaged epifauna. 

 Experimental trawling (two tows 

per unit of area in 1 day) in area with no trawling for 15 yrs (one site); effects evaluated after 1 wk.

5 Frid et al. 1999 Northeast England 

(North Sea) 

80 m Silt-clay S increase in total number of individuals in 

taxa predicted to increase at high fishing effort and number of errant polychaetes; no effect of increasing effort on total number of individuals expected to decrease, but S decline in sea urchins. 

 Related changes in benthic fauna 

in a heavily trawled location to low, high, and moderate fishing activity and to changes in phytoplankton production over 27 yr. 

6 Hansson et al.

2000

Fjord on the west 

coast of Sweden 

75-90 m Clay Abundance of 61% infaunal species 

negatively affected and S reductions in abundance of brittle stars during last 5 mo of disturbance period; S reductions in total biomass at 3 of 3 trawled sites and 1 of 3 control sites, and in number of individuals at 2 of 3 trawled sites and 1 of 3 control sites; abundance of polychaetes, amphipods, and mollusks not affected. 

 Experimental trawling for 1 yr 

(two tows per wk, twenty-four tows per unit of area) in area closed to fishing for 6 yr (three treatment and three control sites); effects evaluated during last 5 mo of experiment. 

7 Mayer et al. 1991 Maine coast, USA 20 m Mud Dispersal of fine surface sediment; doors 

made furrows several cm deep; some planing of surface features, but no plowing of bottom or burial of surface sediments. 

 Experimental trawling (single 

tow); examined immediate effects on sediment composition and food value to sediment depth of 18 cm. 

8 Pilskaln et al.

1998

Gulf of Maine, USA 250 m Mud Greater abundance of suspended infaunal 

polychaetes in more heavily trawled area. 

 Deployed sediment traps in 

fishing grounds 25-35 m above substrate. 

9 Sanchez et al.

2000

Coast of Spain, 

Mediterranean Sea 

30-40 m Mud Door tracks in sediment; no change in number 

of infaunal individuals or taxa, or in abundance of individual taxa; no changes in community structure. 

Door tracks still clearly visible after 150 hr. 

Experimental trawling in trawled area at two sites swept once and twice in a single day; effects evaluated after 24, 72, 102, and 150 hr. 
Page 113

Table 5.4 (cont.). Effects of otter trawls on mud substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) 

No. Reference Location Depth Sediment Effects Recovery Approach

10 SparksMcConkey and 

Watling 2001 

Penobscot Bay, 

Maine, USA 

60 m Mud S decline in porosity, increased food value, 

and increased chlorophyll production of surface sediments; S reductions in number of infaunal individuals and species, species diversity, and abundances of 6 polychaete and bivalve species, S increase in nemerteans. 

All geochemical sediment properties and all but one polychaete/bivalve species recovered within 3.5 mo, nemerteans still more abundant after 5 mo. 

Experimental trawling (four tows in 1 day) in untrawled area; pretrawl sampling of sediments and infauna for a year; recovery monitored for 5 mo. 

11 Tuck et al. 1998 West coast of 

Scotland 

30-35 m Fine silt Tracks in sediment, increased bottom 

roughness; no effect on sediment characteristics; S increase in number of infaunal species at end of 16 mo disturbance period and during 18 mo recovery period; no change in biomass or number of individuals at end of recovery period; S increase in polychaetes, S decrease in bivalves; mixed results of analyses of community structure, S reduction in diversity during first 22 mo. 

Door tracks still evident after 18 mo; bottom roughness recovered after 6 mo; nearly complete recovery of infaunal community within 12 mo, complete after 18 mo. 

Experimental trawling for 1 day/mo (one and a half tows per unit of area) for 16 mo in area closed to fishing for >25 years; recovery monitored after 6, 12, and 18 mo. 
Page 114

Table 5.5. Effects of otter trawls on sand substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1 Ball et al. 2000 Irish Sea 35 m Muddy sand Lower number of infaunal and epifaunal species and 

individuals, and lower species diversity and richness, compared to wreck site. 

 Experimental trawling in a heavily 

fished fishing ground; unfished area near a shipwreck used as control. 

2 Bergman and van 

Santbrink 2000 

Southern North Sea 

(Dutch coast) 

<30-50 m Silty sand 

and sand 

High (20-50%) mortalities for six sedentary and/or immobile megafaunal (>1 cm) species, <20% for 10 others, from a single pass of the trawl; S effects on 11 of 54 occasions. 

 Experimental trawling (one- and-a-half 

tows per unit of area) in commercially trawled area; effects assessed after 24-48 hr. 

3 DeAlteris et al.

1999

Narragansett Bay, 

Rhode Island, USA 

7 m Sand No tracks found. Hand dug trenches 

not visible after 1-4 days. 

Diver observations. 

4 Drabsch et al. 2001 Gulf of St. Vincent, 

South Australia 

20 m Coarse sand 

with shells 

Trawl door tracks; smoothing of topographic features; removal of, and damage to epifauna; no S effects on total infaunal abundance; S reduction in density for one order of crustaceans 1 wk of trawling. 

 Experimental trawling (two tows per 

unit area) in area with no trawling for 15 yr; effects assessed after 1 wk (site one) and 3 mo (site two). 

5 Frid et al. 1999 Northeast England 

(North Sea) 

55 m Sand Total abundance of benthic macrofauna increased as 

phytoplankton abundance increased; no correlation with fishing effort. 

 Related changes in benthic fauna in a 

lightly trawled location to low, high, and moderate fishing activity, and to changes in phytoplankton production over 27 yr. 

6 Gibbs et al. 1980 Botany Bay, New 

South Wales, 

Australia 

Shallow 

estuary 

Sand with 0- 

30% silt-clay

Sediment plume; no consistent effects on benthic community diversity; very little disturbance of seafloor. 

 Sampling before, immediately after, and 

6 mo after 1 wk of experimental trawling in a fished location; control area located 200 km away. 

7 Gilkinson et al.

1998

Test tank to simulate 

Grand Banks of 

Newfoundland 

 Sand Trawl door created 5.5-cm berm adjacent to 2-cm 

furrow; bivalves displaced, but little damage. 

 Observed effects of commercial otter 

door model in test tank. 

8 Hall et al. 1993 North Sea 80 m Coarse sand Abundance of infauna related to changes in sediment 

type and organic content, not distance from shipwreck. 

 Sampled infauna at increasing distance 

from a shipwreck (proxy for increasing fishing effort). 

9 McConnaughey et 

al. 2000 

Eastern Bering Sea, 

Alaska 

44-52 m Sand with 

ripples 

Reduced abundance (S for sponges and anemones); more patchy distribution; S decrease in species diversity of sedentary epifauna; mixed responses of motile taxa and bivalves. 

 Compared abundance of epifauna caught 

in small-mesh trawl inside and outside an area closed to trawling for almost 40 yr. 
Page 115

Table 5.5 (cont.). Effects of otter trawls on sand substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

10 Moran and 

Stephenson 2000 

Northwest 

Australia 

50-55 

m 

Not given, 

presumed to 

be sand 

Single tow reduced density of macrobenthos (>20 cm) by 15%, 4 tows by 50%. 

 Video surveys before and after four 

experimental trawling events (one tow per unit area) at 2-day intervals in unexploited area. 

11 Sainsbury et al.

1997

Northwest 

Australia 

<200 

m 

Calcareous 

sands 

Decreased abundance of benthic organisms and fish associated with large epifauna; removal of attached epifauna (single tow removed 89% of sponges >15 cm). 

Increased catch rates of fish associated with large epifauna and small (<25 cm) benthos within 5 yr; recovery of large epifauna takes >5 yr. 

Compared historical survey data (before and after fishing started) to data collected in area that remained open to commercial trawlers and to area closed for 5 yr. 

12 Kenchington et

al. 2001 

Grand Banks, 

Newfoundland 

120-

146 m 

Fine to 

medium grain 

sand 

S short-term reductions in total abundance and abundance of 15 infaunal and epifaunal taxa (mostly polychaetes) in only 1 of 3 yr; no short-term effects on biomass or taxonomic diversity; no long-term effects. 

Benthic organisms that were reduced in abundance in 1994 had recovered a yr later. 

Experimental trawling (3-6 tows per unit of area) in closed area 1, 2, and 3 yrs after closure; lightly exploited for >10 yrs; effects evaluated within several hours or days after trawling and after 1 yr. 

13 Prena et al. 1999 Grand Banks, 

Newfoundland 

120-

146 m 

Fine to 

medium grain 

sand 

24% average decrease in epibenthic biomass; S reductions in total and mean individual epifaunal biomass, and biomass of five of nine dominant species; damage to echinoderms. 

 Experimental trawling (3-6 tows per unit of 

area) in closed area 1, 2 and 3 yr after closure, lightly exploited for >10 yr. 

14 Schwinghamer

et al. 1998 

Grand Banks, 

Newfoundland 

120-

146 m 

Fine and 

medium grain 

sand 

Tracks in sediment; increased bottom roughness; sediment resuspension and dispersal; smoothing of seafloor and removal of flocculated organic material; organisms and shells organized into linear features. 

Tracks last up to 1 yr; recovery of seafloor topography within 1 yr. 

Experimental trawling (3-6 tows per unit area) in closed area 1, 2 and 3 yr after closure, lightly exploited for >10 yr. 
Page 116

Table 5.6. Effects of otter trawls on gravel/rock substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1 Auster et

al. 1996 

Jeffreys 

Bank, Gulf 

of Maine 

94 m Gravel/boulder with 

thin mud veneer. 

Gravel base exposed; boulders moved; reduced abundance of erect sponges and associated epifaunal species; changes attributed to trawling. 

 Submersible and video observations in 

same location in 1987 and 1993. 

2 Freese et

al. 1999 

Gulf of 

Alaska 

206-

274 m 

93% pebble, 5% 

cobble, 2% boulder. 

Boulders displaced; groundgear left furrows 1-8 cm deep in less compact sediment; layer of silt removed in more compact sediment; S reductions in abundance of sponges, anemones, and sea whips; damage to sponges, sea whips and brittle stars. 

 Video observations from a submersible 

2-5 hr after single trawl tows in area exposed to little or no commercial trawling for about 20 yr. 

3 Dolah et al.

1987

Georgia, SE 

U.S. coast 

20 m Smooth rock with thin 

layer of sand and 

attached epifauna. 

Damage to sponges and corals, mostly to sponges; S reductions in density of undamaged barrel sponges in high-density transects; no S effects on densities of vase sponges, finger sponges, or stony corals. 

Full recovery of damaged organisms and density within 12 mo. 

Experimental study using diver counts of large sponges and corals before, immediately after, and 12 mo after, a single tow of a “roller” trawl in an unexploited area. 

Table 5.7. Effects of otter trawls on mixed substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1 DFO 1993 Bras d’Or 

Lakes, Nova 

Scotia, Canada 

10–

500 m 

Mud, sand, 

gravel, and 

boulders 

Trawl doors left parallel marks (furrows and berms), fainter marks from footgear, primarily in mud. 

 Sidescan sonar survey after area was 

closed to mobile gear for 1 yr. 

2 Engel and 

Kvitek 1998 

California, 

USA 

180 m Gravel, sand, 

silt, and clay 

S fewer rocks and biogenic mounds, S less flocculent material, and S more exposed sediment and shell fragments in HF area; lower densities of large epibenthic taxa in HF area (S for sea pens, starfish, anemones, and sea slugs); higher densities of nematodes, oligochaetes, brittle stars and one species of polychaete in HF area; no differences between areas for crustaceans, mollusks, or nemerteans. 

 Used a submersible and grab 

samples (3 yr) to compare lightly trawled and heavily trawled commercial fishing sites with same sediments and depth. 

3 Smith et al.

1985 

Long Island 

Sound, New 

York, USA 

Not 

given 

Sand and 

mud 

Tracks in sediment (<5 cm in sand, 5-15 cm in mud); attraction of predators; suspension of epibenthic organisms. 

Tracks "naturalized" by tidal currents. 

Video and diver observations. 
Page 117

Table 5.8. Effects of New Bedford-style scallop dredges on sand substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1 Auster et al. 1996 Stellwagen Bank, 

Gulf of Maine, 

USA 

20-55 

m 

Coarse sand Smoothing of sand ripples and low sand 

waves; dispersal of shell deposits in wave troughs. 

 Examined gear tracks in sidescan 

sonar images. 

2 Langton and Robinson 

1990

Fippennies 

Ledge, Gulf of 

Maine, USA 

80-100 

m 

Gravelly sand with 

some gravel, shell 

hash, and small 

rocks 

Coarser substrate; disruption of amphipod tube mats; piles of small rocks and scallop shells dropped from surface; S reductions in densities of tube dwelling polychaete and burrowing anemone. 

 Submersible observations made 1 yr 

apart, before and after commercial dredging of area. 

3 Watling et al. 2001 Damariscotta 

River, Maine, 

USA 

15 m Silty sand Loss of fine surficial sediments; lowered 

food quality of sediment; reduced abundance of some taxa; no changes in number of taxa; S reductions in total number of individuals 4 mo after dredging. 

No recovery of fine sediments, full recovery of benthic fauna and food value within 6 mo. 

Experimental study (23 tows in 1 day); effects on macrofauna (mostly infauna) evaluated 1 day and 4 and 6 mo after dredging in an unexploited area. 

Table 5.9. Effects of New Bedford-style scallop dredges on mixed substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1 Caddy 1968 Northumberland Strait, 

Gulf of St. Lawrence, 

Canada 

20 m Mud and sand Drag tracks (3 cm deep) produced by skids; smooth ridges between 

them produced by rings in drag belly; dislodged shells in dredge tracks. 

 Diver observations of physical 

effects of two tows. 

2 Caddy 1973 Chaleur Bay, Gulf of St. 

Lawrence, Canada 

40-50 

m 

Gravel over sand, 

with occasional 

boulders 

Suspended sediment; flat track, marks left by skids, rings, and tow bar; gravel fragments less frequent (many overturned); rocks dislodged or plowed along bottom. 

 Submersible observations of tow 

tracks made <1 hr after single dredge tows. 

3 Mayer et al.

1991

Coastal Gulf of Maine, 

USA 

8 m Mud, sand, and 

shell hash 

Lowered sediment surface by 2 cm, injected organic matter and finer sediment into lower 5-9 cm; increased mean grain size in upper 5 cm; disruption of surface diatom mat; increased microbial biomass at sediment surface. 

 Experimental study, compared 

dredged and undredged sites before and 1day after a single dredge tow. 
Page 118

Table 5.10. Effects of toothed scallop dredges on sand substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1,2 Black and 

Parry 1994,

1999

Port Phillip Bay, 

SE Australia 

(three sites) 

15 m Sand (7-

30% siltclay) 

Sediment plume; maximum depth of disturbance 4-6 cm into bottom; cutterbar trims off high regions of seafloor. 

Turbidity returned to normal storm levels within 9 min. 

Experimental dredging for 2-4 days (two to four tows per unit area) in three areas with no commercial dredging for 4 yrs. 

3,4 Currie and

Parry 1996,

1999b

Port Phillip Bay, 

SE Australia (St. 

Leonards site) 

15 m Fine/very 

fine sand 

Flattening of low-relief biogenic mounds; depressions filled in; parallel tracks produced by skids; S fewer species after 3 wks; 

most species 20-30% less abundant 3.5 mo after dredging; S reduced abundance of 6 of 10 most common infaunal species within first 3.5 mo (S increase for one species); no effect on total number of individuals; surface-dwelling organisms released into water column right away, burrowing organisms as dredging continued; increased abundance of more mobile, opportunistic species within first 3.5 mo. 

Mounds reformed after 6 mo; tracks visible after 1 mo, but not after 6 mo; most species recovered within 8 mo, but some had not after 14 mo. 

Experimental dredging for 3 days (2 tows per unit of area) in an area with no commercial dredging for 4 yr; recovery of infauna monitored at 5 intervals during 14 mo; seafloor changes at 8 days and at 6 and 11 mo. 

Port Phillip Bay, 

SE Australia 

(Dromana site) 

15 m Mediumfine sand Removal of small, parallel sand ripples; S reductions in abundance of three of ten most common infaunal species within 2 

days. 

Ripples reformed after 5 days following storm. 

Experimental dredging for 2 consecutive days (2 tows per unit of area) in an area with no commercial dredging for 4 yr; effects on infauna evaluated after 2 days, seafloor changes after 5 days. 

4 Currie and

Parry

1999b

Port Phillip Bay, 

SE Australia 

(Portarlington 

site) 

15 m Muddy sand 

with shell 

fragments 

Flattening of biogenic mounds; S reductions in abundance of 2 of 10 most common infaunal species within 1 day. 

Mounds reformed 7 months after dredging, but were still smaller than in undredged area. 

Experimental dredging for 4 days (four tows per unit area) in an area (Portarlington) with no commercial dredging for 4 yrs; effects on infauna evaluated after 1 day, seafloor changes after 7 mo. 

5 Butcher et al.

1981 

Jervis Bay, New 

South Wales, 

Australia 

>13 m Sand Sediment plume up to 5 m off bottom, flattening of sand ridges. Sediment plume settled out 

within 15 min. 

Diver observations. 

6 Eleftheriou

and

Robertson

1992

Firemore Bay, 

Loch Ewe, 

Scotland 

5 m Well-sorted 

sand 

Dredge eliminated natural bottom features; teeth created 3-4 cm deep furrows; no effect on sediment characteristics; damage or mortality of larger epifauna, razor clams, and sand lance, attraction of predators; increase in some species of small infaunal crustaceans; initial reduction in polychaetes followed by increase; no effect on taxa adapted to dynamic environment (e.g., 

amphipods, bivalves). 

Grooves and furrows no longer visible shortly after dredging, duration depended on wave and current action. 

Evaluation of incremental effects of dredging (25 tows in 1 wk) at a single site (no control). 

7 Thrush et al.

1995

Mercury Bay, 

New Zealand 

24 m Coarse sand Breaking down of surface sediment features; grooves 2-3 cm 

deep created by teeth; S declines in abundance of 6 of 13 most common taxa at unexploited site, and 4 of 13 most common taxa at exploited site; S reductions in total number of individuals and taxa at both sites. 

General recovery of macrobenthic abundance at previously exploited site after 3 mo, but not at unexploited site. 

Experimental dredging (5 parallel tows in 1 day) at a previously exploited and an unexploited site with different benthic communities; biological effects evaluated within 2 hr and 3 mo after dredging. 
Page 119

Table 5.11. Effects of toothed scallop dredges on biogenic substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications. 

Reference Location Depth Sediment Effects Recovery Approach

HallSpencer and

Moore

2000a

Clyde Sea, 

Scotland 

10-15 

m 

Live bottom 

(maerl) with 

some cobble 

and boulders 

Disturbance of seafloor to 10 cm; overturned boulders; suspended sediment; erasure of bottom features and burial of living maerl in dredge tracks; most megafauna in top 10 cm either caught in dredge or left damaged in dredge track (large, fragile organisms 

more vulnerable); rapid aggregation of predatory 

species in track. 

Dredge tracks remained visible for 0.5-2.5 yrs; some recovery rates of large epibenthic species variable, some recovering quickly, but others at unexploited site had not recovered 4 yr after dredging; macrobenthic community at previously exploited site recovered within 2 yr. 

Observations of the effects of single dredge tows at a previously dredged and undredged site; immediate effects and recovery (after 4 yr) evaluated by divers using video cameras. 

Table 5.12. Effects of toothed scallop dredges on mixed substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1 Bradshaw et

al. 2002 

Isle of Man, 

Irish Sea 

Not 

given 

Sand and gravel More vulnerable taxa less abundant in recent samples, less 

vulnerable taxa more abundant; faunal differences and proportion of species “lost” between time periods increased significantly as number of years since fishing began increased; no effect of increases in total effort; no clear evidence over all sites for reduced species diversity. 

 Recent benthic sample data collected at 7 

sites exposed to varying amounts of fishing effort compared with data collected 50-60 yr ago, when scallop fishing was very limited. 

