I. Introduction

An examination of SEFC data on the take of turtles incidental to non-shrimp trawling
fisheries was completed. Published reports and unpublished data were reviewed for
both the Atlantic from North Carolina to Florida and the Gulf of Mexico. Information
from the Gulf of Mexico includes data from the now defunct Japanese longline fishery,
the more recent domestic longline fishing, and the very limited butterfish fishery. In
the Atlantic information is primarily available from the pound net fishery of North
Carolina.

An examination of stranding data collected over the past 10 years was completed to
determine the feasibility of utilizing these data to define the relative extent of fisheries
related mortality throughout the region. The primary limitation of these data is
assigning cause of death. Whether entanglement occurred before or after a turtle died,
is not known and cannot be ascertained through histopathological examination of the
tissues. Thus, stranding data are circumstantial unless the entanglement was directly
observed and reported as such.

Il.Fishery Interactions

A.Gulf of Mexico
1.Surface Longline Fishing

The take of turtles incidental to longline fishing has been documented (Thompson, Jr.
1982; Reese 1983; Witzell 1984; M. Grace 1990 unpub. data NMFS Pascagoula
Laboratory). Witzell (1984) provides a review of data on turtle take incidental to the
Japanese bluefin tuna longline fishery in the North Atlantic from 1978 through 1981.
Observer reports and logbooks provided the data summarized by Witzell (1984). As
reported by Witzell (1984), of a total 57 turtles captured, 30 (53% of total) were caught
in the Gulf of Mexico. Of these 30, 12 (40%) were identified as leatherback turtles and
for the remaining 18 (60%), species was not included. Of these 30 total, 28 (93.3%)
were released alive. Eleven (92%) of the 12 leatherbacks were released alive. Twen-
ty-six turtles (87%) were caught within an area that represented 56.1% of the total
fishing effort in the Gulf of Mexico. Witzell (1984) estimated catch rates as defined as
turtles caught per 10,000 hooks (1805) and expanded this over the total effort in hooks
from 1978-1981 (11,329,069) to derive a value of 204 turtles captured over this four
year period. These could be apportioned as 82 leatherbacks (40%) and 122 unknown
(60%) based on observed proportions. More recently, observers have been placed on
domestic longline vessels from May 1985 to March 1986, and from October 1987 to the
present. The domestic effort is directed at yellowfin tuna, sharks, and swordfish. These
data were summarized by area which includes the Gulf of Mexico; the "South Atlantic"
defined as from North Carolina to South Florida; the "North Atlantic" from Virginia


Literature Cited

Bellamund, S.A.; J.A. Musick; RE. C. Klinger; R.A. Byles; J.A. Keinath; D.E. Barnard.
1987. Ecology of Sea Turtles. Final Contract Report No. NA80FAC-00004 to the
National Marine Fisheries Service, Northeast Region, Gloucester, MA. 18-22p.

Reese, G.B. 1983. Japanese longline fishing comparisons between 1980 observer and
Japanese report data and between 1979 and 1980 fishing activity and catch rates for the
Atlantic and Gulf of Mexico. NOAA Tech. Memo. NMFS-SEFC-125. 83p. + Ap-

pendices.

Thompson, P.A. Jr. Japanese longline fishing: Comparison between observer data and
Japanese quarterly reports for 1979 in the Atlantic and Gulf of Mexico. NOAA Tech.
Memo. NMFS-SEFC-64. 38pp. + Appendices.

Witzell, W.N. 1984. The incidental capture of sea turtles in the Atlantic U.S. Fishery
Conservation Zone by the Japanese tuna longline fleet, 1978-1981. Mar. Fish. Rev.
46(3): 56-S8p.


1989 in Pamlico Sound. Cold-stunning is not an unreasonable assumption since
December waters off North Carolina are relatively cold for this tropical/subtropical
species. Perhaps, the combined stress. from capture and sudden change in water
temperature may have acted synergistically to result in death.

Notably, the mesh sizes used by North Carolina pound net fishermen range from 2 inch
to 6 inch stretched mesh. Bellamund et al (1987) report on the catch and mortality of
turtles in the Chesapeake Bay pound net fishery. These nets were either of 6-12 inch
stretched mesh or 12-16 inch stretched mesh. In 1983 and 1984, Bellamund et al (1987)
reported that 57 turtles became entangled and died in pound nets.. The very low
mortality reported from North Carolina is likely attributed to the very small mesh sizes
used which probably entangle flippers rather than heads and thus, avoids prolonged
submergence. The best available information suggests that pound nets may be a
significant cause of turtle mortality in the Chesapeake Bay while turtles are not killed
in North Carolina pound nets.

3.Summer Flounder Bottom Trawling

The winter extension of the summer flounder fishery includes North Carolina waters.
During the week of Dec. 2, 1990 about 50 turtles stranded along North Carolina beaches
coincidental to the opening of this bottom trawling fishery in state waters to up to 15
vessels.

Examination of high-resolution sea surface temperatures from satellites that are
received routinely by the Southeast Fisheries Center through NOAA’s Coastwatch
Program indicated the presence of an intrusion of extremely warm Gulf Stream water
along the North Carolina coast from Cape Hatteras to Cape Lookout. It is
hypothesized that this warm water provided a haven for both fish and turtles, con-
centrating them along the beach.

On December 7, 1990, the State of North Carolina closed state waters for finfish
trawling from Cape Hatteras to