2,3 Bradshaw et

al. 2000,

2001

Isle of Man, 

Irish Sea 

25-40 

m 

Gravel, sand, and 

mud 

6 mo of experimental dredging in closed area altered community structure, no trends in abundance of individual species; no S effects on number of species, but community heterogeneity was reduced; encrusting species were more abundant and upright species less abundant in dredged plots than in control plots after 3 yr. 

S increases in abundance of several epifaunal species in undredged portion of closed area 5-9 yr after closure. 

Continuous experimental dredging (10 tows every 2 mo for 3 yr) in an area closed to commercial fishing for 6 yr; semi-annual grab sampling inside and outside closed area, and biannual diver surveys of epibenthic animals in closed area. 

4 Caddy 1973 Chaleur Bay, 

Gulf of St. 

Lawrence, 

Canada 

40-50 

m 

Gravel over sand, 

with occasional 

cobble and 

boulders. 

Shallow, flat tracks; tooth marks in sand; boulders dislodged and small rocks “plowed” by dredge; spoil ridges at edges of track. 

 Submersible observations and photographs 

of tow tracks made <1 hr after dredging. 

5 DFO 1993 Bras d’Or 

Lakes, Nova 

Scotia, Canada 

10-

500 m 

Gravel and mud Furrows left by dredge teeth; berms at outer edges of 

dredge track. 

 Sidescan sonar survey 1 yr after area was 

closed to mobile gear. 

6 Kaiser, Hill

et al. 1996 

Irish Sea, 

southwest of 

Isle of Man 

Not 

given 

Not given, assume 

mixed substrates 

Reduced abundance of most large epibenthic species; same effects on community structure as beam trawls, but lower bycatch. 

 Experimental study of effects of dredging 

(10 tows) and beam trawling on large epifauna; sampling with small-mesh (40mm) beam trawl both before and 24 hr after fishing. 

7 Kaiser,

Ramsay et

al. 2000 

Irish Sea Not 

given 

Coarse sand and 

gravel 

S more epifaunal organisms in areas exposed to high fishing effort, no effects on infauna or on diversity or number of epifaunal species; shift from communities dominated by more larger-bodied to fewer smaller-bodied organisms. 

 Compared benthic communities in areas 

exposed to 10 yr of low and high fishing effort. 

8 Veale et al.

2000

Irish Sea 20-67 

m 

Coarse sand or 

gravel, often 

overlain with 

pebbles, cobbles 

and dead shell. 

S decreases in epibenthic species diversity and total number of species and individuals with increasing fishing effort; total abundance, biomass, and production and production of most taxa S decreased with increasing effort. 

 Compared dredge bycatch from fishing 

grounds exposed to varying amounts of fishing effort during previous 60 yr. 
Page 120

Table 5.13. Effects of other nonhydraulic dredges on biogenic substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1 Fonseca et al.

1984

Beaufort, North 

Carolina, USA 

Very shallow, 

subtidal 

Silty sand with 

eelgrass 

S reduction in number of eelgrass shoots and leaf biomass with increased dredging intensity at each of two sites, one hard bottom and one soft bottom. 

 Experimental study with lightweight toothless 

dredge; two levels of disturbance. 

2 Langan 1998 Piscataqua 

River, MaineNH, USA 

Not given Oyster bed No detectable differences in the number of 

benthic invertebrates, species richness, or diversity; turbidity of near-bottom water doubled 10 m behind dredge. 

Turbidity returned to normal 110 m behind dredge. 

One-time sampling of benthic invertebrates in dredged and undredged sides of the river; turbidity measured during a single dredge tow. 

3 Lenihan and 

Peterson 1998 

Neuse River, 

North Carolina, 

USA 

3 and 6 m Oyster reefs Dredging lowered mean height of 1 m reefs by 

~30%. 

 Experimental study where 4 of 8 oyster-shell reefs 

were dredged for 1 wk to remove all market-sized oysters; sampled 3 days before and 2 days after dredging.. 

4 Riemann and 

Hoffmann

1991

Limfjord, 

Denmark 

Mean depth 7 

m, maximum 

15 m 

Not given 

(presumed 

mussel bed) 

S increase in suspended particulate matter; S reduction in oxygen immediately after dredging, especially near the bottom. 

Turbidity returned to normal within 1 hr. 

Water column sampling of physical and chemical attributes with a 2-m mussel dredge before and after dredging (maximum 1 hr) at an experimental and a control site. 

Table 5.14. Effects of hydraulic clam dredges on mud substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) 

Reference Location Depth Sediment Effects Recovery Approach

Hall and 

Harding

1997

Auchencairn Bay, 

Solway Firth, 

Scotland 

Intertidal Mud Dredge tracks; S reductions in number of infaunal 

species and individuals persisted for 4 wk; 3 of 5 dominant species reduced in abundance throughout experiment (8 wk). 

Nearly complete recovery of infaunal community after 8 wk, but some effects remained; dredge tracks not seen after first day. 

Experimental study of the effects of single suction dredge passes in a commercially harvested area; recovery monitored 1, 4, and 8 

wk after dredging. 
Page 121

Table 5.15. Effects of hydraulic clam dredges on sand substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) 

No. Reference Location Depth Sediment Effects Recovery Approach

1 Hall et al.

(1990)

Loch 

Gairloch, 

Scotland 

7 m Fine sand Shallow trenches (25 cm deep) and large 

holes; sediment “almost fluidized”; median sediment grain size S higher in fished area; S reductions in numbers of infaunal organisms; no effect on abundance of individual species; some mortality (not assessed) of large polychaetes and crustaceans retained on conveyor belt or returned to sea surface. 

Complete recovery of physical features and benthic community after 40 days; filling of trenches and holes accelerated by winter storms. 

Experimental study in unexploited area to evaluate effects of simulated commercial escalator dredging activity; recovery evaluated after 40 days. 

2 Kaiser,

Edwards et

al. (1996b)

SE England Intertidal Muddy sand Resuspension and loss of fine sand from 

sediment surface; S reductions in total number of infaunal species and individuals. 

Complete recovery of sediments and benthic community within 7 mo. 

Experimental study; effects of suction dredging for cultivated clams evaluated after 3 hr and 7 mo. 

3 MacKenzie,

1982

East of Cape 

May, New 

Jersey, USA 

37 m Very fine to 

medium 

sand 

Resorting of sediments (coarser at bottom of dredge track); no effect on number of infaunal individuals or species, nor on species composition. 

 Comparison of actively fished, recently fished, and 

never fished areas on the continental shelf; dredging conducted with hydraulic cage dredges. 

4 Maier et al.

1995 

South 

Carolina, 

USA 

Tidal 

creeks 

Muddy sand Turbidity plumes; no S effects on abundance 

of dominant infaunal taxa or total number of individuals. 

Turbidity plumes persisted for a few hours. 

Before and after study of commercial escalator dredging effects in four tidal creeks. Turbidity monitored 2 wk before, during, and 2 wk after 

dredging at one location, and during and immediately after dredging at another. Infaunal samples collected 3 wk before and 2 wk after dredging in a creek that had been commercially dredged 5 yr prior to the study and in a creek that had never been dredged before. 

5 Medcof and 

Caddy 1971 

Southern 

Nova 

Scotia, 

Canada 

7-12 m Sand and 

sand-mud 

Smooth tracks with steep walls, 20 cm deep; sediment cloud. 

Sediment plume lasted 1 min; dredge tracks still clearly visible after 2-3 days. 

SCUBA and submersible observations of the effects of individual tows with a cage dredge. 

6 Meyer et al.

1981

Long Island, 

New York, 

USA 

11 m Fine to 

medium 

sand, 

covered by 

silt layer 

>20-cm-deep trench; mounds on either side of trench; silt cloud, attraction of predators. 

Trench nearly indistinct, and predator abundance normal, after 24 hr; silt settled in 4 min. 

SCUBA observations during and following a single tow with a cage dredge in a closed area; effects evaluated after 24 hr. 

7 Pranovi and 

Giovanardi

1994

Venice 

Lagoon, 

Adriatic 

Sea, Italy 

1.5-2 m Sand 8-10 cm deep trench; S decrease in total 

abundance, biomass, and diversity of benthic macrofauna in fishing ground; no S effects outside fishing ground. 

After 2 mo, dredge tracks still visible; densities (especially of small species and epibenthic species) in fishing ground recovered, biomass did not. 

Experimental dredging with a cage dredge (single tows) in previously dredged and undredged areas in coastal lagoon; recovery monitored every 3 wk for 2 mo. 

8 Tuck et al.

2000

Sound of 

Ronay, 

Outer 

Hebrides, 

Scotland 

2-5 m Medium to 

fine sand 

Steep-sided trenches (30 cm deep); sediments fluidized up to 30 cm; S decrease in number of infaunal species and individuals within a day of dredging; S decrease in proportion of polychaetes and S increase in proportion of amphipods 5 days after dredging; S increases in abundance of some species and S decreases in abundance of other species. 

Trenches no longer visible but sand still fluidized after 11 wk; species diversity and total abundance recovered within 5 days; proportions of polychaetes and amphipods, and abundances of individual species, returned to pre-dredge levels after 11 wk. 

Experimental dredging with cage dredge (individual tows at 6 sites) in area closed to commercial dredging, effects evaluated 1 day, 5 days, and 11 wk after dredging. 
Page 122

Table 5.16. Effects of hydraulic clam dredges on mixed substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) 

Reference Location Depth Sediment Effects Recovery Approach

Murawski and 

Serchuk 1989 

Mid-Atlantic 

Bight, USA 

Not 

given 

Sand, mud, and 

coarse gravel 

Trench cut; temporary increase in turbidity, disruption of benthic organisms in dredge path; attraction of predators. 

Trenches filled quickly in coarse gravel, but took several days in fine sediments. 

Submersible observations following hydraulic cage dredge tows. 

Table 5.17. Effects of hydraulic clam dredges on biogenic substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1 Godcharles 

1971 

Tampa Bay, 

Florida, USA 

Not 

given 

Open sand, 

sand with 

seagrass, and 

sand with algae 

Water jets penetrate to 45 cm, create trenches 15-45 cm deep; uprooted vegetation; decreased proportion of fine sediment in some dredge tracks. 

Trenches lasted longer (up to 86 days) in grass beds, filled in immediately in open sand; most sediments hardened within 1 mo, some spots still soft 500 days after dredging; sediment composition returned to normal after 1 yr, but seagrass still had not recovered; new algal growth after 86 days, complete after a year. 

SCUBA observations and sediment sampling before and after experimental escalator dredging in undisturbed sand, seagrass, and algae bottom habitats; recovery monitored for 16+ mo. 

2 Orth et al.

1998 

Chincoteague 

Bay, Virginia, 

USA 

Not 

given 

Seagrass beds Circular “scars” left by 

dredges; loss of grass and large holes in dredge track. 

No revegetation 3 yr after disturbance; recovery estimated to take at least 5 yr in lightly disturbed areas, longer in heavily disturbed areas. 

Field observations of commercial escalator dredging effects over a 3-yr period. 

Table 5.18. Effects of pots and traps on mixed substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) 

Reference Location Depth Sediment Effects Recovery Approach

Eno et al.

2001

Badentarpet Bay, 

west coast of 

Scotland 

Not 

given 

Soft mud Bending and smothering of sea pens underneath 

pots; uprooting of some sea pens when pots are dragged over bottom. 

Sea pens recover from effects of pot dragging within 24-72 hr, re-assume upright posture within 72-144 hr of pot removal, and re-root as long as “foot” remains in contact with bottom. 

Diver observations and experiments to assess effects on, and recovery of, sea pens following dragging, uprooting, and smothering by lobster pots left on bottom for 24 or 48 hr. 

Eno et al.

2001

Greenale Pt., 

Wales, and Lyme 

Bay, southwest 

England 

14-20 

m 

Varied – from 

bedrock to boulders to 

coarse sediment – and 

interspersed. 

Soft corals bent by pots, but spring back; pots leave tracks in bottom when hauled; increased abundance of 4 species of sponges, an ascidian, and a bryozoan in experimental plots after 4 wk, no changes in abundance of other epibenthic species. 

 Diver observations and experiments to 

assess effects of 4 wk of simulated commercial pot fishing on attached epifauna at two study sites. 
Page 123

Table 5.19. Effects of multiple gears on sand substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1 Almeida et

al. 2000 

Eastern 

Georges 

Bank, USA 

<50-

>90 m 

Sandy Microhabitat associated with two species of sponges more abundant inside 

closed area; no S differences for six other microhabitat types. 

 Analysis of still photos and video imagery 

inside and outside area closed to trawls, dredges, longlines, and gill nets 4.5 yr after it was closed. 

2 Kaiser,

Spencer et

al. 2000 

South 

Devon 

coast, 

England 

15-70 

m 

Fine, 

medium, and 

coarse sand 

No S effect of high fishing effort on numbers of infaunal or epifaunal species or individuals; in high-effort areas there were: 1) a lower reduced abundance of larger, less mobile, and emergent epifauna; 2) a higher abundance of more epifauna; and 3) fewer high-biomass species of epifauna and infauna; infauna in deeper coarse-medium sand habitat most affected by fishing. 

 Compared benthic communities in areas of 

high, medium, and low fishing effort by fixed and mobile gears; each area with three sites (shallow, fine sand, deep medium sand, and deep coarse-medium sand). 

Table 5.20. Effects of multiple gears on gravel/rock substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach

1,2 Collie et al.

1997, 2000

Northern edge, 

eastern Georges 

Bank, U.S. and 

Canada 

42-90 

m 

Pebble-cobble 

“pavement” with 

some overlying 

sand 

S higher total densities, biomass, and species diversity in undisturbed sites, but also in deeper water (i.e., effects of fishing could not be distinguished from depth effects); 6 species abundant at U sites, rare or absent at D sites; percent cover of tube-dwelling polychaetes, hydroids, and bryozoans S higher in deepwater, but no disturbance effect. 

 Benthic sampling, video, and still 

photos in 2 shallow (42-47 m) and 4 deep (80-90 m) sites disturbed (D) and undisturbed (U) by trawls and scallop dredges. 
Page 124

Table 5.21. Effects of multiple gears on mixed substrate habitat: summary of published studies. (S = statistically significant; citations in bold print are peer-reviewed publications.) No. Reference Location Depth Sediment Effects Recovery Approach 

1 Auster et al. 1996 Coastal Gulf of 

Maine, USA 

30-40 

m 

Sand-shell S more sea cucumbers and bottom depressions inside 

closed area. 

 ROV and video observations inside and outside an area 

closed to mobile gear for 10 yr. 

1 Auster et al. 1996 Coastal Gulf of 

Maine, USA 

30-40 

m 

Cobble-shell S more emergent epifauna inside closed area. ROV and video observations inside and outside an area 

closed to mobile gear for 10 yr. 

1 Auster et al. 1996 Stellwagen 

Bank, Gulf of 

Maine, USA 

20-55 

m 

Sand with 

gravel and 

shell 

Disturbed sand ripples and sand waves; dispersed shell deposits; absence of epifauna and reduced microalgal cover in trawl and dredge tracks. 

 Sidescan sonar survey and ROV observations. 

2,3,4 Reise 1982;

Riesen and Reise

1982; Reise and 

Schubert 1987 

Wadden Sea, 

The Netherlands 

<23 m Mud, coarse 

sand, and 

some pebbles 

Loss of oyster and Sabellaria reefs; decrease in 

abundance of 28 species (mollusks and amphipods); 23 “new” species (many of them polychaetes). 

 Compared benthic surveys conducted during time period 

when oysters were overexploited and trawl fishery developed on Sabellaria reefs (1869-1986). 

5 Thrush et al. 1998 Hauraki Gulf, 

New Zealand 

17-35 

m 

Mud and 

sand 

S reductions in density of large epifauna, echinoderms, and long-lived surface dwellers; S increases in density of small, opportunistic species; some predictions contraindicated by results; 15-20% variability in macrofaunal community composition attributed to fishing pressure. 

 Tested 10 predictions of the effects of increasing fishing 

intensity on benthic community structure by comparing samples and video images from 18 stations exposed to varying degrees of commercial fishing pressure by bottom trawls, Danish seines, and scallop dredges. 

6 Valentine and 

Lough 1991 

Eastern Georges 

Bank 

 Sand and 

gravel 

Trawl and dredge tracks in sediments; sparse epifauna, gravel mounds, and smoother bottom in disturbed areas. 

 Sidescan sonar and submersible observations of area 

presumed to be disturbed by trawls and scallop dredges. 
Page 125

6. VULNERABILITY OF ESSENTIAL FISH HABITAT

TO BOTTOM-TENDING FISHING GEARS

INFORMATION NEEDS AND SOURCES

This section evaluates potential adverse effects of

bottom-tending fishing gears on benthic EFH in the

Northeast Region. These gears are regulated by the MSA

and the EFH final rule, 50 CFR 600.815(a)(2)(i). The EFH

final rule recommends that the evaluation consider the

effects of each fishing activity on each type of habitat

found within the EFH for any affected species and life

stage. The EFH rule further recommends that the following

information be reviewed in making an evaluation: 1)

intensity, extent, and frequency of any adverse effects on

EFH; 2) the types of habitat within EFH that may be

adversely affected; 3) habitat functions that may be

disturbed; and 4) conclusions regarding whether and how

each fishing activity adversely affects EFH.

The EFH final rule requires that EFH designations be

based on the best available information. This information

may fall into four categories that range from the least

specific (Level 1) to the most specific (Level 4). These

categories are defined as follows:

Level 1: Presence/absence data are available to describe

the distribution of a species (or life history

stage) in relation to potential habitats for

portions of its range.

Level 2: Quantitative data (i.e., density or relative

abundance) are available for the habitats

occupied by a species or life history stage.

Level 3: Data are available on habitat-related growth,

reproduction, and/or survival by life history

stage.

Level 4: Data are available that directly relate the

production rates of a species or life history stage

to habitat type, quantity, and location.

Existing EFH designations in the Northeast Region are

based primarily on Level 2 information. This level of

information is inadequate for making definitive determinations of the consequences of fishing-related habitat

alterations on EFH for any species or life stage in the region

because the habitat alterations caused by fishing cannot

be linked to any known effect on species productivity.

Therefore, this section of the document qualitatively

evaluates the vulnerability of benthic EFH for each species

and life history stage in the region to the effects of bottomtending fishing gear. Vulnerability is defined as the

likelihood that the functional value of benthic EFH would

be adversely affected by fishing. Further, given the limited

nature of the information available for this qualitative

evaluation, emphasis was placed on the identification of

potential adverse effects of fishing on benthic EFH.

Information used to perform these evaluations

included: 1) the EFH designations adopted by the MidAtlantic, New England, and South Atlantic Fishery

Management Councils; 2) the results of a Fishing Gear

Effects Workshop convened in October 2001 (NREFHSC

2002); 3) the information provided in this document,

including the results of existing scientific studies, and the

geographic distribution of fishing gear use in the Northeast

Region; and 4) the habitats utilized by each species and life

stage as indicated in their EFH designations and as

supplemented by other references. In most cases, habitat

utilization was determined from the information provided in

the EFH Source Documents (NOAA Technical Memorandum NMFS-NE Issues 122-152, 163, and 173-179), with

additional information from Collette and Klein-MacPhee

(2002).

EVALUATION METHODS AND RESULTS

 Vulnerability of EFH to bottom-tending fishing gear

was ranked as none, low, moderate, or high, based on a

matrix analysis of three primary components: 1) benthic life

stages of FMP-regulated species; 2) habitat function and

sensitivity; and 3) gear usage. The matrix analysis initially

ranked each habitat for its susceptibility to disturbance and

each gear for its potential adverse effects, and then

subsequently combined those two rankings with available

information on the habitat usage by species/life stages and

the distribution of gear usage, in order to obtain the EFH

vulnerability rankings.

These evaluations are summarized in Table 6.1. Note

in Table 6.1 that: 1) species and life stages for which EFH

vulnerability was “not applicable” are not included; and 2)

pots, traps, sink gill nets, and bottom longlines -- to which

the EFH of all species and life stages showed “low”

vulnerability -- are also not included.

The rationale for these evaluations is outlined by

species in Tables 6.2-6.45, and was based on the authors’

following three assumptions. First, the habitat’s value to

each species and life stage was characterized to the extent

possible based on its function in providing shelter, food,

and/or the right conditions for reproduction. For example,

if the habitat provided shelter from predators for juvenile or

other life stages, gear effects that could reduce shelter were

of greater concern than other effects. Second, in cases

where a food source was closely associated with the

benthos (e.g., infauna), the ability of a species to use

alternative food sources (e.g., generalist versus specialist

species) was evaluated. Third, since benthic prey

populations may also be adversely affected by fishing,
Page 126

gear effects that could reduce the availability of prey for

bottom-feeding species or life stages were of greater

concern than if the species or life stages were piscivorous.

The information in Tables 6.2-6.45 includes for each

life stage the geographical extent of EFH, its depth range,

its seasonal occurrence, and a brief EFH description that

includes -- for benthic life stages -- substrate characteristics. The information presented in columns 2-5 of these

tables is derived from EFH text descriptions and maps that

originally appeared in the NEFMC Omnibus EFH

Amendment (NEFMC 1998) and several FMPs prepared by

the NEFMC and MAFMC. Additional information, where

available, is provided at the bottom of each table to explain

the rationale that was used in making the gear-specific EFH

vulnerability rankings. EFH descriptions of depth,

seasonal occurrence, and habitats (columns 3-5 in Tables

6.2-6.45) are not always consistent among life stages of an

individual species. Spawning American plaice adults, for

example, are described as occurring from March through

June, but their eggs are described as occurring from

December through June on Georges Bank (Table 6.2). In

addition, the information in columns 3-5 in some cases does

not completely agree with the information provided in the

rationale.

The rest of this section details the methods that were

used to perform the evaluations and assign the rankings.

Life Stages

Five life stages were evaluated: eggs, larvae,

juveniles, adults, and spawning adults. Adult and

spawning adult life stages were in most cases combined for

evaluation purposes due to the difficulty in distinguishing

between the two. In some cases (e.g., pelagic life stages

that are not vulnerable to bottom-tending fishing gear

effects), a vulnerability ranking was not applicable.

Habitat Scoring and Ranking

Habitat rank was determined from four criteria that

were qualitatively evaluated for each life stage based on

existing information. Each evaluation resulted in a score

based on predefined scoring criteria.

The first three criteria were related to habitat function,

and included shelter, food, and reproduction. The fourth

criterion was habitat sensitivity. Scoring of these criteria

was determined as follows:

Shelter (scored from 0 to 2): If the life stage is not

dependent on bottom habitat to provide shelter, then it was

scored a 0. Almost every life stage evaluated has some

dependence on the bottom for shelter, so, with the

exception of a few egg stages, 0 was seldom selected. If the

life stage has some dependence on unstructured or

noncomplex habitat for shelter, then it was scored a 1. For

example, flatfishes that rely primarily on cryptic coloration

for predator avoidance, or on sand waves for refuge from

bottom currents, were scored a 1. If the life stage has a

strong dependence on complex habitats for shelter, then it

was scored a 2. For example, juvenile Atlantic cod and

haddock, which rely heavily on structure or complex

habitat for predator avoidance, were scored a 2.

Food (scored from 0 to 2): If the life stage is not dependent

on benthic prey, then it was scored a 0. For example, eggs

were always scored a 0, as were life stages that fed

exclusively on plankton. If the life stage utilizes benthic

prey for part of its diet, but is not exclusively a benthic

feeder, then it was scored a 1. For example, species feeding

opportunistically on crabs as well as squid or fish were

scored a 1. If the life stage feeds exclusively on benthic

organisms and cannot change its mode of feeding, then it

was scored a 2.

Reproduction (scored from 0 to 1): Limited knowledge of

spawning behavior and habitat usage for many species

made this the most difficult category to assess. In the

opinion of the authors, the available information was

insufficient to evaluate this criterion beyond a simple yes

or no, resulting in a scoring of 0 or 1 for this factor. While

this two-level scoring instead of three-level scoring may

have unavoidably undervalued reproduction for some

species in the overall scoring, it was decided that this was

better than attempting to make finer distinctions that were

unsupportable based on available evidence.

A score of 0 was selected for nonreproductive life

stages (larvae and juveniles), and for species that are

known to spawn in the water column and have only pelagic

early life stages. A score of 1 was selected for species

where a known association with the bottom exists for one

or more aspects of the reproductive cycle.

Habitat Sensitivity (scored from 0 to 2): This criterion

does not evaluate the function of the habitat, but instead

accounts for its overall relative sensitivity to disturbance.

The type of benthic habitat (defined primarily in terms of

depth, energy regime, and substrate) inhabited by each

species and life stage was based primarily upon its EFH

designation.

If a habitat was not considered sensitive to

disturbance, then it was scored a 0. However, a score of 0

was not used for any benthic habitat type. If the habitat

was considered to have a low sensitivity to disturbance,

then it was scored a 1. For example, habitats that are highenergy environments without structural complexity, or that

have rapid recovery rates, were scored a 1 (e.g., highenergy sand environments). If the habitat type was

considered highly sensitive to disturbance, then it was

scored a 2. For example, habitats that are structurally

complex (e.g., those supporting epibenthic communities or
Page 127

those with boulder piles), or that have very slow recovery

rates (e.g., low-energy deepwater environments), were

scored a 2.

These scores were based on existing conceptual

models that show a direct relationship between higher

structural complexity of the habitat, longer recovery time,

and increased vulnerability to disturbance (NREFHSC

2002; NRC 2002).

Habitat rank was defined as the sum of the scores for

the four habitat criteria (shelter + food + reproduction +

habitat sensitivity). Another way to characterize the

habitat rank is the relative vulnerability of the habitat to

non-natural physical disturbance. The habitat ranks

ranged from 0 to 7, with 7 being the most vulnerable.

Gear Types, Scoring, and Ranking

Five fishing gear classifications were evaluated: otter

trawls, New Bedford-style scallop dredges, hydraulic clam

dredges, pots and traps, and sink gill nets and bottom long

lines. The pot/trap and net/line gear types were considered

to have the least effect of the five gear types evaluated.

The panel of experts that met in October 2001 ranked their

concerns over effects from fixed bottom-tending gear well

below their concerns over the effects from mobile bottomtending gear (NREFHSC 2002). Based on the limited

information available (Eno et al. 2001; NREFHSC 2002), the

vulnerability of all EFH for all benthic species and life

stages to pot and trap usage was considered to be low.

Similarly, there is little scientific information that evaluates

the effects of sink gill nets and bottom longlines on benthic

marine habitats, and none evaluates these effects in the

Northeast Region. Consequently, like pots and traps, the

vulnerability of all EFH for all benthic species and life

stages to sink gill net and bottom longline usage was

considered to be low. These rankings should be revisited

as more information on gear effects becomes available.

The greatest concern is for the vulnerability of benthic

EFH to mobile bottom-tending gears (see Chapters 3 and 4).

In the northeastern United States, these gear types include

various types of bottom otter trawls, New Bedford-style

scallop dredges, and hydraulic clam dredges. Otter trawls

are responsible for most of the fisheries landings

throughout the Northeast Region, and are used in a variety

of substrates, depths, and areas. Scallop dredges are used

in sand and gravel substrates. Hydraulic clam dredges are

used only in sand, shell, and small gravel within welldefined areas .

Rather than rate the relative effects of these three gear

types on EFH, they were treated as having similar effects.

The criterion for each gear type was based on the spatial

distribution of gear use (scored from 0 to 2) in areas

designated as EFH for a given species and life stage. If the

gear is not currently used within the EFH area, then it was

scored a 0. If the gear is currently used in only a small

portion of the EFH area, then it was scored a 1. If the gear is

currently used in more than a small portion of the EFH area,

then it was scored a 2.

The spatial distribution of fishing activity for each

gear was determined from reports of the number of days

absent from port, or the days fishing, for individual TMSs

of latitude and longitude during 1995-2001 (see Chapter 4).

Maps of TMSs designated as EFH are available in NEFMC

(1998) and in various fishery management plans developed

by the Mid-Atlantic and South Atlantic Fishery Management Councils, and have not been reproduced for this

document.

The gear rank assesses the overall effect on EFH from

fishing with bottom trawls, scallop dredges, and clam

dredges. This gear rank was defined as the product of the

habitat rank and the gear distribution score. This

relationship was chosen in order to ensure that the EFH

vulnerability from gears not used in a particular habitat (i.e.,

gear distribution = 0) would be 0, or, no effect.

EFH Vulnerability Ranking

Based on natural breaks in the frequency distribution

of the gear rankings, the following vulnerability categories

were defined:

0 = no vulnerability to the gear. This score could only be

attained if the gear was not used in the habitat (gear

distribution = 0).

1-6 = low vulnerability to the gear. This score generally

occurred where the gear has minimal overlap with EFH

(gear distribution = 1) and habitat rank was <7.

Additionally, low vulnerability scores occurred in habitats

with high gear overlap (gear distribution = 2) and habitat

rank was 3.

7-9 = moderate vulnerability to the gear. This score

typically occurred where gear overlap with EFH was high

(gear distribution = 2) and habitat rank was 4, or, overlap

with EFH was low (gear distribution = 1) and habitat rank

was 7.

10-14 = high vulnerability to the gear. This score occurred

only if the gear overlap with EFH was high (gear

distribution = 2) and the habitat rank was 5.
Page 128

Table 6.1. EFH vulnerability matrix analysis for benthic life stages of federally managed fish and invertebrate species in the Northeast U.S. Shelf Ecosystem

Habitat Criteria Scores Gear Distribution Scoresg Gear Rankh EFH Vulnerability Categoryi

Species and Species

Groupsa Shelterb Foodc Repro- ductiond Habitat Sensitivitye Habitat Rankf Otter Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

American Plaice (A) 1 2 1 1 5 2 2 0 10 10 0 High High None American Plaice (J) 1 2 0 1 4 2 2 0 8 8 0 Mod Mod None Atlantic Cod (A) 1 1 0 2 4 2 2 1 8 8 4 Mod Mod Low Atlantic Cod (J) 2 1 0 2 5 2 2 0 10 10 0 High High None Atlantic Halibut (A) 1 1 1 1 4 2 2 0 8 8 0 Mod Mod None Atlantic Halibut (J) 1 2 0 1 4 2 2 0 8 8 0 Mod Mod None Atlantic Herring (E) 0 0 1 1 2 2 2 0 4 4 0 Low Low None Atlantic Herring (SA) 0 0 1 1 2 2 2 0 4 4 0 Low Low None Atlantic Surfclam (A) 1 0 1 1 3 2 2 2 6 6 6 Low Low Low Atlantic Surfclam (J) 1 0 0 1 2 2 2 2 4 4 4 Low Low Low Barndoor Skate (A) 1 1 1 1 4 2 2 1 8 8 4 Mod Mod Low Barndoor Skate (J) 1 2 0 1 4 2 2 1 8 8 4 Mod Mod Low Black Sea Bass (A) 2 1 0 2 5 2 2 2 10 10 10 High High High Black Sea Bass (J) 2 1 0 2 5 2 2 2 10 10 10 High High High Clearnose Skate (A) 1 1 1 1 4 2 2 2 8 8 8 Mod Mod Mod Clearnose Skate (J) 1 2 0 1 4 2 2 2 8 8 8 Mod Mod Mod Golden Deepsea Crab (J,A) 1 1 1 2 5 1 0 0 5 0 0 Low None None Goosefish (A) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Goosefish (J) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Haddock (A) 1 2 0 2 5 2 2 1 10 10 5 High High Low Haddock (J) 2 2 0 2 6 2 2 1 12 12 6 High High Low Little Skate (A) 1 1 1 1 4 2 2 2 8 8 8 Mod Mod Mod Little Skate (E) 0 0 1 1 2 2 2 2 4 4 4 Low Low Low Little Skate (J) 1 2 0 1 4 2 2 2 8 8 8 Mod Mod Mod Ocean Pout (A) 2 2 1 2 7 2 2 2 14 14 14 High High High Ocean Pout (E) 2 0 1 2 5 2 2 2 10 10 10 High High High Ocean Pout (J) 2 2 0 2 6 2 2 2 12 12 12 High High High Ocean Quahog (A) 1 0 1 1 3 2 2 2 6 6 6 Low Low Low Ocean Quahog (J) 1 0 0 1 2 2 2 2 4 4 4 Low Low Low Offshore Hake (A) 1 1 0 1 3 2 1 0 6 3 0 Low Low None Offshore Hake (J) 1 1 0 1 3 2 1 0 6 3 0 Low Low None Pollock (A) 1 1 1 1 4 2 2 1 8 8 4 Mod Mod Low Pollock (J) 1 1 0 1 3 2 2 1 6 6 3 Low Low Low Red Deepsea Crab (A) 1 1 1 2 5 1 0 0 5 0 0 Low None None Red Deepsea Crab (J) 1 1 0 2 4 1 0 0 4 0 0 Low None None Red Drum (A) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low 
Page 129

Table 6.1. EFH vulnerability matrix analysis for benthic life stages of federally managed fish and invertebrate species in the Northeast U.S. Shelf Ecosystem

Habitat Criteria Scores Gear Distribution Scoresg Gear Rankh EFH Vulnerability Categoryi

Species and Species

Groupsa Shelterb Foodc Repro- ductiond Habitat Sensitivitye Habitat Rankf Otter Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Red Drum (J) 2 1 0 2 5 1 0 0 5 0 0 Low None None Red Hake (A) 1 2 0 1 4 2 2 1 8 8 4 Mod Mod Low Red Hake (J) 2 2 0 2 6 2 2 2 12 12 12 High High High Redfish (A) 1 1 0 2 4 2 2 0 8 8 0 Mod Mod None Redfish (J) 2 1 0 2 5 2 2 0 10 10 0 High High None Rosette Skate (A) 1 1 1 1 4 2 2 2 8 8 8 Mod Mod Mod Rosette Skate (J) 1 2 0 1 4 2 2 2 8 8 8 Mod Mod Mod Scup (A) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Scup (J) 1 2 0 1 4 2 2 2 8 8 8 Mod Mod Mod Sea Scallops (A) 1 0 1 1 3 2 2 2 6 6 6 Low Low Low Sea Scallops (J) 1 0 0 1 2 2 2 2 8 8 8 Low Low Low Silver Hake (A) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Silver Hake (J) 1 1 0 2 4 2 2 2 8 8 8 Mod Mod Mod Smooth Skate (A) 1 2 1 1 5 2 2 0 10 10 0 High High None Smooth Skate (J) 1 2 0 1 4 2 2 0 8 8 0 Mod Mod None Spiny Dogfish (A) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Spiny Dogfish (J) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Summer Flounder (A) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Summer Flounder (J) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Thorny Skate (A) 1 1 1 1 4 2 2 0 8 8 0 Mod Mod None Thorny Skate (J) 1 2 0 1 4 2 2 0 8 8 0 Mod Mod None Tilefish (A) 2 2 0 1 5 2 1 0 10 5 0 High Low None Tilefish (J) 2 2 0 1 5 2 1 0 10 5 0 High Low None White Hake (A) 1 1 0 1 3 2 2 0 6 6 0 Low Low None White Hake (J) 1 2 0 1 4 2 2 0 8 8 0 Mod Mod None Windowpane Flounder (A) 1 0 0 1 2 2 2 2 4 4 4 Low Low Low Windowpane Flounder (J) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Winter Flounder (A) 1 1 1 1 4 2 2 2 8 8 8 Mod Mod Mod Winter Flounder (E) 0 0 1 1 2 2 2 2 4 4 4 Low Low Low Winter Flounder (J) 1 1 0 1 3 2 2 2 6 6 6 Low Low Low Winter Skate (J) 1 2 0 1 4 2 2 2 8 8 8 Mod Mod Mod Winter Skate (A) 1 1 1 1 4 2 2 2 8 8 8 Mod Mod Mod Witch Flounder (A) 1 2 0 1 4 2 1 1 8 4 4 Mod Low Low Witch Flounder (J) 1 2 0 1 4 2 1 0 8 4 0 Mod Low None Yellowtail Flounder (A) 1 2 0 1 4 2 2 2 8 8 8 Mod Mod Mod Yellowtail Flounder (J) 1 2 0 1 4 2 2 2 8 8 8 Mod Mod Mod 
Page 130

Table 6.1. EFH vulnerability matrix analysis for benthic life stages of federally managed fish and invertebrate species in the Northeast U.S. Shelf Ecosystem

Habitat Criteria Scores Gear Distribution Scoresg Gear Rankh EFH Vulnerability Categoryi

Species and Species

Groupsa Shelterb Foodc Repro- ductiond Habitat Sensitivitye Habitat Rankf Otter Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

a Life Stages: (E) = egg, (J) = juvenile, (A) = adult, and (SA) = spawning adult. b Shelter Scores: 0 = no dependence; 1 = lower dependence, not reliant on complex structure; and 2 = strong dependence, reliant on complex structure. 

c Food Scores: 0 = no dependence on benthic prey; 1 = includes benthic prey; and 2 = relies exclusively on benthic prey. d Reproduction Scores: 0 = no dependence (e.g., spawns in water column, or life stage not reproductive); and 1 = dependence (e.g., spawns on or over bottom). 

e Habitat Sensitivity Scores: 0 = not sensitive; 1 = low sensitivity (i.e., no habitat structural/complexity issues, and rapid recovery rates) such as high-energy sand habitats; and 2 = high sensitivity (i.e.,

 habitat structural/complexity issues, and slow recovery rates) such as deepwater/low energy habitats. f Habitat Rank: = shelter score + food score + reproduction score + habitat sensitivity score. g Gear Distribution Scores: 0 = gear not utilized in this habitat; 1 = gear operates in a small portion of this habitat; and 2 = gear operates in much of this habitat. h Gear Rank (i.e., overall effect on EFH of this particular gear) = habitat rank x gear distribution score. 

i EFH Vulnerability Category was assigned from gear ranks as follows: 0 = none, 1-6 = low vulnerability, 7-9 = moderate vulnerability, 10-14 = high vulnerability. 
Page 131

Table 6.2. American plaice EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge 

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GOM, GB, and estuaries from Passamaquoddy Bay to Saco Bay, and from Massachusetts Bay to Cape Cod Bay

30-90 

All year in GOM, December to June on GB; peaks in April and May for both areas 

Surface waters NA NA NA NA NA 

Larvae 

GOM, GB, SNE, and estuaries from Passamaquoddy Bay to Saco Bay, and from Massachusetts Bay to Cape Cod Bay 

30-130 Between January and August, with peaks in April and May Surface waters NA NA NA NA NA 

Juveniles 

GOM and estuaries from Passamaquoddy Bay to Saco Bay, and from Massachusetts Bay to Cape Cod Bay 

45-150 

Bottom habitats with finegrained sediments or a substrate of sand or gravel 

M M 0 L L 

Adults 

GOM, GB, and estuaries from Passamaquoddy Bay to Saco Bay, and from Massachusetts Bay to Cape Cod Bay 

45-175 

Bottom habitats with finegrained sediments or a substrate of sand or gravel 

H H 0 L L 

Spawning adults 

GOM, GB, and estuaries from Passamaquoddy Bay to Saco Bay, and from Massachusetts Bay to Cape Cod Bay 

<90 March through June Bottom habitats of all substrate types H H 0 L L 

Rationale: American plaice (Hippoglossoides platessoides) juveniles, adults, and spawning adults are concentrated in the GOM, where they occupy a variety of habitat types with substrates of gravel or fine-grained sediments including sand. Plaice avoid rocky and hard-bottom areas and prefer fine, sticky but gritty sand mixtures and mud, as well as oozy mud in deep basins (Klein-MacPhee 2002d). Plaice have been caught a considerable distance off the bottom, and move off the bottom at night (Klein-MacPhee 2002d). They feed primarily on epibenthic invertebrates (mostly echinoderms and amphipods), so there is a potential that prey resources may be adversely affected by otter trawls and scallop dredges, particularly in areas of lower energy and expected slower habitat recovery. EFH vulnerability to these gears was rated as high for adults and moderate for juveniles primarily because spawning occurs on the bottom. Since hydraulic clam dredges do not typically operate in the GOM, vulnerability for this gear was rated as none. 

a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 132

Table 6.3. Atlantic cod EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GOM, GB, eastern portion of continental shelf off SNE, and following estuaries: Englishman/ Machias Bay to Blue Hill Bay, Sheepscot R., Casco Bay, Saco Bay, Great Bay, Massachusetts Bay, Boston Harbor, Cape Cod Bay, and Buzzards Bay 

<110 

Begins in fall, peaks in winter and spring 

Surface waters NA NA NA NA NA 

Larvae 

GOM, GB, eastern portion of continental shelf off SNE and following estuaries: Passamaquoddy Bay to Penobscot Bay, Sheepscot R., Casco Bay, Saco Bay, Great Bay, Massachusetts Bay, Boston Harbor, Cape Cod Bay, and Buzzards Bay 

30-70 Spring Pelagic waters NA NA NA NA NA 

Juveniles 

GOM, GB, eastern portion of continental shelf off SNE and following estuaries: Passamaquoddy Bay to Saco Bay, Massachusetts Bay, Boston Harbor, Cape Cod Bay, and Buzzards Bay 

25-75 

Bottom habitats with a substrate of cobble or gravel 

H H 0 L L 

Adults 

GOM, GB, SNE, middle Atlantic south to Delaware Bay and following estuaries: Passamaquoddy Bay to Saco Bay, Massachusetts Bay, Boston Harbor, Cape Cod Bay, and Buzzards Bay 

10-150 

Bottom habitats with a substrate of rocks, pebbles, or gravel 

M M L L L 

Spawning adults 

GOM, GB, SNE, middle Atlantic south to Delaware Bay and following estuaries, Englishman/ Machias Bay to Blue Hill Bay; Sheepscot R., Massachusetts Bay, Boston Harbor, and Cape Cod Bay 

10-150 

Spawn during fall, winter, and early spring 

Bottom habitats with a substrate of smooth sand, rocks, pebbles, or gravel 

M M L L L 

Rationale: Atlantic cod (Gadus morhua) are distributed regionally from Greenland to Cape Hatteras , from nearshore to depths >400 m. In U.S. waters, they are concentrated on GB and in the GOM, on rough bottom from 10-150 m (Fahay et al. 1999; Klein-MacPhee 2002a). Eggs and larvae are pelagic, so EFH vulnerability is not applicable. Juvenile cod are found mostly in nearshore shoal waters or on offshore banks. Cobble is preferred over finer grained sediments, and this life stage appears to use benthic structure and cryptic coloration to escape predation (Fahay et al. 1999). Juvenile cod may benefit, perhaps strongly, from physical and biological complexity (Lindholm et al. (2001); see discussion in Chapter 2 of this document). Otter trawls and scallop dredges have been shown to reduce habitat complexity (see Chapter 5), therefore EFH vulnerability to these gear types was rated as high since the gear may affect the functional value of EFH for this life stage. Vulnerability to clam dredges was rated as none since this gear is not operated in juvenile cod EFH (see Chapter 4). Adults and spawning adults occupy a variety of hard-bottom habitat types, including rock, pebbles, and gravel, and tend to avoid finer sediments. Cod eat a wide variety of prey, including fish, decapod crustaceans, amphipods, and polychaetes (Fahay et al. 1999). Although adult cod are primarily found on rough bottom, the scientific literature does not indicate that this habitat type serves the same function as it does for juvenile cod. Based on the variable diet and lack of evidence for direct functional value of benthic habitat, EFH vulnerability to otter trawls and scallop dredges was rated as moderate. Adult cod may use areas where clam dredges operate, such as the nearshore waters of New Jersey, on a seasonal basis. Clam dredges operate only in sand (NREFHSC 2002), and the recovery of benthic communities from the effects of clam dredging in nearshore, sandy habitats is rapid (Table 5.15). Clam beds are not chronically disturbed by dredging since the population of clams, which are benthic infauna, must recover before fishing is again profitable (NREFHSC 2002). Based on this information and the rationale described for otter trawls and scallop dredges, habitat vulnerability for hydraulic clam dredges was rated as low. EFH vulnerability for adults applies to spawning adults as well.a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 133

Table 6.4. Atlantic halibut EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs GOM, GB 

Between late fall and early spring, peaks in November and December 

Pelagic waters to the seafloor 0 0 0 0 0 

Larvae GOM, GB Surface waters NA NA NA NA NA Juveniles GOM, GB 20-60 Bottom habitats with a substrate of sand, gravel, or clay M M 0 L L Adults GOM, GB 100-700 Bottom habitats with a substrate of sand, gravel, or clay M M 0 L L Spawning adults GOM, GB <700 

Between late fall and early spring, peaks in November and December 

Bottom habitats with a substrate of soft mud, clay, sand, or gravel; rough or rocky bottom locations along slopes of the outer banks 

M M 0 L L 

Rationale: Atlantic halibut (Hippoglossus hippoglossus) are found in the temperate, boreal and subarctic Atlantic, south to New Jersey, and were once common from Nantucket Shoals to Labrador (Klein-MacPhee 2002d). They have been found at depths from 25-1000 m, but 700-900 m is probably the deepest they are found in any numbers. Atlantic halibut eggs are bathypelagic and are fertilized on the bottom (Cargnelli, Griesbach, and Morse 1999; Klein-MacPhee 2002d). Since eggs occur close to, but not on the bottom, scallop dredges, otter trawls, and hydraulic clam dredges are not expected to affect the functional value of the habitat for this life stage, and EFH vulnerability was rated as none. Juvenile, adult and spawning adult halibut occupy a variety of habitat types north of Nantucket Shoals. Adults are not found on soft mud or on rock bottom (Cargnelli, Griesbach, and Morse 1999). Spawning is occasionally associated with complex habitats. Juvenile halibut feed mostly on annelid worms and crustaceans, then transition to a diet of mostly fish as adults (Klein-MacPhee 2002d). EFH vulnerability to scallop dredges and otter trawls was rated as moderate for juveniles and adults. EFH vulnerability for clam dredges was rated as none since this gear type does not operate in halibut EFH (see Chapter 4 of this document).a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 134

Table 6.5. Atlantic herring EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs GOM, GB and following estuaries: Englishman/Machias Bay, Casco Bay, and Cape Cod Bay 20-80 July through November 

Bottom habitats with a substrate of gravel, sand, cobble, shell fragments, and aquatic macrophytes, tidal currents 1.5-3 knots 

L L 0 L L 

Larvae 

GOM, GB, SNE and following estuaries: Passamaquoddy Bay to Cape Cod Bay, Narragansett Bay, and Hudson R./ Raritan Bay 

50-90 

Between August and April, peaks from September to November 

Pelagic waters NA NA NA NA NA 

Juveniles 

GOM, GB, SNE and Middle Atlantic south to Cape Hatteras and following estuaries: Passamaquoddy Bay to Cape Cod Bay, Buzzards Bay to Long Island Sound, Gardiners Bay to Delaware Bay 

15-135 Pelagic waters and bottom habitats NA NA NA NA NA 

Adults 

GOM, GB, SNE and middle Atlantic south to Cape Hatteras and following estuaries: Passamaquoddy Bay to Great Bay, Massachusetts Bay to Cape Cod Bay, Buzzards Bay to Long Island Sound, Gardiners Bay to Delaware Bay, and Chesapeake Bay 

20-130 Pelagic waters and bottom habitats NA NA NA NA NA 

Spawning adults 

GOM, GB, SNE and middle Atlantic south to Delaware Bay and Englishman/Machias Bay Estuary 20-80 July through November 

Bottom habitats with a substrate of gravel, sand, cobble, and shell fragments, also on aquatic macrophytes 

L L 0 L L 

Rationale: Atlantic herring (Clupea harengus) is a coastal pelagic species ranging from Labrador to Cape Hatteras in the western Atlantic (Reid et al. 1999; Munroe 2002). For pelagic life stages (larvae, juveniles, adults) EFH vulnerability to bottom-tending fishing gears is not applicable. Atlantic herring eggs are laid in high-energy, benthic habitats on gravel, sand, or rocky substrates, and on macrophytes (Reid et al. 1999; Munroe 2002). These habitats are less susceptible to fishing gear impacts since they have evolved under a high-energy disturbance regime (strong bottom currents). Vulnerability of herring egg EFH to scallop dredges and otter trawls is considered low. Although these gears may directly affect the eggs, only the effect of the gear on the functional value of the habitat was considered for this evaluation. EFH vulnerability from clam dredges was considered to be none since this gear does not operate in areas of herring egg EFH. Spawning adults are closely associated with the bottom. Effects on the functional value of habitat from mobile gears are unknown, and were rated as low since spawning occurs on the bottom. EFH vulnerability from clam dredges was rated as none for the reasons described above. Spawning could be disrupted by noise associated with these gears, but this issue was not addressed as a habitat-related issue.a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 135

Table 6.6. Atlantic mackerel EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

Continental shelf from Maine through Cape Hatteras, also includes the following estuaries: Great Bay to Cape Cod Bay, Buzzards Bay to Long Island Sound, Gardiners Bay, and Great South Bay 

0-15 Pelagic waters NA NA NA NA NA 

Larvae 

Continental shelf from Maine through Cape Hatteras, also includes the following estuaries: Great Bay to Cape Cod Bay, Buzzards Bay to Long Island Sound, Gardiners Bay, and Great South Bay 

10-130 Pelagic waters NA NA NA NA NA 

Juveniles 

Continental shelf from GOM through Cape Hatteras, also includes the following estuaries: Passamaquoddy Bay, Penobscot Bay to Saco Bay, Great Bay, Massachusetts Bay to Cape Cod Bay, Narragansett Bay, Long Island Sound, Gardiners Bay to Hudson R./ Raritan Bay 

0-320 Pelagic waters NA NA NA NA NA 

Adults 

Continental shelf from GOM through Cape Hatteras, also includes the following estuaries: Passamaquoddy Bay to Saco Bay, Massachusetts Bay to Long Island Sound, Gardiners Bay to Hudson R./ Raritan Bay 

0-380 Pelagic waters NA NA NA NA NA 

Rationale: All life stages of Atlantic mackerel (Scomber scombrus) are pelagic, so their EFH is not vulnerable to bottom-tending fishing gear, and vulnerability was categorized as “not applicable.” a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 136

Table 6.7. Atlantic salmon EFH-vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 30-31 

Between October and April 

Bottom habitats with a gravel or cobble riffle (redd) above or below a pool in rivers 

NA NA NA NA NA 

Larvae 

Between March and June for alevins/fry 

Bottom habitats with a gravel or cobble riffle (redd) above or below a pool in rivers 

NA NA NA NA NA 

Juveniles 10-61 

Bottom habitats of shallow gravel/cobble riffles interspersed with deeper riffles and pools in rivers and estuaries, water velocities of 30-92 cm/s 

NA NA NA NA NA 

Adults 

Oceanic adult Atlantic salmon are primarily pelagic and range from waters of the continental shelf off SNE north throughout the GOM, dissolved oxygen >5 ppm for migratory pathway 

NA NA NA NA NA 

Spawning adults 

The following rivers from Connecticut to Maine: Connecticut, Pawcatuck, Merrimack, Cocheco, Saco, Androscoggin, Presumpscot, Kennebec, Sheepscot, Ducktrap, Union, Penobscot, Narraguagus, Machias, East Machias, Pleasant, St. Croix, Denny’s, Passagassawaukeag, Aroostook, Lamprey, Boyden, and Orland rivers, and Turk, Hobart and Patten Streams, and the following estuaries and embayments for juveniles and adults: Passamaquoddy Bay to Muscongus Bay, Casco Bay to Wells Harbor, Massachusetts Bay, Long Island Sound, and Gardiners Bay to Great South Bay. EFH includes all aquatic habitats in the watersheds of the above listed rivers, including all tributaries to the extent that they are currently or were historically accessible for salmon migration. 

30-61 October and November Bottom habitats with a gravel or cobble riffle (redd) above or below a pool in rivers NA NA NA NA NA 

Rationale: Atlantic salmon (Salmo salar) eggs and larvae are found in riverine areas where the fishing gears under consideration are not used, so EFH vulnerability is not applicable. It is important to note that these life stages are particularly vulnerable to non-fishing-related impacts such as point-source discharges and polluted runoff. Juveniles and adults are pelagic in nature, and vulnerability of EFH to bottom-tending fishing gear is not applicable for these life stages. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 137

Table 6.8. Atlantic surfclam EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage

Geographic Area of

EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Juveniles 

Eastern edge of GB and the GOM throughout Atlantic EEZ 

0-60, low 

density 

beyond 38 

Throughout substrate to a depth of 3 ft within federal waters, burrow in medium to coarse sand and gravel substrates, also found in silty to fine sand, but not in mud 

L L L L L 

Adults 

Eastern edge of GB and the GOM throughout Atlantic EEZ 

0-60, low 

density 

beyond 38 

Spawn summer to fall 

Throughout substrate to a depth of 3 ft within federal waters L L L L L 

Rationale: Atlantic surfclams (Spisula solidissima) are found in sandy continental shelf habitats from the southern Gulf of St. Lawrence to Cape Hatteras, North Carolina (Cargnelli et al. 1999a). They burrow into substrates from fine to coarse sandy gravel, and are not found in mud. Although clam dredges remove clams from the sediment, the habitat’s functional value is probably not affected. Juvenile and adult EFH vulnerability was therefore rated as low for all mobile gears. Surfclam eggs and larvae are pelagic, therefore EFH vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 

Table 6.9. Barndoor skate EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic Clam

Dredge

Pots and 

Traps

Sink Gill 

Nets and Bottom

Longlines

Juveniles 

Eastern GOM, GB, SNE, MidAtlantic Bight to Hudson Canyon 

0-750, 

mostly <150 

Bottom habitats with mud, gravel, and sand substrates M M L L L 

Adults 

Eastern GOM, GB, SNE, MidAtlantic Bight to Hudson Canyon 

0-750, 

mostly <150 

Bottom habitats with mud, gravel, and sand substrates M M L L L 

Rationale: Barndoor skate (Dipturus laevis) occur from Newfoundland south to Cape Hatteras, but are most abundant on GB and in the GOM. They are found on soft mud, sand, and gravel (Packer etal. 2003a). Barndoor skate feed on invertebrates usually associated with the bottom, including polychaetes, gastropods, and bivalves, as well as squid and fish. Smaller individuals feed primarily on polychaetes, copepods, and amphipods, while larger individuals capture larger and more active prey (McEachran 2002, Packer et al. 2003a). A single fertilized egg is encapsulated in a leathery capsule known as a “mermaids purse.” The young hatch in late spring or early summer, and are thought to be about 18-19 cm in length, although very little information is available on this life stage (Packer etal. 2003a). Juvenile EFH was considered to be moderately vulnerable to otter trawls and scallop dredges because of the closer association of juveniles to a benthic invertebrate diet. Adult EFH vulnerability to otter trawls and scallop dredges was rated as moderate due primarily to their reproductive habits. EFH vulnerability to clam dredges was rated as low for juveniles and adults because this gear is not extensively used in EFH. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 138

Table 6.10. Black sea bass EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs Continental shelf and estuaries from SNE to North Carolina; also includes Buzzards Bay 0-200 May to October Water column of coastal Mid- Atlantic Bight and Buzzards Bay NA NA NA NA NA Larvae 

Pelagic waters over continental shelf from GOM to Cape Hatteras; also includes Buzzards Bay 

<100 May to November, peak June to July 

Habitats for transforming (to juveniles) larvae are near coastal areas and into marine parts of estuaries between Virginia and NY; when larvae become demersal, found on structured inshore habitat such as sponge beds 

H H H L L 

Juveniles 

Demersal waters over continental shelf from GOM to Cape Hatteras, also includes the following estuaries: Buzzards Bay to Long Island Sound, Gardiners Bay, Barnegat Bay to Chesapeake Bay, Tangier/Pocomoke Sound, and James R 

1-38 

Found in coastal areas (April to December, peak June to November) between Virginia and Massachusetts, but winter offshore from New Jersey south; in estuaries in summer and spring 

Rough bottom, shellfish and eelgrass beds, man-made structures in sandy-shelly areas, offshore clam beds, and shell patches may be used during wintering 

H H H L L 

Adults 

Demersal waters over continental shelf from GOM to Cape Hatteras, also includes the following estuaries: Buzzards Bay, Narragansett Bay, Gardiners Bay, Great South Bay, Barnegat Bay to Chesapeake Bay, Tangier/Pocomoke Sound, and James R 

20-50 

Wintering adults (November to April) offshore, south of New York to North Carolina; inshore, in estuaries from May to October 

Structured habitats (natural and man-made), sand and shell substrates preferred 

H H H L L 

Rationale: Black sea bass (Centropristis striata) are found in coastal waters of the northwest Atlantic, from Cape Cod south to Cape Canaveral (Klein-MacPhee 2002e). Occasionally they stray as far north as the Bay of Fundy (GOM). Juveniles are common in high-salinity estuaries. Adults and juveniles are found in estuaries from Massachusetts south to the James River, Virginia (Stone et al. 1994). Black sea bass larvae are pelagic, but then become demersal and occupy structured inshore habitat such as sponge beds, eelgrass beds, shellfish beds, shell patches, and other rough bottoms (Steimle, Zetlin, Berrien, and Chang 1999) and offshore shell patches including clam beds (Able and Fahay 1998). The availability of structure limits successful post-larval and/or juvenile recruitment (Steimle, Zetlin, Berrien, and Chang 1999). Juveniles are diurnal visual predators that feed on benthic invertebrates and small fish. Adults are also structure oriented, and are thought to use structure as shelter during the day, but may stray off it to hunt at night. Each of these life stages is associated with structure that may be vulnerable to fishing gear impacts, so vulnerability was rated as high for all mobile gears. It is important to note that structured habitats comprised of wrecks or other artificial reefs prone to damage by mobile gear may be avoided by fishermen. This is true of high-relief natural areas as well. Black sea bass eggs are pelagic, so vulnerability to EFH is not applicable. Although larvae are pelagic, they do become demersal as they transition into juveniles. Therefore, larvae were rated the same as juveniles. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 139

Table 6.11. Bluefish EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

North of Cape Hatteras--over continental shelf from Montauk Point south to Cape Hatteras; south of Cape Hatteras--over continental shelf through Key West, Florida 

Midshelf 

depths 

April to August Pelagic waters NA NA NA NA NA 

Larvae 

North of Cape Hatteras--over continental shelf from Montauk Point south to Cape Hatteras; south of Cape Hatteras--over continental shelf through Key West, the slope sea, and Gulf Stream between latitudes 29°N and 40°N; includes Narragansett Bay 

> 15 April to September Pelagic waters NA NA NA NA NA 

Juveniles 

North of Cape Hatteras--over continental shelf from Nantucket Island south to Cape Hatteras; south of Cape Hatteras--over continental shelf through Key West, the slope sea, and Gulf Stream between latitudes 29°N and 40°N; also includes the following estuaries: Penobscot Bay to Great Bay, Massachusetts Bay to James R., Albemarle Sound to St. Johns R. 

North Atlantic estuaries from June to October; mid-Atlantic estuaries from May to October; South Atlantic estuaries from March to December 

Pelagic waters NA NA NA NA NA 

Adults 

North of Cape Hatteras--over continental shelf from Cape Cod Bay south to Cape Hatteras; south of Cape Hatteras--found over continental shelf through Key West: also includes the following estuaries: Penobscot Bay to Great Bay, Massachusetts Bay to James R., Albemarle Sound to Pamilco/Pungo R., Bougue Sound, Cape Fear R., St. Helena Sound, Broad R., St. Johns R., and Indian R. 

North Atlantic estuaries from June to October; mid-Atlantic estuaries from April to October; South Atlantic estuaries from May to January 

Pelagic waters NA NA NA NA NA 

Rationale: All life stages of bluefish (Pomatomus saltatrix) are pelagic, so their EFH is not vulnerable to bottom-tending fishing gears, and vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 140

Table 6.12. Butterfish EFH-vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

Over continental shelf from GOM through Cape Hatteras; also estuaries, including Massachusetts Bay to Long Island Sound, Gardiners Bay, Great South Bay, and Chesapeake Bay 

0-1829 Spring and 

summer Pelagic waters NA NA NA NA NA 

Larvae 

Over continental shelf from GOM through Cape Hatteras; also estuaries, including Boston Harbor, Waquoit Bay to Long Island Sound, Gardiners Bay to Hudson R./Raritan Bay, Delaware Bay, and Chesapeake Bay 

10-1829 Summer and fall Pelagic waters NA NA NA NA NA 

Juveniles 

Over continental shelf from GOM through Cape Hatteras; also estuaries, including Massachusetts Bay, Cape Cod Bay to Delaware inland bays, Chesapeake Bay, York R., and James R. 

10-365 

(most 

<120) 

Winter--shelf; spring to fall--estuaries 

Pelagic waters (larger individuals found over sandy and muddy substrates) 

NA NA NA NA NA 

Adults 

Over continental shelf from GOM through Cape Hatteras; also estuaries, including Massachusetts Bay, Cape Cod Bay to Hudson R./Raritan Bay, Delaware Bay and inland bays, York R., and James R. 

10-365 

(most 

<120) 

Winter--shelf; summer to fall--estuaries 

Pelagic waters (schools form over sandy, sandy silt, and muddy substrates)

NA NA NA NA NA 

Rationale: All life stages of butterfish (Peprilus triacanthus) are pelagic, so their EFH is not vulnerable to bottom-tending fishing gear, and vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 141

Table 6.13. Clearnose skate EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam Dredge 

Pots and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Juveniles 

GOM, along shelf to Cape Hatteras ; includes the estuaries from Hudson River/Raritan Bay south to the Chesapeake Bay mainstem 

0 – 500, mostly < 111 

Bottom habitats with substrate of soft bottom along continental shelf, and rocky or gravelly bottom 

M M M L L 

Adults 

GOM, along shelf to Cape Hatteras ; includes the estuaries from Hudson River/Raritan Bay south to the Chesapeake Bay mainstem 

0 – 500, mostly < 111 

Bottom habitats with substrate of soft bottom along continental shelf, and rocky or gravelly bottom 

M M M L L 

Rationale: Clearnose skate (Raja eglanteria) occur in the GOM, but are most abundant from Cape Hatteras north to Delaware Bay. They are found over soft bottoms of mud and sand, as well as on rocky or gravelly bottoms. They have been captured from shore out to depths of 330 m, but are most abundant at depths less than 111 m (Packer et al. 2003b). Adults and juveniles feed on polychaetes, amphipods, decapod crustaceans, mollusks, and fish. Like barndoor skates, crabs and benthic invertebrates are more important for smaller, younger individuals, and the importance of fish in the diet increases with age (McEachran 2002; Packer et al. 2003b). A single fertilized egg is encapsulated in a leathery case. Eggs are deposited in the spring or summer, and hatch 3 mo later. Juvenile EFH was considered moderately vulnerable to otter trawls, scallop dredges, and clam dredges because of the close association of juveniles to a benthic invertebrate diet. Adult EFH vulnerability to otter trawls, scallop dredges, and clam dredges was rated as moderate due primarily to the species’ reproductive habits. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 

Table 6.14. Cobia EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage

Geographic Area 

of EFHa

Depth

(m)

Seasonal

Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam Dredge 

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

All life stages 

South Atlantic and Mid-Atlantic Bights 

Sandy shoals of capes and offshore bars; high-profile rock bottoms and barrier island oceanside waters from surf zone to shelf break, but from the Gulf Stream shoreward; also high salinity bays, estuaries, seagrass habitat 

NA NA NA NA NA 

Rationale: All life stages of cobia (Rachycentron canadum) are pelagic, so their EFH is not vulnerable to bottom tending fishing gear, and vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 142

Table 6.15. Golden deepsea crab EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

All life stages 

Chesapeake Bay to the south through the Florida Straight (and into the Gulf of Mexico) 

290-

570 

Continental slope in flat areas of foraminifera ooze, on distinct mounds of dead coral, ripple habitat, dunes, black pebble habitat, low outcrop, and soft bioturbated habitat 

L 0 0 L L 

Rationale: The golden deepsea crab (Chaceon fenneri) inhabits the continental slope of Bermuda and the southeastern United States from Chesapeake Bay south through the Florida Straight and into the Gulf of Mexico (SAFMC 1998). Although similar to the red deepsea crab, less is known about this species. They are categorized as opportunistic scavengers, and are found in depths from 290-570 m on substrates of foraminiferon ooze, dead coral mounds, deep ripple habitat, dunes, and black pebble habitat. Scallop dredges and clam dredges do not operate in golden crab EFH due to depth, so EFH vulnerability was rated as none. Most otter trawling operates in depths less than 200 m so EFH vulnerability was rated as low for this gear type. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 143

Table 6.16. Goosefish EFH-vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs GOM, GB, SNE, middle Atlantic south to Cape Hatteras 15-1000 March to September Surface waters NA NA NA NA NA Larvae 

GOM, GB, SNE, middle Atlantic south to Cape Hatteras 25-1000 March to September Pelagic waters NA NA NA NA NA 

Juveniles 

Outer continental shelf in the middle Atlantic, mid-shelf off SNE, all areas of GOM 

25-200 

Bottom habitats with substrates of a sand-shell mix, algae-covered rocks, hard sand, pebbly gravel, or mud 

L L L L L 

Adults 

Outer continental shelf in the middle Atlantic, mid-shelf off SNE, outer perimeter of GB, all areas of GOM 

25-200 

Bottom habitats with substrates of a sand-shell mix, algae-covered rocks, hard sand, pebbly gravel, or mud 

L L L L L 

Spawning adults 

Outer continental shelf in the middle Atlantic, mid-shelf off SNE, outer perimeter of GB, all areas of GOM 

25-200 February to August Bottom habitats with substrates of a sand-shell mix, algae-covered rocks, hard sand, pebbly gravel, or mud L L L L L 

Rationale: Goosefish (Lophius americanus), are demersal anglerfish found from Newfoundland south to Florida, but are common only north of Cape Hatteras (Steimle, Morse, and Johnson 1999). Juveniles are primarily found at depths between 40 and 75 m, while adults are concentrated between 50-100 m. In the GOM, adults occur primarily between the depths of 130-260 m. Occasionally, adults are seen at the surface. Both juveniles and adults (including spawning adults) occur on substrates ranging from mud to gravelly sand, algae, and rocks. A goosefish has been observed digging depressions in the bottom substrate with its pectoral fins until its back was almost flush with the surrounding bottom (Caruso 2002). The goosefish is a sight predator that uses its highly modified first dorsal fin as an angling apparatus to lure small fishes towards its mouth (Caruso 2002). Goosefish eat a wide array of prey items, but mainly fish and cephalopods. Goosefish have been reported to ingest a variety of seabirds. There are no indications in the literature that any goosefish life stage is habitat limited or that the functional value of its habitat could be adversely affected by fishing. Vulnerability of adult and juvenile EFH to mobile fishing gear was rated as low. Goosefish eggs and larvae are pelagic, and vulnerability to bottom-tending fishing gear is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 144

Table 6.17. Haddock EFH-vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GB southwest to Nantucket Shoals, coastal areas of GOM, and the following estuaries: Great Bay, Massachusetts Bay, Boston Harbor, Cape Cod Bay, Buzzards Bay 

50-90 March to May, peaks in April Surface waters NA NA NA NA NA 

Larvae 

GB southwest to Delaware Bay, and the following estuaries: Great Bay, Massachusetts Bay, Boston Harbor, Cape Cod Bay, Buzzards Bay, and Narragansett Bay 

30-90 

January to July, peaks in April and May 

Surface waters NA NA NA NA NA 

Juveniles GB, GOM, and middle Atlantic south to Delaware Bay 35-100 Bottom habitats with a substrate of pebble and gravel H H L L L Adults GOM, GB, Nantucket Shoals, and the Great South Channel 40-150 

Bottom habitats with a substrate of broken ground, pebbles, smooth hard sand, and smooth areas between rocky patches 

H H L L L 

Spawning adults 

GOM, GB, Nantucket Shoals, and the Great South Channel 40-150 January to June Bottom habitats with a substrate of pebble, gravel, or gravelly sand H H L L L 

Rationale: Haddock (Melanogrammus aeglefinus) are found from Greenland to Cape Hatteras and are common throughout the GOM, Georges Bank, and SNE (Cargnelli, Griesbach, Berrien, et al.1999; Klein-MacPhee 2002a). Juveniles older than 3 mo and adults are demersal and generally found in waters from 10-150 m in depth. Juveniles are usually found in waters shallower than 100 m. Haddock spawn over pebble and gravel substrate, and avoid ledges, rocks, kelp, and soft mud (Cargnelli, Griesbach, Berrien, et al. 1999). Haddock eggs and larvae are pelagic, and EFH vulnerability to fishing gear is not applicable. Juvenile haddock, like juvenile cod, may benefit, perhaps strongly, from physical and biological complexity (see discussion in Chapter 2). In general, haddock have a stronger benthic affinity than cod (Klein-MacPhee 2002a). Juvenile haddock are chiefly found over pebble and gravel substrates (Cargnelli, Griesbach, Berrien, et al. 1999). Once demersal, they feed on benthic fauna, and their primary prey items are crustaceans and polychaetes. The habitat complexity that appears to be important to juvenile haddock can be reduced by otter trawls and scallop dredges, and benthic prey may be affected (see Chapter 5). Juvenile haddock EFH are considered highly vulnerable to these two gear types. Vulnerability to clam dredges was rated as low since there is some use of this gear in juvenile EFH. Adult haddock are found on broken ground, gravel, pebbles, clay, smooth sand, and sticky sand of gritty consistency, with a preference for smooth areas around rock patches (Klein-MacPhee 2002a). They feed indiscriminately on benthic invertebrates, and occasionally on fish. Adults (including spawning adults) occupy a variety of habitat types that might be affected by otter trawls and scallop dredges. Adults may be less closely linked to complex habitats then juveniles, but there is still some association. Haddock are expected to be more strongly linked to benthic habitats than cod, since haddock primarily feed on benthic invertebrates, while cod are primarily piscivorous. Benthic prey resources for haddock may be adversely affected by scallop dredges or otter trawls in areas of lower energy and expected slower habitat recovery. Overall, adult EFH vulnerability to these gear types was rated as high. Clam dredges operate only in sand, and the associated recovery period is short (Table 5.15). Moreover, clam dredging is not expected to create a chronic disturbance in these areas since the population of clams, which are benthic infauna, must recover before fishing is again profitable; therefore, habitat vulnerability for clam dredges was rated as low. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 145

Table 6.18. King mackerel EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage 

Geographic Area 

of EFHa

Depth

(m) 

Seasonal

Occurrence EFH Description Otter 

Trawl 

New 

BedfordStyle

ScallopDredge

Hydraulic

Clam Dredge 

Pots 

and

Traps

Sink Gill 

Nets and 

Bottom 

Longlines

All life stages 

South Atlantic and Mid-Atlantic Bights 

Sandy shoals of capes and offshore bars; high-profile rock bottoms and barrier island oceanside waters from surf zone to shelf break, but from the Gulf Stream shoreward, also high salinity bays, estuaries, seagrass habitat 

NA NA NA NA NA 

Rationale: All life stages of king mackerel (Scomberomorus cavalla) are pelagic, so their EFH is not vulnerable to bottom-tending fishing gear, and vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 

Table 6.19. Little skate EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and Bottom

Longlines

Eggs 

GB to Cape Hatteras; includes the estuaries from Buzzards Bay south to the Chesapeake Bay mainstem 

<27 Bottom habitats with sandy substrate L L L L L 

Juveniles 

GB to Cape Hatteras; includes the estuaries from Buzzards Bay south to the Chesapeake Bay mainstem 

0-137, 

mostly 73-

91 

Bottom habitats with sandy or gravelly substrate or mud M M M L L 

Adults 

GB to Cape Hatteras; includes the estuaries from Buzzards Bay south to the Chesapeake Bay mainstem 

0-137, 

mostly 73-

91 

Bottom habitats with sandy or gravelly substrate or mud M M M L L 

Rationale: Little skate (Leucoraja erinacea) range from Nova Scotia to Cape Hatteras, and are most abundant on GB and in coastal waters south to the mouth of Chesapeake Bay. They have been found at depths up to 500 m, but are most common at depths less than 111 m (Packer et al. 2003c). In SNE, juveniles and adults have been associated with microhabitat features including biogenic depressions and flat sand during the day (Auster et al. 1991, 1995). They are generally found on sandy or gravelly bottoms, but also occur on mud. They co-occur with winter skate, and are more active at night, although they appear to feed throughout the day and night. The most important prey are amphipods and decapod crustaceans, followed by polychaetes (Packer et al. 2003c). Prey items of minor importance include bivalves, isopods, and fish. Similar to barndoor and clearnose skates, the use of fish as a food source increases with increasing size. Smaller skates eat more amphipods, and larger skate consume more decapod crustaceans (Packer et al. 2003c). A single fertilized egg is encapsulated in a leathery case that is deposited on sandy substrate. The cases have sticky filaments that adhere to bottom substrates. In one study, eggs deposited in the late spring and early summer required 5 to 6 mo to hatch. Other studies have shown incubation to exceed 1 yr. When the young hatch, they are considered juveniles and are fully developed asuring from 93-102 mm in total length (Packer et al. 2003c). Vulnerability of juvenile EFH to mobile bottom gear was characterized as moderate because of the species dependence on benthic organisms in its diet. Vulnerability of adult EFH to mobile bottom geargears was characterized as moderate due to its reproductive habits. Little skate is the only skate species in which EFH has been designated for eggs. Although bottom-tending mobile gears may have adverse effects upon the eggs themselves, this was not considered to be a habitat impact. Since the bottom substrate appears to provide an attachment point for the eggs, the EFH vulnerability to mobile gear was rated as low instead of none. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 146

Table 6.20. Longfin inshore squid EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic Clam

Dredge

Pots and 

Traps

Sink Gill 

Nets and Bottom

Longlines

 Juveniles Over continental shelf from GOM through Cape Hatteras 0-213 Inshore spring to fall; offshore in winter Pelagic waters NA NA NA NA NA Adults Over continental shelf from GOM through Cape Hatteras 0-305 Inshore March to October; offshore in winter Pelagic waters NA NA NA NA NA Rationale: Longfin inshore squid (Loligo pealeii) is a pelagic schooling species. It is distributed in continental shelf and slope waters from Newfoundland to the Gulf of Venezuela (Cargnelli, Griesbach, McBride, et al. 1999). Most life stages of longfin inshore squid are pelagic; however, encapsulated eggs are laid in masses, called “mops,” that are attached to structures such as rocks and algae on substrates of sand, mud, or on hard-bottom in depths <50m (Cargnelli, Griesbach, McBride, 1999). As of this writing, EFH has not been designated for longfin inshore squid eggs. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. Table 6.21. Northern shortfin squid EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Juveniles Over continental shelf from GOM through Cape Hatteras 0-182 Carried northward by Gulf Stream Pelagic waters NA NA NA NA NA  Adults Over continental shelf from GOM through Cape Hatteras 0-182 Offshore late fall; spawn December to March Pelagic waters NA NA NA NA NA Rationale: All stages of northern shortfin squid (Illex illecebrosus) are pelagic, so their EFH is not vulnerable to bottom tending fishing gear, and vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 147

Table 6.22. Ocean pout EFH-vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GOM, GB, SNE, middle Atlantic south to Delaware Bay, and the following estuaries: Passamaquoddy Bay to Saco Bay, Massachusetts Bay, and Cape Cod Bay 

<50 Late fall and winter 

Bottom habitats, generally hardbottom sheltered nests, holes, or crevices where they are guarded by parents 

H H H L L 

Larvae 

GOM, GB, SNE, middle Atlantic south to Delaware Bay, and the following estuaries: Passamaquoddy Bay to Saco Bay, Massachusetts Bay, and Cape Cod Bay 

<50 Late fall to spring 

Bottom habitats in close proximity to hard-bottom nesting areas 

H H H L L 

Juveniles 

GOM, GB, SNE, middle Atlantic south to Delaware Bay, and the following estuaries: Passamaquoddy Bay to Saco Bay, Massachusetts Bay, Boston Harbor, and Cape Cod Bay 

<80 Bottom habitats, often smooth bottom near rocks or algae H H H L L 

Adults 

GOM, GB, SNE, middle Atlantic south to Delaware Bay, and the following estuaries: Passamaquoddy Bay to Saco Bay, Massachusetts Bay, Boston Harbor, and Cape Cod Bay 

<110 

Bottom habitats; dig depressions in soft sediments which are then used by other species 

H H H L L 

Spawning adults 

GOM, GB, SNE, middle Atlantic south to Delaware Bay, and the following estuaries: Passamaquoddy Bay to Saco Bay, Massachusetts Bay, and Cape Cod Bay 

<50 

Late summer to early winter, peaks in September and October 

Bottom habitats with a hardbottom substrate, including artificial reefs and shipwrecks 

H H H L L 

Rationale: Ocean pout (Zoarces americanus) is a demersal species found in the western Atlantic from Labrador south to Cape Hatteras (Steimle, Morse, Berrien, Johnson, and Zetlin 1999). It can occur in deeper waters south of Cape Hatteras, and has been found as deep as 363 m (Klein-MacPhee and Collette 2002a). It is found in most estuaries and embayments in the GOM, and is caught by the NEFSC trawl surveys in greatest abundance off SNE (Steimle, Morse, Berrien, Johnson, and Zetlin 1999). Ocean pout eggs are laid in nests in crevices, on hard-bottom, or in holes and protected by the female parent for 2.5-3 mo until they hatch (Klein-MacPhee and Collette 2002a). Potential impacts to habitat from otter trawls, scallop dredges, and clam dredges include knocking down boulder piles, removing biogenic structure, and filling in bottom depressions, which may disturb nests and/or leave these areas less suitable for nests. In addition, fishing may frighten parents from nests leaving eggs susceptible to predation. Egg EFH is therefore considered to have a high vulnerability to all bottom-tending mobile gears. Ocean pout have a relatively short larval stage, and some authors (KleinMacPhee and Collette 2002a) suggest that there is no larval stage (Steimle, Morse, Berrien, Johnson, and Zetlin 1999). Since the NEFMC designated EFH for this life stage, it is considered here. Larvae (hatchlings) remain near the nest site; however, there is little information on their use of habitats. Larvae do not appear to be as closely associated with the bottom as eggs or juveniles; however, it is anticipated that loss of structure may impact larvae to some degree. Larval EFH was determined to have high vulnerability to mobile bottom-tending gears. Juvenile pout are found under rocks, shells and algae, in coastal waters and are closely associated with the bottom (Steimle, Morse, Berrien, Johnson, and Zetlin 1999). They feed on benthic invertebrates such as gammarid amphipods and polychaetes. It is expected that loss of structure may significantly impact juvenile EFH. Vulnerability of juvenile EFH to all mobile gears was considered high. Adult pout are found in sand and gravel in winter and spring, and in rocky/hard substrate areas for spawning and nesting (Klein-MacPhee and Collette 2002a). They create burrows in soft sediments, and their diet consists mainly of benthic invertebrates including mollusks, crustaceans, and echinoderms. Because of the strong benthic affinity of ocean pout, it is anticipated that vulnerability of adult EFH to all mobile gears is high. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 148

Table 6.23. Ocean quahog EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage

Geographic Area of

EFHa

Depth

(m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Juveniles 

Eastern edge of GB and GOM throughout the EEZ 

8-245 

Throughout substrate to a depth of 3 ft within federal waters; occurs progressively farther offshore between Cape Cod and Cape Hatteras 

L L L L L 

Adults 

Eastern edge of GB and GOM throughout the EEZ 

8-245 

Spawn May to December with several peaks 

Throughout substrate to a depth of 3 ft within federal waters; occurs progressively farther offshore between Cape Cod and Cape Hatteras 

L L L L L 

Rationale: Ocean quahog (Arctica islandica) juveniles are found in offshore sandy substrate, and may survive in muddy intertidal areas (Cargnelli et al. 1999b). Adults are found in similar offshore habitats, just below the surface of the sediment, usually in medium- to fine-grained sand. Although clam dredges remove clams from the sediment, the habitat’s functional value is probably not affected. Juvenile and adult EFH vulnerability was therefore rated as low for all mobile gears. Ocean quahog eggs and larvae are pelagic, therefore EFH vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 149

Table 6.24. Offshore hake EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic Clam

Dredge

Pots and 

Traps

Sink Gill 

Nets and Bottom

Longlines

Eggs Outer continental shelf of GB and SNE south to Cape Hatteras <1250 Observed all year and primarily collected at depths from 110-270 m Pelagic waters NA NA NA NA NA Larvae Outer continental shelf of GB and SNE south to Chesapeake Bay <1250 Observed all year and primarily collected at depths from 70-130m Pelagic waters NA NA NA NA NA Juveniles Outer continental shelf of GB and SNE south to Cape Hatteras 170-350 Bottom habitats L L 0 L L Adults Outer continental shelf of GB and SNE south to Cape Hatteras 150-380 Bottom habitats L L 0 L L Spawning adults 

Outer continental shelf of GB and SNE south to the Middle Atlantic Bight 

330-550 Spawn throughout the year Bottom habitats L L 0 L L 

Rationale: Offshore hake (Merluccius albidus) are distributed over the continental shelf and slope of the Northwest Atlantic, ranging from the Grand Banks south to the Caribbean and Gulf of Mexico (Chang, Berrien, Johnson, and Zetlin 1999; Klein-MacPhee 2002f). Juveniles and adults are found in deeper waters, and are most abundant at depths between 150-380 m. They are an important component in the slope community off Florida, and are reportedly caught near the outer edge of the Scotian Shelf, and on the slopes of deep basins in the GOM and the continental slope from the southeastern edge of GB south. Because of their depth preference, very little is known about the offshore component of the stock. Moreover, offshore hake are similar in appearance to silver hake, and may have been misidentified in earlier studies. They are taken commercially as bycatch in the silver hake fishery. No information is available on substrate preferences for juveniles and adults. Eggs and larvae are pelagic, and EFH vulnerability to fishing gears is not applicable. Juvenile and adult offshore hake appear to feed at or near the bottom, and are primarily piscivorous (feeding particularly on clupeids, anchovies, and lanternfishes), but they also eat crustaceans and squid (Klein-MacPhee 2002f). There is evidence of adult diel vertical migration. Only limited information exists about this species, and none of it indicates that offshore hake have a very strong bottom affinity, or that impacts from fishing gear would affect the functional value of their habitat. Although spawning occurs near the bottom, the actual use of benthic habitat during spawning is unknown. The vulnerability of adult and juvenile EFH to otter trawls and scallop dredges is expected to be low. Vulnerability to clam dredges was rated as none since the gear does not operate in the EFH of this species. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 150

Table 6.25. Pollock EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs GOM, GB, and the following estuaries: Great Bay to Boston Harbor 30–270 October to June, peaks November to February Pelagic waters NA NA NA NA NA Larvae 

GOM, GB, and the following estuaries: Passamaquoddy Bay, Sheepscot R., and Great Bay to Cape Cod Bay 

10–250

September to July, peaks December to February 

Pelagic waters NA NA NA NA NA 

Juveniles 

GOM, GB, and the following estuaries: Passamaquoddy Bay to Saco Bay, Great Bay to Waquoit Bay, Long Island Sound, and Great South Bay 

0–250 

Bottom habitats with aquatic vegetation or a substrate of sand, mud, or rocks 

L L L L L 

Adults 

GOM, GB, SNE, and middle Atlantic south to New Jersey, and the following estuaries: Passamaquoddy Bay, Damariscotta R., Massachusetts Bay, Cape Cod Bay, and Long Island Sound 

15–365 Hard-bottom habitats, including artificial reefs M M L L L 

Spawning adults 

GOM, SNE, and middle Atlantic south to New Jersey, including Massachusetts Bay 15–365

September to April, peaks December to February 

Bottom habitats with a substrate of hard, stony, or rocky bottom; includes artificial reefs 

M M L L L 

Rationale: Pollock (Pollachius virens) range from the Hudson straits to North Carolina (Klein-MacPhee 2002a), and are most common on the Scotian Shelf, Georges Bank, the Great South Channel, and GOM (Cargnelli, Griesbach, Packer, Berrien, Johnson, et al. 1999). They segregate into schools by size, and avoid water warmer than about 15oC (Klein-MacPhee 2002a). They are active fish that live at any depth between the bottom and the surface, depending upon food supply. They are associated with coastal areas and offshore shoals, and are found from shore out to depths of about 325 m, but are most common from 75-175 m (Cargnelli, Griesbach, Packer, Berrien, Johnson, et al. 1999). Juveniles frequently occupy the rocky intertidal zone, which may serve as a nursery area (KleinMacPhee 2002a). Neither adults nor juveniles are selective in substrate type. Pollock are opportunistic, and the diet of both juveniles and adults consists mainly of euphausiid crustaceans, but fish, other crustaceans and squid, are also eaten (Cargnelli, Griesbach, Packer, Berrien, Johnson, et al. 1999; Klein-MacPhee 2002a). Adults spawn over broken bottom and the slopes of offshore banks, and eggs are pelagic. Based on food habits, and the distribution and behavior of pollock, vulnerability of juvenile EFH to benthic mobile gear was characterized as low. Since pollock spawn on the bottom, the vulnerability of adult EFH to otter trawls and scallop dredges was rated as moderate. EFH vulnerability from clam dredges was rated as low for juveniles and adults since there is limited use of this gear in pollock EFH. Pollock eggs and larvae are pelagic, so EFH vulnerability to fishing gear is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 151

Table 6.26. Red deepsea crab EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic Clam

Dredge

Pots and 

Traps

Sink Gill 

Nets and Bottom

Longlines

Eggs Southern flank of GB and south to Cape Hatteras 200-400 Attached to the underside of the female crab until hatched--see spawning adults NA NA NA NA NALarvae Southern flank of GB and south to Cape Hatteras 200- 1800 January to June Water column from surface to seafloor NA NA NA NA NAJuveniles Southern flank of GB and south to Cape Hatteras 700- 1800 Bottom habitats of continental slope with a substrate of silts, clays, and all silt-clay- sand composites L 0 0 L LAdults Southern flank of GB and south to Cape Hatteras 200- 1300 Bottom habitats of continental slope with a substrate of silts, clays, and all silt-clay- sand composites L 0 0 L LSpawning adults

Southern flank of GB and south to Cape Hatteras

200-

1300 

Bottom habitats of continental slope with a substrate of silts, clays, and all silt-claysand composites L 0 0 L L

Rationale: Red deepsea crab (Chaeceon (Geryon) quinquedens) are found on the outer continental shelf and slope of the western Atlantic from Nova Scotia into the Gulf of Mexico (Steimle et al. 2001). They are found on the bottom, chiefly in water depths of 200-1800. EFH depth range for juveniles is from 700-1800 m, and for adults is from 200-1300 m. They are found on substrates ranging from silt and clay to hard substrates. Red crab are opportunistic benthic feeders/scavengers, with a diet of epifauna and other opportunistically available items (Steimle et al. 2001). Post-larval juveniles feed on a wide variety of infaunal and epifaunal benthic invertebrates. Small crabs eat sponges, hydroids, gastropods, and other organisms. Larger crabs eat similar small benthic fauna and larger prey including demersal and midwater fishes. The only fishery using mobile bottom gear that operates in red crab EFH is the goosefish trawl fishery (NEFMC 2002). The vulnerability of adult and juvenile red crab EFH to otter trawls was characterized as low because of their opportunistic feeding habits. Vulnerability to scallop dredges and clam dredges was rated as none since those gears do not operate in red crab EFH. Larval red crabs are pelagic and EFH vulnerability is not applicable. The “habitat” for eggs is the female carapace, therefore EFH vulnerability for this life stage is also not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 152

Table 6.27. Red drum EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage

Geographic Area of

EFHa

Depth

(m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Larvae 

Along the Atlantic coast from Virginia through the Florida Keys 

<50 

Estuarine wetlands are especially important (flooded saltmarshes, brackish marsh, tidal creeks, mangrove fringe, seagrasses) 

NA NA NA NA NA 

Juveniles 

Along the Atlantic coast from Virginia through the Florida Keys 

<50 

Found throughout Chesapeake Bay from September to November 

Utilize shallow backwaters of estuaries as nursery areas and remain until they move to deeper water portions of the estuary associated with river mouths, oyster bars, and front beaches 

L 0 0 L L 

Adults 

Along the Atlantic coast from Virginia through the Florida Keys 

<50 

Found in Chesapeake in spring and fall, and also along eastern shore of VA 

Concentrate around inlets, shoals, and capes along the Atlantic coast; shallow bay bottoms or oyster reef substrate preferred, also nearshore artificial reefs 

L L L L L 

Rationale: Red drum (Sciaenops ocellatus) are distributed in estuarine and coastal waters depending upon their stage of maturity (McGurrin 1994). Juvenile red drum are found in shallow estuarine backwaters, and as they grow, they move to deeper areas. Submerged aquatic vegetation (SAV) is particularly important habitat for juvenile drum. Subadult and adult red drum are found on estuarine bay bottoms or oyster reefs, and in nearshore coastal waters including the beach zone out to several miles from shore. Juvenile and adult red drum have a varied diet. Smaller juveniles eat copepods and mysids, while larger individuals eat decapod crustaceans (crabs and shrimp), fish, and plant material (McGurrin 1994). Although SAV is an important habitat for juvenile red drum, EFH vulnerability to otter trawls was rated as low since its use in SAV is limited. Scallop dredges and hydraulic clam dredges usually are not used in juvenile red drum EFH; therefore, EFH vulnerability for these gears was rated as none. Since red drum feed on a variety of organisms, and adults are found in many habitat types, vulnerability of adult EFH to mobile bottom gear was rated as low. Red drum eggs and larvae are pelagic; therefore, EFH vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 153

Table 6.28. Red hake EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GOM, GB, continental shelf off SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Sheepscot R., Great Bay to Cape Cod Bay, Buzzards Bay, and Narragansett Bay 

May to November, peaks in June and July 

Surface waters of inner continental shelf NA NA NA NA NA 

Larvae 

GOM, GB, continental shelf off SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Sheepscot R., Massachusetts Bay to Cape Cod Bay; Buzzards Bay, Narragansett Bay and Hudson R./ Raritan Bay 

<200 

May to December, peaks in September and October 

Surface waters NA NA NA NA NA 

Juveniles 

GOM, GB, continental shelf off SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Passamaquoddy Bay to Saco Bay; Great Bay, Massachusetts Bay to Cape Cod Bay, Buzzards Bay to Connecticut. R., Hudson R./ Raritan Bay, and Chesapeake Bay 

<100 

Bottom habitats with substrate of shell fragments, including areas with an abundance of live sea scallops 

H H H L L 

Adults 

GOM, GB, continental shelf off SNE, and middle Atlantic south to Cape Hatteras and the following estuaries: Passamaquoddy Bay to Saco Bay, Great Bay, Massachusetts Bay to Cape Cod Bay, Buzzards Bay to Connecticut R., Hudson R./Raritan Bay, Delaware Bay, and Chesapeake Bay 

10-130

Bottom habitats in depressions with a substrate of sand and mud 

M M L L L 

Spawning adults 

GOM, southern edge of GB, continental shelf off SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Sheepscot R., Massachusetts Bay, Cape Cod Bay, Buzzards Bay, and Narragansett Bay 

<100 

May to November, peaks in June and July 

Bottom habitats in depressions with a substrate of sand and mud 

M M L L L 

Rationale: Red hake (Urophycis chuss) is a demersal species that ranges from southern Newfoundland to North Carolina, and is most abundant between GB and New Jersey (Steimle, Morse, Berrien, and Johnson 1999). They occur at depths between 35-980 m, and are most common between 72-124 m (Klein-MacPhee 2002a). Larvae, juveniles, and adults have been found in estuaries from Maine south to Chesapeake Bay (NEFMC 1998). Eggs and larvae are pelagic, and EFH vulnerability to bottom-tending fishing gear is not applicable. Juvenile red hake are found in live sea scallops or empty scallop shells, and are associated with other objects such as other shells, sponges, and rocks (Klein-MacPhee 2002a). Shelter appears to be a critical habitat requirement for this life stage (Able and Fahay 1998), and physical complexity, including biogenic structure other than scallop shells, may be important (Auster et al. 1991, 1995). Their diet consists mainly of amphipods and other infauna and epifauna. Juvenile red hake EFH is considered highly vulnerable to all three mobile gear groups. Adult red hake feed mainly on euphausiids, and consume other invertebrates and fish (Klein-MacPhee 2002a). They are found mainly on soft bottoms (sand and mud) where they create depressions or use existing depressions. They are also found on shell beds, but not on open, sandy bottom. Otter trawls and scallop dredges operate in these soft bottom and shell bed areas and have been shown to affect the structural components of these habitats. Offshore in Maryland and northern Virginia, adult red hake are found on temperate reefs and hard-bottom areas. There is a potential that otter trawls could operate in hard-bottom areas and adversely affect the functional value of these reef habitats. Vulnerability of red hake EFH to otter trawls and scallop dredges was assessed as moderate. Clam dredges would not typically operate in these hard-bottom areas, or in the softer sediments with which red hake are usually associated in the northern extent of their range, but there is some overlap between adult EFH and clam dredge use in sandy habitats. EFH vulnerability to clam dredges was characterized as low. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 154

Table 6.29. Redfish EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic Clam

Dredge

Pots and 

Traps

Sink Gill 

Nets and Bottom

Longlines

Eggs Viviparous (eggs are retained in mother, released as larvae) NA NA NA NA NA Larvae GOM and southern GB 50-270 March to October, peak in August Pelagic waters NA NA NA NA NA Juveniles GOM and southern edge of GB 25-400 

Bottom habitats with a substrate of silt, mud, or hardbottom H H 0 L L 

Adults GOM and southern edge of GB 50-350 

Bottom habitats with a substrate of silt, mud, or hardbottom M M 0 L L 

Spawning adults GOM and southern edge of GB 5-350 April to August 

Bottom habitats with a substrate of silt, mud, or hardbottom M M 0 L L 

Rationale: There are four species of redfish in the Northeast Region. They are Sebastes fasciatus (Acadian redfish), S. mentella (deepwater redfish), S. norvegicus (golden redfish), and Helicolenusdactylopterus (blackbelly rosefish). These four species are difficult to discriminate at all life stages, hence they are usually combined (Pikanowski et al. 1999). Acadian redfish range from Iceland to New Jersey, and deepwater redfish occur from the GOM north. Where the species overlap, the deepwater redfish occurs in deeper water. They range in depth from 25-592 m (Klein-MacPhee and Collette 2002b), with adults most common from 125-200 m, and juveniles from 75 to 175 m (Pikanowski et al. 1999). In general, information about redfish is very limited. Females bear live young and larvae are pelagic, so habitat vulnerability is not applicable to eggs or larvae. Redfish are found chiefly on silt, mud, or hard-bottom and rarely over sand (Pikanowski et al. 1999). On the Scotian Shelf, they are strongly associated with a fine-grained, silt-clay bottom (Klein-MacPhee and Collette 2002b), as well as with deposits of gravel and boulders (Pikanowski et al. 1999). It is hypothesized that redfish do not prefer a particular bottom type, but may be more exposed to predation over a featureless bottom due to their sedentary nature. There is limited evidence that juveniles use anemones and boulders for cover (Pikanowski et al. 1999). Early demersal-phase Acadian redfish have been observed to occur primarily in piled boulder habitats, while late-juvenile redfish occur in both piled boulder, gravel, and dense cerianthid anemone habitats (Auster, Lindholm, and Valentine 2003). Acadian redfish have also been observed in association with deepwater corals and sponges in the GOM (Auster 2005). Habitat vulnerability from otter trawls and scallop dredges in boulder habitats is high since gear can overturn boulders and reduce the number of crevices, as well as dislodge cerianthid anemones from the bottom. Redfish are benthic during the day, and become more active at night when they rise off the bottom, following the vertical migration of their primary euphausiid prey (Pikanowski et al. 1999). They also eat some benthic fish. Adult EFH was determined to be moderately vulnerable to impacts from otter trawls and scallop dredges. Clam dredges do not operate in areas of redfish EFH, so vulnerability was rated as none. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 155

Table 6.30. Rosette skate EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Juveniles 

Nantucket Shoals and southern edge of GB to Cape Hatteras 

33-530, 

mostly 74-

274 

Bottom habitats with soft substrate, including sand/mud bottoms, mud with echinoid and ophiuroid fragments, and shell and pteropod ooze 

M M M L L 

Adults 

Nantucket Shoals and southern edge of GB to Cape Hatteras 

33-530, 

mostly 74-

274 

Bottom habitats with soft substrate, including sand/mud bottoms, mud with echinoid and ophiuroid fragments, and shell and pteropod ooze 

M M M L L 

Rationale: Rosette skate (Leucoraja garmani virginica) is a deeper water species that occurs along the outer shelf and continental slope from Nantucket Shoals to the Dry Tortugas, Florida. North of Cape Hatteras, it is most abundant in the southern section of the Chesapeake Bight. It occurs on soft bottoms, including sand and mud, at depths from 33-530 m, and is most common between 74-274 m (Packer et al. 2003d). Major prey items include polychaetes, copepods, cumaceans, amphipods, Crangon, crabs, squid, octopods, and small fishes. A single fertilized egg is encapsulated in a leathery case. Egg cases are found in mature females most frequently in the summer (Packer et al. 2003d). Information on rosette skate is very limited. Because of the limited information available, the apparent dependence of the juveniles of this species on benthic organisms in its diet, and the reproductive habits of the adults, EFH vulnerability to mobile bottom gear was characterized as moderate. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 156

Table 6.31. Scup EFH-vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

SNE to coastal Virginia, including the following estuaries: Waquoit Bay to Long Island Sound, Gardiners Bay, and Hudson R./Raritan Bay 

(<30) May to August Pelagic waters in estuaries NA NA NA NA NA 

Larvae 

SNE to coastal Virginia, including the following estuaries: Waquoit Bay to Long Island Sound, Gardiners Bay, and Hudson R./Raritan Bay 

(<20) May to September Pelagic waters in estuaries NA NA NA NA NA 

Juveniles 

Continental shelf from GOM to Cape Hatteras, including the following estuaries: Massachusetts Bay, Cape Cod Bay to Long Island Sound, Gardiners Bay to Delaware inland bays, and Chesapeake Bay 

(0-38) Spring and summer in estuaries and bays 

Demersal waters north of Cape Hatteras; inshore on various sand, mud, mussel, and eelgrass bed substrates 

M M M L L 

Adults 

Continental shelf from GOM to Cape Hatteras, including the following estuaries: Cape Cod Bay to Long Island Sound, Gardiners Bay to Hudson R./Raritan Bay, Delaware Bay, Delaware inland bays, and Chesapeake Bay 

(2-

185) 

Wintering adults (November to April) are usually offshore, south of New York to North Carolina 

Demersal waters north of Cape Hatteras; inshore estuaries on various substrate types 

L L L L L 

Rationale: Scup (Stenotomus chrysops) is a temperate species that occurs primarily from Massachusetts to South Carolina, although it has been reported as far north as the Bay of Fundy and Sable Island Bank (Steimle, Zetlin, Berrien, Johnson, and Chang 1999a). Scup are primarily benthic feeders that use a variety of habitat types. Juveniles forage on epibenthic amphipods, other small crustaceans, polychaetes, mollusks, and fish eggs and larvae. They occur over a variety of substrates, and are most abundant in areas without structure. Limited observations of scup have shown periodic use of seafloor depressions for cover (Auster et al. 1991, 1995). Adults are found on soft bottoms or near structures. During the summer, they are closer inshore and are found on a wider range of habitats. In the winter, they congregate offshore in areas that are expected to serve as a thermal refuge (Klein-McPhee 2002c), particularly in deeper waters of the outer continental shelf and around canyon heads. Smaller adults feed on echinoderms, annelids, and small crustaceans. Larger scup consume more squids and fishes. Since juvenile scup are primarily benthic feeders, their EFH was rated as moderately vulnerable to impacts from mobile bottom gear. EFH vulnerability for adults was rated as low since there is less of a reliance on benthic prey items. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 157

Table 6.32 Sea scallop EFH -- vulnerability to effects of bottom-tending fishing and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GOM, GB, SNE, middle Atlantic south to Virginia-North Carolina border, and the following estuaries: Passamaquoddy Bay to Sheepscot R., Casco Bay, Massachusetts Bay, and Cape Cod Bay 

May through October, peaks in May and June in middle Atlantic area, and in Sept. and Oct. on GB and in GOM 

Bottom habitats L L L L L Pelagic waters NA NA NA NA NA 

Larvae 

GOM, GB, SNE, middle Atlantic south to Virginia-North Carolina border, and the following estuaries: Passamaquoddy Bay to Sheepscot R., Casco Bay, Massachusetts Bay, and Cape Cod Bay 

Bottom habitats with a substrate of gravelly sand, shell fragments, pebbles, or on various red algae, hydroids, amphipod tubes, and bryozoans 

L L L L L 

Juveniles 

GOM, GB, SNE, middle Atlantic south to Virginia-North Carolina border, and the following estuaries: Passamaquoddy Bay to Sheepscot R., Casco Bay, Great Bay, Massachusetts Bay, and Cape Cod Bay 

18-110 Bottom habitats with a substrate of 

cobble, shells, and silt 

L L L L L 

Adults 

GOM, GB, SNE, middle Atlantic south to Virginia-North Carolina border, and the following estuaries: Passamaquoddy Bay to Sheepscot R., Casco Bay, Great Bay, Massachusetts Bay, and Cape Cod Bay 

18-110 Bottom habitats with a substrate of 

cobble, shells, coarse/gravelly sand, and sand 

L L L L L 

Spawning adults 

GOM, GB, SNE middle Atlantic south to Virginia-North Carolina border, and the following estuaries: Passamaquoddy Bay to Sheepscot R., Casco Bay, Massachusetts Bay, and Cape Cod Bay 

18-110 May through October, peaks 

in May and June in middle Atlantic area, and in Sept. and Oct. on GB and in GOM 

Bottom habitats with a substrate of cobble, shells, coarse/gravelly sand, and sand 

L L L L L 

Rationale: Juvenile and adult sea scallops (Placopecten magellanicus) are found on the continental shelf of the Northwest Atlantic, from the Gulf of St. Lawrence south to Cape Hatteras, typicallybetween 18 and 110 m, but also as shallow as 2 m in estuaries and embayments along the Maine coast, and as deep as 384 m (Packer, Cargnelli, et al. 1999). In the GOM, populations have been reported at depths of 170-180 m. Scallops are rarely found at depths <55 m in “southern areas.” Scallop eggs are slightly heavier than seawater and are thought to remain on the bottom during development, but bottom habitats have no known functional value for eggs, and therefore, their vulnerability to fishing was rated as low for all gear types. There are four pelagic larval stages, and EFH vulnerability to fishing gear impacts for these larval stages is not applicable. However, the last larval stage is benthic; at this stage, larvae settle to the bottom (as “spat”) and attach to hard surfaces (Packer, Cargnelli, et al. 1999). Settlement occurs in areas of gravelly sand with shell fragments. Spat are very delicate and do not survive on shifting sand bottoms. The availability of suitable surfaces on which to settle appears to be a primary requirement for successful reproduction (Packer, Cargnelli, et al. 1999). There is a close association between the bryozoan Eucratea loricata and spat. Eucratea attach to adult scallops, and have been found to contain large numbers of spat. EFH for benthic-phase larvae was given a low rating for vulnerability to all three mobile gear types because any disturbance of the bottom they would cause would most likely redistribute bottom sediments suitable for settlement (gravel, pebbles, shell fragments), but not reduce their availability. Juveniles are found mainly on gravel, small rocks, shells, and silt. During their second growing season (5-12 mm), sea scallops become mobile and leave the original substrate on which they settled, and then re-
Page 158

Table 6.32 Sea scallop EFH -- vulnerability to effects of bottom-tending fishing and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

attach to shells and bottom debris. Otter trawls, scallop dredges, and hydraulic clam dredges are used in bottom habitats occupied by juvenile scallops, but the disturbance of the seafloor caused by these gears does not adversely affect the functional value of the habitat and, therefore, the vulnerability of juvenile scallop EFH to mobile benthic gears was rated as low. The same conclusion was reached for fixed gear which cause negligible disturbance to the seafloor. Juveniles and adults are found in benthic habitats with at least some water movement, which is critical for feeding, oxygen and removal of waste; optimal growth for adults occurs at 10 cm/sec (Packer, Cargnelli, et al. 1999). Adult scallops inhabit coarse substrates, usually gravel, shell, and rock. Because fine clay particles interfere withfeeding activity, scallops are not usually found on muddy bottom. No scientific information exists that indicates mobile fishing gears have a negative impact on the functional value of adult scallop EFH. The vulnerability of adult scallop EFH to mobile benthic gears was therefore rated as low. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 159

Table 6.33. Silver hake EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GOM, GB, continental shelf off SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Merrimack R. to Cape Cod Bay 

50–150 All year, peaks June to October Surface waters NA NA NA NA NA 

Larvae 

GOM, GB, continental shelf off SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Massachusetts Bay to Cape Cod Bay 

50–130 All year, peaks July to September Surface waters NA NA NA NA NA 

Juveniles 

GOM, GB, continental shelf off SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Passamaquoddy Bay to Casco Bay, and Massachusetts Bay to Cape Cod Bay 

20–270 Bottom habitats of all substrate types M M M L L 

Adults 

GOM, GB, continental shelf off SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Passamaquoddy Bay to Casco Bay, and Massachusetts Bay to Cape Cod Bay 

30–325 Bottom habitats of all substrate types L L L L L 

Spawning adults 

GOM, GB, continental shelf off SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Massachusetts Bay and Cape Cod Bay 

30–325 Bottom habitats of all substrate types L L L L L 

Rationale: Silver hake or whiting (Merluccius bilinearis) range from Newfoundland south to Cape Fear, NC, and are most common from Nova Scotia to New Jersey (Morse et al. 1999). They are distributed broadly, and are found from nearshore shallows out to a depth of 400 m (Klein-MacPhee 2002f). All life stages have been found in estuaries from Maine to Cape Cod Bay (Morse et al. 1999). The vertical movement of silver hake is governed chiefly by their pursuit of prey; both juveniles and adults show a vertical migration off the bottom at night when feeding activity is greatest. In the Mid-Atlantic Bight, juvenile silver hake have been found in greater densities in areas with greater amphipod tube cover (Auster et al. 1997). Further, silver hake size distributions in sand wave habitats are positively correlated with sand wave period (i.e., the spacing between sand waves), suggesting energetic or prey capture benefits in particular sand wave environments (Auster, Lindholm, Schaub, et al. 2003). Juveniles are primarily found on silt or sand substrate, and feed mainly on crustaceans, including copepods, amphipods, euphausiids, and decapod crustaceans (Morse et al. 1999). The vulnerability of juvenile EFH to mobile gear was rated as moderate because of the potential connection between structure and habitat suitability for this life stage. Adult silver hake rest on the bottom in depressions by day, primarily over sand and pebble bottoms, and rarely in rockier areas. In the Mid-Atlantic Bight, adults were found on flat sand, sand wave crests, shell, and biogenic depressions, but were most often found on flat sand. At night, adults feed on anchovies, herring, lanternfish, and other fishes (Klein-MacPhee 2002f). Piscivory increases with size for this species. Vulnerability of adult silver hake EFH to the three mobile gear types was rated as low because of silver hake’s piscivorous food habits and preference for higher energy sand environments which recover quickly from fishing gear impacts (see Chapter 5 of this document). Eggs and larvae of this species are pelagic, so habitat vulnerability to fishing gear is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 160

Table 6.34. Smooth skate EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic Clam

Dredge

Pots and

Traps

Sink Gill 

Nets and Bottom

Longlines

Juveniles Offshore banks of GOM 31–874, mostly 110- 457 Bottom habitats with a substrate of soft mud (silt and clay), sand, broken shells, gravel, and pebbles M M 0 L L Adults Offshore banks of GOM 31–874, mostly 110- 457 Bottom habitats with a substrate of soft mud (silt and clay), sand, broken shells, gravel, and pebbles H H 0 L L Rationale: Smooth skate’s (Malacoraja senta) center of abundance is the GOM. It occurs along the Atlantic coast from the Gulf of St. Lawrence south to South Carolina, at depths between 31-874 m (Packer et al. 2003e). It is most abundant between 110-457 m. Analysis of NEFSC trawl survey data found juvenile skate most abundant between depths of 100 -300 m during 1963-1969. Smooth skate are found mostly over soft mud and clay of the GOM’s deepwater basins, but also over the gulf’s offshore banks with substrates of sand, shell, and/or gravel (Packer et al. 2003e). The diet of smooth skate is generally limited to epifaunal crustaceans, with decapod shrimp and euphausids as the most common prey, followed by amphipods and mysids. The diet shifts from amphipods and mysids to decapod crustaceans as smooth skate grow (Packer et al. 2003e). The diet of smooth skate is more restricted than that of other skate species (McEachran 2002). The vulnerability of juvenile smooth skate EFH to otter trawls and scallop dredges was characterized as moderate because of the dietary habits of this species. The vulnerability of adult EFH was rated as high for otter trawls and scallop dredges because of the benthic diet as well as the reproductive habits of the species. Vulnerability to clam dredges was considered to be none for juveniles and adults since this gear is not used in the GOM. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 

Table 6.35 Spanish mackerel EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage

Geographic Area of

EFHa

Depth

(m)

Seasonal

Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

All life stages 

South Atlantic and Mid-Atlantic Bights 

Sandy shoals of capes and offshore bars; high-profile rock bottoms and barrier island oceanside waters from surf zone to shelf break, but from the Gulf Stream shoreward 

NA NA NA NA NA 

Rationale: All life stages of Spanish mackerel (Scomberomorus maculatus) are pelagic, so their EFH is not vulnerable to bottom-tending fishing gear, and vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 161

Table 6.36. Spiny dogfish EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Juveniles 

Across the continental shelf from GOM to Cape Hatteras, and south of Cape Hatteras through Florida; also includes the following estuaries: Passamaquaddy Bay to Saco Bay; Massachusetts Bay, and Cape Cod Bay 

10-390 

Continental shelf waters and estuaries 

L L L L L 

Adults 

Across the continental shelf from GOM to Cape Hatteras, and south of Cape Hatteras through Florida; also includes following estuaries: Passamaquaddy Bay to Saco Bay, Massachusetts Bay, and Cape Cod Bay 

10-450 

Continental shelf waters and estuaries 

L L L L L 

Rationale: The spiny dogfish (Squalus acanthias) is a coastal shark with a circumboreal distribution, and is one of the most abundant sharks in the western North Atlantic (McMillan and Morse 1999). Female dogfish are viviparous, so EFH designations were limited to juveniles and adults. Smaller dogfish have been reported to feed primarily on crustaceans, with an increase in piscivory in larger individuals (Burgess 2002). Fish, mainly schooling pelagic species, constitute 50% of their diet. Their voracious and opportunistic feeding behavior was emphasized by McMillan and Morse (1999). Since neither of these life stages appears to be closely tied to benthic organisms, the vulnerability of their EFH to mobile gear was rated as low. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 162

Table 6.37. Summer flounder EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs Over continental shelf from GOM to Florida 

30-70 in 

fall; 110 in 

winter; 9-

30 in 

spring 

October to May 

Pelagic waters; heaviest concentrations within 9 mi of shore off New Jersey and New York 

NA NA NA NA NA 

Larvae 

Over continental shelf from GOM to Florida; also includes the following estuaries: Waquoit Bay to Narragansett Bay, Hudson R./Raritan Bay, Barnegat Bay, Chesapeake Bay, Rappahannock R., York R., James R., Albemarle Sound, Pamlico Sound, and Neuse R. to Indian R. 

10-70 

Mid-Atlantic Bight from September to February; southern part of range from November to May at depths of 9-30 m 

Pelagic waters; larvae most abundant 19-83 km from shore NA NA NA NA NA 

HAPC H 0 0 NA NA 

Juveniles 

Over continental shelf from GOM to Florida; also includes the following estuaries: Waquoit Bay to James R., and Albemarle Sound to Indian R. 

0.5–5 in 

estuary 

Demersal waters, on muddy substrate but prefer mostly sand; found in the lower estuaries in flats, channels, salt marsh creeks, and eelgrass beds 

NonHAPC L L L 0 0 HAPC H 0 0 NA NA 

Adults 

Over continental shelf from GOM to Florida; also includes the following estuaries: Buzzards Bay, Narragansett Bay, Connecticut R. to James R., Albemarle Sound to Broad R.; St. Johns R., and Indian R. 

0-25 

Shallow coastal and estuarine waters during warmer months; move offshore on outer continental shelf at depths of 150 m in colder months 

Demersal waters and estuaries NonHAPC L L L 0 0 

Rationale: Summer flounder (Paralichthys dentatus) occur in the shallow estuarine waters and outer continental shelf from Nova Scotia to Florida, with the center of their range located in the MidAtlantic Bight (Packer, Griesbach, et al. 1999). Juvenile summer flounder are opportunistic feeders, and their diet includes fish, mysids, and some other crustaceans (Packer, Griesbach, et al. 1999). There are gradual changes in the diet of summer flounder, with fish becoming more important as a food source as individuals get older and larger. Adults are also opportunistic feeders, with fish and crustaceans making up a significant portion of their diet. Eelgrass and macroalgae beds have been designated as habitat areas of particular concern (HAPC) for adult and juvenile summer flounder. Stephan et al. (2000) determined that otter trawls could result in below-ground impacts to submerged aquatic vegetation (SAV), which, of all the impacts to SAV possible from fishing gear, was ranked as the impact of greatest concern. Based on potential impacts to SAV, the vulnerability of the summer flounder HAPC to otter trawls was rated as high. Sea scallop and surfclam/quahog dredges are not used in estuaries where SAV is found. Fixed, bottom-tending gears, such as pots, traps, and sink gillnets, may be used in inshore SAV beds, but if so, their use is not federally-regulated. Thus, the vulnerability of juvenile and adult HAPCs to the effects of these gear types is not applicable. Since adults and juveniles are both opportunistic feeders, the vulnerability of EFH that is not designated as HAPC was rated as low for bottom trawls and dredges. Summer flounder eggs and larvae are pelagic, so EFH vulnerability is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 163

Table 6.38. Thorny skate EFH--vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic Clam

Dredge

Pots and 

Traps

Sink Gill 

Nets and Bottom

Longlines

Juveniles GOM and GB 

18-2000, 

mostly 111-

366 

Bottom habitats with a substrate of sand, gravel, broken shell, pebbles, and soft mud 

M M 0 L L 

Adults GOM and GB 

18-2000, 

mostly 111-

366 

Bottom habitats with a substrate of sand, gravel, broken shell, pebbles, and soft mud 

M M 0 L L 

Rationale: Thorny skate (Amblyraja radiata) range from Greenland south to South Carolina. In the Northeast Region, this species is most commonly seen in the GOM and on the Northeast Peak and in the northern portion of the Great South Channel of GB. It is one of the most common skates in the GOM, and occurs over a wide variety of bottom substrates, including sand, gravel, and broken shell to mud (Packer et al. 2003f). It is found at depths ranging from 18-1200 m, and is reported to be most common between 50-350 m. A single fertilized egg is encapsulated in an egg case. Females with fully formed egg cases have been captured year-round, though the percentage of mature females with egg cases is higher in the summer (Packer et al. 2003f). The primary prey of thorny skates are polychaetes and decapod crustaceans, followed by amphipods and euphausiids. Fish and mysids are also consumed in lesser quantities. According to a survey from Nova Scotia to Cape Hatteras, thorny skate prey varies with skate size. Skates less than 40 cm total length feed mostly on amphipods, skates greater than 40 cm fed on polychaetes and decapod crustaceans, and fishes were a major dietary component for skates larger than 70 cm. In general, with increasing size, mysids decreased in the diet while fishes increased (Packer et al. 2003f). Since juvenile thorny skate appear to be more reliant on benthic invertebrates, vulnerability of EFH to otter trawls and scallop dredges for this life stage was characterized as moderate. For adults, EFH vulnerability to otter trawls and scallop dredges was characterized as moderate because of their reproductive habits. EFH vulnerability to clam dredges was rated as none for juveniles and adults since there is no overlap between thorny skate EFH and areas in which clam dredges are used. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 164

Table 6.39. Tilefish EFH--vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam Dredge 

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

U.S./Canadian boundary to Virginia/North Carolina boundary (shelf break: GB to Cape Hatteras) 

76-365 

Serial spawning from March to November; peaks during April to October 

Water column NA NA NA NA NA 

Larvae 

U.S./Canadian boundary to Virginia/North Carolina boundary (outer continental shelf: GB to Cape Hatteras) 

76-365 February to October; peaks during July to October Water column NA NA NA NA NA 

Juveniles 

U.S./Canadian boundary to Virginia/North Carolina boundary (shelf break, submarine canyon walls, and flanks: GB to Cape Hatteras) 

76-365 All year; may leave GB in winter Rough bottom, small burrows, and sheltered areas; substrate rocky, stiff clay, human debris H L 0 L L 

Adults 

U.S./Canadian boundary to Virginia/North Carolina boundary (shelf break, submarine canyon walls, and flanks: GB to Cape Hatteras) 

76-365 All year; may leave GB in winter Rough bottom, small burrows, and sheltered areas; substrate rocky, stiff clay, human debris H L 0 L L 

Rationale: Tilefish (Lopholatilus chamaeleonticeps) are restricted to the continental shelf break south of the Gulf of Maine (Steimle, Berrien, Johnson and Chang 1999). They occupy a number of habitats, including scour basins around rocks or other rough bottom areas that form burrow-like cavities, and pueblo habitats in clay substrate. The dominant habitat type is a vertical burrow in a substrate of semi-hard silt-clay, 2 - 3 m deep and 4 - 5 m in diameter with a funnel shape. These burrows are excavated by tilefish, secondary burrows are created by other organisms, including lobsters, conger eels, and galatheid crabs. Tilefish are visual daytime feeders on galatheid crabs, mollusks, shrimps, polychaetes, and occasionally fish. Mollusks and echinoderms are more important to smaller tilefish. Little is known about juveniles of the species. A report to the Mid-Atlantic Fishery Management Council (Able and Muzeni 2002), based upon a review of archived video surveys in areas of tilefish habitat, did not find visual evidence of direct impacts to burrows due to otter trawls. The Northeast Region EFH Steering Committee Workshop (NREFHSC 2002) concluded that there was the potential for a high degree of impact to the physical structure of hard clay outcroppings (pueblo village habitat) by trawls that would result in permanent change to a major physical feature which provides shelter for tilefish as well as their benthic prey. Although Able and Muzeni’s (2002) review did not offer any evidence of this type of negative effect, their sample size for this habitat type was very small. Due to the tilefish’s reliance on structured shelter and benthic prey, as well as the benthic prey’s reliance on much of the same habitat, and the need for further study, the vulnerability of tilefish EFH to otter trawls was ranked as high. Clam dredges operate in shallow, sandy waters typically uninhabited by tilefish, so EFH vulnerability was rated as none for this gear. Scallop vessel monitoring data (Section 4) indicate that scallop dredges operate to a small extent in areas overlapping tilefish EFH; therefore, EFH vulnerability to scallop dredges was ranked as low. Tilefish eggs and larvae are pelagic; therefore, EFH vulnerability is not applicable.a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 165

Table 6.40. White hake EFH-vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs GOM, GB, SNE, and the following estuaries: Great Bay to Cape Cod Bay August to September Surface waters NA NA NA NA NA Larvae 

GOM, southern edge of GB, SNE to middle Atlantic, and the following estuaries: Massachusetts Bay to Cape Cod Bay 

May in mid-Atlantic area, August and September in GOM, GB area 

Pelagic waters NA NA NA NA NA 

Juveniles 

GOM, southern edge of GB, SNE to middle Atlantic, and the following estuaries: Passamaquoddy Bay to Great Bay, and Massachusetts Bay to Cape Cod Bay 

5-225 May to September 

Pelagic stage--pelagic waters; demersal stage--bottom habitat with seagrass beds or substrate of mud or fine-grained sand 

M M 0 L L 

Adults 

GOM, southern edge of GB, SNE to middle Atlantic, and the following estuaries: Passamaquoddy Bay to Great Bay, and Massachusetts Bay to Cape Cod Bay 

5-325 Bottom habitats with substrate of mud or fine-grained sand L L 0 L L 

Spawning adults 

GOM, southern edge of GB, SNE to middle Atlantic 5-325 

April to May, southern part of range; August to September, northern part of range 

Bottom habitats with substrate of mud or fine-grained sand in deepwater 

L L 0 L L 

Rationale: White hake (Urophycis tenuis) adults co-occur geographically with red hake, and their habits are similar, but white hake are distributed in a wider range of depths and temperatures (Chang, Morse, et al. 1999; Klein-MacPhee 2002a). They are found from Labrador south to North Carolina, and occasionally stray as far as Florida and Iceland. They inhabit coastal estuaries and occur across the continental shelf to the submarine canyons along the upper continental shelf, and in the basins of the GOM. Adult distribution in the region is focused in the GOM and along the southern slope of Georges Bank. All life stages are found in estuaries near the GOM (NEFMC 1998). Most pelagic juveniles cross the shelf and enter estuaries from Canada south to the Mid-Atlantic Bight, although some may also settle to the bottom in unknown shelf habitats (Klein-MacPhee 2002a). Demersal juveniles are found in nearshore waters out to a depth of about 225 m (Chang, Morse, et al. 1999). Eelgrass is an important habitat for juveniles, but its functional importance is unknown; this life stage is not necessarily dependent upon structure (Able and Fahay 1998). Young-of-the-year white hake feed mainly on shrimp, mysids, and amphipods. Since otter trawls and scallop dredges can negatively impact eelgrass (Stephan et al. 2000) in estuaries, vulnerability of juvenile white hake EFH to these gears was characterized as moderate. Hydraulic clam dredges are not utilized in estuaries of the GOM, so vulnerability to this gear was rated as none. Adults prefer benthic deposits of fine-grained sediments (Chang, Morse, et al. 1999). They feed primarily on fish, cephalopods, and crustaceans. Since they are not benthivores and have not been documented to use benthic habitats for cover, EFH vulnerability to otter trawls and scallop dredges was characterized as low. Clam dredges are not operated in areas of adult EFH, and vulnerability to this gear was rated as none. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 166

Table 6.41. Windowpane EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam

Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GOM, GB, SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Passamaquoddy Bay to Great Bay, and Massachusetts Bay to Delaware inland bays 

<70 

February to November, peaks May and October in middle Atlantic, July to August on GB 

Surface waters NA NA NA NA NA 

Larvae 

GOM, GB, SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Passamaquoddy Bay to Great Bay, and Massachusetts Bay to Delaware inland bays 

<70 

February to November, peaks May and October in middle Atlantic, July to August on GB 

Pelagic waters NA NA NA NA NA 

Juveniles 

GOM, GB, SNE, middle Atlantic south to Cape Hatteras, and the following estuaries: Passamaquoddy Bay to Great Bay, and Massachusetts Bay to Chesapeake Bay 

1-100 

Bottom habitats with substrate of mud or fine-grained sand 

L L L L L 

Adults 

GOM, GB, SNE, middle Atlantic south to Virginia/North Carolina border, and the following estuaries: Passamaquoddy Bay to Great Bay, and Massachusetts Bay to Chesapeake Bay 

1-75 

Bottom habitats with substrate of mud or fine-grained sand 

L L L L L 

Spawning adults 

GOM, GB, SNE, middle Atlantic south to Virginia/North Carolina border, and the following estuaries: Passamaquoddy Bay to Great Bay, and Massachusetts Bay to Delaware inland bays 

1-75 February to December, peak in May in middle Atlantic Bottom habitats with substrate of mud or fine-grained sand L L L L L 

Rationale: Windowpane flounder (Scophthalmus aquosus) is distributed in coastal waters from the Gulf of St. Lawrence to Florida, and are most abundant on GB and in the New York Bight (KleinMacPhee 2002b). Windowpane are abundant in estuaries from Maine through Chesapeake Bay (NEFMC 1998). They are a shoal-water fish, with a depth range of up to 200 m, but are most abundant in waters less than 50 m deep. Both juveniles and adults are found on muddy sediments in the GOM, and fine, sandy sediments on GB and in New England and the Mid-Atlantic Bight. Mysids are the main prey item of juveniles (Klein-MacPhee 2002b). Adults have been shown to feed exclusively on nekton and show little need for bottom structure (Chang, Berrien, Johnson, and Morse 1999). EFH vulnerability to the three types of mobile gear was rated as low for both these life stages. Windowpane eggs and larvae are pelagic, so EFH vulnerability to fishing gear is not applicable for these two life stages. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 167

Table 6.42. Winter flounder EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam Dredge 

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GB, inshore areas of GOM, SNE, middle Atlantic south to Delaware Bay and the following estuaries: Passamaquoddy Bay to Delaware inland bays 

<5 February to June, peak in April on GB Bottom habitats with a substrate of sand, muddy sand, mud, and gravel L L L L L 

Larvae 

GB, inshore areas of GOM, SNE, middle Atlantic south to Delaware Bay and the following estuaries: Passamaquoddy Bay to Delaware inland bays 

 <6 

March to July, peak in April and May on GB 

Pelagic and bottom waters L L L L L 

Juveniles 

GB, inshore areas of GOM, SNE, middle Atlantic south to Delaware Bay and the following estuaries: Passamaquoddy Bay to Chincoteague Bay 

0.1–10 (1-

50, age 

1+) 

Bottom habitats with a substrate of mud or finegrained sand L L L L L 

Adults 

GB, inshore areas of GOM, SNE, middle Atlantic south to Delaware Bay and the following estuaries: Passamaquoddy Bay to Chincoteague Bay 

1-100 

Bottom habitats including estuaries with substrates of mud, sand, gravel 

M M M L L 

Spawning adults 

GB, inshore areas of GOM, SNE, middle Atlantic south to Delaware Bay and the following estuaries: Passamaquoddy Bay to Delaware inland bays 

<6 February to June 

Bottom habitats including estuaries with substrates of mud, sand, gravel 

M M M L L 

Rationale: Winter flounder (Pseudopleuronectes americanus) range from Labrador to Georgia, and are most abundant from the Gulf of St. Lawrence to Chesapeake Bay (Klein-MacPhee 2002d). Juveniles and adults are found in waters less than 100 m deep, and most are found from shore to 30 m. They range far upstream in estuaries, and have been found in freshwater. Winter flounder lay demersal adhesive eggs in shallow water less than 5 m in depth, with the exception of spawning areas on GB and Nantucket shoals (Pereira et al. 1999). Substrates include sand, muddy sand, mud, and gravel, with sand the most common. Although otter trawls, scallop dredges, and clam dredges may affect the eggs directly, this was not considered a habitat impact. Since there is no indication that the eggs rely on any structure, egg EFH vulnerability to these three gears was rated as low. Since early stage larvae are associated with the bottom and are at times demersal (Able and Fahay 1998), larval EFH vulnerability to all gears was also rated as low instead of none. Juvenile and adult winter flounder are found on mud and sand substrates, and adults are seen on cobble, rocks, and boulders (Pereira et al. 1999). Both life stages can be opportunistic feeders, however, their main prey items are infaunal invertebrates. Because of their reliance on infauna and their ability to use alternative food supplies, EFH vulnerability to the three mobile gear types for these life stages was ranked as moderate. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 168

Table 6.43. Winter skate EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life

Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

ScallopDredge

Hydraulic

Clam Dredge 

Pots and 

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Juveniles 

Cape Cod Bay, GB, SNE shelf through MidAtlantic Bight to North Carolina; includes estuaries from Buzzards Bay south to Chesapeake Bay 

0-37, 

mostly 

<111 

Bottom habitats with substrate of sand and gravel or mud 

M M M L L 

Adults 

Cape Cod Bay, GB SNE shelf through Mid-Atlantic Bight to North Carolina; includes estuaries from Buzzards Bay south to Chesapeake Bay 

0-371, 

mostly 

<111 

Bottom habitats with substrate of sand and gravel or mud 

M M M L L 

Rationale: Winter skate (Leucoraja ocellata) are found from Newfoundland south to Cape Hatteras. They are most abundant on GB and in coastal waters south to the mouth of the Hudson River. They are found over substrates of sand, gravel, and mud, in depths from shore out to 371 m, and are most common in <111 m of water (Packer et al. 2003g). Females deposit single fertilized eggs in egg capsules, which are deposited on the bottom during summer in the northern portion of the range. Deposition has been reported to extend through January off SNE. Young are fully developed at hatching (Packer et al. 2003g). Polychaetes and amphipods are the most important prey items, followed by decapod crustaceans, isopods, bivalves, and fish. In general, crustaceans make up over 50% of the diet for skate smaller than 61 cm, and fish and bivalves are a major component of the diet for skates larger than 79 cm (Packer et al. 2003g). Crustaceans generally declined in importance with increasing skate size, while polychaetes increased, until skates reached 81 cm. Since juvenile winter skate appear to be more reliant on benthic invertebrates, vulnerability of EFH to mobile gear for this life stage was characterized as moderate. For adults, EFH vulnerability to mobile gear was characterized as moderate because of their reproductive habits. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 169

Table 6.44. Witch flounder EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic Clam

Dredge

Pots and 

Traps

Sink Gill 

Nets and Bottom

Longlines

Eggs 

GOM, GB, continental shelf off SNE, and middle Atlantic south to Cape Hatteras 

Deep March to October Surface waters NA NA NA NA NA 

Larvae 

GOM, GB, continental shelf off SNE, and middle Atlantic south to Cape Hatteras 

Deep March to November, peaks from May to July Surface waters NA NA NA NA NA 

Juveniles GOM and outer continental shelf from GB south to Cape Hatteras 50-450 Bottom habitats with fine-grained substrate M L 0 L L Adults GOM and outer continental shelf from GB south to Chesapeake Bay 25-300 Bottom habitats with fine-grained substrate M L L L L Spawning adults 

GOM and outer continental shelf from GB south to Chesapeake Bay 25-360 

March to November, peaks from May to August 

Bottom habitats with fine-grained substrate M L L L L 

Rationale: Witch flounder (Glyptocephalus cynoglossus) range from Newfoundland south to Cape Hatteras. In U.S. waters, this species is common throughout the GOM, and is found in the deeper areas of and adjacent to GB and along the continental shelf edge and upper slope (Cargnelli, Griesbach, Packer, Berrien, Morse, et al. 1999, Klein-MacPhee 2002d). Juvenile and adult witch flounder are found mainly over fine muddy sand, or mud. Their diet is comprised mainly of polychaetes, and they feed on other invertebrates as well (Cargnelli , Griesbach, Packer, Berrien, Morse, et al. 1999). Since these life stages occur in areas of lower natural disturbance and rely on infauna, EFH vulnerability to impacts from otter trawls were rated as moderate. Impacts from scallop dredging may be less severe, since scallop dredges are not usually used in muddy habitat; however, vessel trip reports indicated scallop dredging in areas of witch flounder EFH (see Chapter 4 of this document). Therefore, vulnerability to scallop dredges was rates as low. Juvenile EFH vulnerability to clam dredges was rated as none since clam dredges are not used in mud or in water depths where juvenile witch flounder are primarily found. However, EFH vulnerability to clam dredges for adults was rated as low since clam dredges do operate in adult EFH. Eggs and larvae of witch flounder are pelagic, so vulnerability of EFH to fishing gear impacts is not applicable. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 170

Table 6.45. Yellowtail flounder EFH -- vulnerability to effects of bottom-tending fishing gears and rationale for evaluations

EFH Vulnerabilityb

Life Stage Geographic Area of EFHa Depth (m) Seasonal Occurrence EFH Description Otter

Trawl

New

BedfordStyle

Scallop

Dredge

Hydraulic

Clam Dredge

Pots

and

Traps

Sink Gill 

Nets and 

Bottom

Longlines

Eggs 

GB, Massachusetts Bay, Cape Cod Bay, SNE continental shelf south to Delaware Bay, and the following estuaries: Passamaquoddy Bay to Saco Bay; Great Bay to Cape Cod Bay 

30-90 Mid-March to July, peaks in April to June in SNE Surface waters NA NA NA NA NA 

Larvae 

GB, Massachusetts Bay, Cape Cod Bay, SNE continental shelf, middle Atlantic south to Chesapeake Bay, and the following estuaries: Passamaquoddy Bay to Cape Cod Bay 

10-90 

March to April in New York Bight; May to July in SNE and southeastern GB 

Surface waters NA NA NA NA NA 

Juveniles 

GB, GOM, SNE continental shelf south to Delaware Bay, and the following estuaries: Sheepscot R., Casco Bay, Massachusetts Bay to Cape Cod Bay 

20-50 

Bottom habitats with substrate of sand or sand and mud 

M M M L L 

Adults 

GB, GOM, SNE continental shelf south to Delaware Bay, and the following estuaries: Sheepscot R., Casco Bay, Massachusetts Bay to Cape Cod Bay 

20-50 

Bottom habitats with substrate of sand or sand and mud 

M M M L L 

Spawning adults 

GB, GOM, SNE continental shelf south to Delaware Bay, and the following estuaries: Massachusetts Bay to Cape Cod Bay 

10-125 

Bottom habitats with substrate of sand or sand and mud 

M M M L L 

Rationale: Yellowtail flounder (Limanda ferruginea) are found from the Gulf of St. Lawrence south to the Chesapeake Bay (Johnson et al. 1999; Klein-MacPhee 2002d). They are most abundant on the western half of GB, western GOM, east of Cape Cod, and off SNE (Johnson et al. 1999). Their usual depth range is from 10-100 m (Klein-MacPhee 2002d). Juveniles and adults are found in some New England estuaries, while eggs and larvae are found more frequently in these habitats (NEFMC 1998). Yellowtail eggs and larvae are pelagic, so EFH vulnerability is not applicable. Yellowtail flounder feed mainly on benthic macrofauna, primarily amphipods and polychaetes (Johnson et al. 1999). Adults eat mostly crustaceans while juveniles focus on polychaetes. Both life stages are found on substrates of sand or sand and mud. Vulnerability of juvenile and adult EFH to the three types of mobile gear was rated as moderate because of the potential effect of these gears on infaunal yellowtail prey. a EFH Geographic Areas: GOM = Gulf of Maine; GB = Georges Bank; and SNE = Southern New England. b EFH Vulnerability Category (derived from the matrix analysis in Table 6.1): NA = not applicable; 0 = no vulnerability; L = low vulnerability; M = moderate vulnerability; and H = high vulnerability. 
Page 171

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the English Language Unabridged (Springfield, MA: G.&C.

Merriam).

Typing text, tables, and figure captions: Text, tables, and

figure captions should be converted to WordPerfect. In general,

keep text simple (e.g., don't switch fonts and type sizes, don't use

hard returns within paragraphs, don't indent except to begin

paragraphs). Also, don't use an automatic footnoting function; all

notes should be indicated in the text by simple numerical superscripts, and listed together in an "Endnotes" section prior to the

"References Cited" section. Especially, don't use a graphics

function for embedding tables and figures in text.

Tables should be prepared with a table formatting function.

Each figure should be supplied both on paper and on disk, unless

there is no digital file of a given figure. Except under extraordinary

circumstances, color will not be used in illustrations.

Manuscript Preparation

Organization: Manuscripts must have an abstract, table

of contents, and -- if applicable -- lists of tables, figures, and

acronyms. As much as possible, use traditional scientific

manuscript organization for sections: "Introduction," "Study

Area," "Methods & Materials," "Results," "Discussion" and/

or "Conclusions," "Acknowledgments," and "References Cited."

Style: All NEFSC publication and report series are

obligated to conform to the style contained in the most recent

Northeast Fisheries Science Center

Operations, Management & Information Division

Research Communications Branch

Editorial Office

Manuscript Submission

Authors must submit one paper copy of the double-spaced

manuscript, one disk copy, and original figures (if applicable).

NEFSC authors must include a completely signed-off "NEFSC

Manuscript/Abstract/Webpage Review Form." Non-NEFSC authors who are not federal employees will be required to sign a

"Release of Copyright" form.

Send all materials and address all correspondence to: Jon A.

Gibson (Biological Sciences Editor), NMFS Northeast Fisheries

Science Center, 166 Water Street, Woods Hole, MA 02543-1026.
National Marine Fisheries Service

166 Water Street

Woods Hole, MA 02543-1026

Publications and Reports

of the

Northeast Fisheries Science Center

The mission of NOAA's National Marine Fisheries Service (NMFS) is "stewardship of living marine resources for the benefit of the

nation through their science-based conservation and management and promotion of the health of their environment." As the research

arm of the NMFS's Northeast Region, the Northeast Fisheries Science Center (NEFSC) supports the NMFS mission by "planning,

developing, and managing multidisciplinary programs of basic and applied research to: 1) better understand the living marine resources

(including marine mammals) of the Northwest Atlantic, and the environmental quality essential for their existence and continued

productivity; and 2) describe and provide to management, industry, and the public, options for the utilization and conservation of living

marine resources and maintenance of environmental quality which are consistent with national and regional goals and needs, and with

international commitments." Results of NEFSC research are largely reported in primary scientific media (e.g., anonymously-peerreviewed scientific journals). However, to assist itself in providing data, information, and advice to its constituents, the NEFSC

occasionally releases its results in its own media. Currently, there are three such media:

NOAA Technical Memorandum NMFS-NE -- This series is issued irregularly. The series typically includes: data reports of

long-term field or lab studies of important species or habitats; synthesis reports for important species or habitats; annual reports

of overall assessment or monitoring programs; manuals describing program-wide surveying or experimental techniques; literature

surveys of important species or habitat topics; proceedings and collected papers of scientific meetings; and indexed and/or

annotated bibliographies. All issues receive internal scientific review and most issues receive technical and copy editing.

Northeast Fisheries Science Center Reference Document -- This series is issued irregularly. The series typically includes: data

reports on field and lab studies; progress reports on experiments, monitoring, and assessments; background papers for, collected

abstracts of, and/or summary reports of scientific meetings; and simple bibliographies. Issues receive internal scientific review,

but no technical or copy editing.

Resource Survey Report (formerly Fishermen's Report) -- This information reportis a quick-turnaround report on the distribution

and relative abundance of selected living marine resources as derived from each of the NEFSC's periodic research vessel surveys

of the Northeast's continental shelf. There is no scientific review, nor any technical or copy editing, of this report.

OBTAINING A COPY: To obtain a copy of a NOAA Technical Memorandum NMFS-NE or a Northeast Fisheries Science Center

Reference Document, or to subscribe to the Resource Survey Report, either contact the NEFSC Editorial Office (166 Water St.,

Woods Hole, MA 02543-1026; 508-495-2228) or consult the NEFSC webpage on "Reports and Publications" (http://

www.nefsc.noaa.gov/nefsc/publications/).

ANY USE OF TRADE OR BRAND NAMES IN ANY NEFSC PUBLICATION OR REPORT DOES NOT IMPLY

ENDORSEMENT.

Media

 Mail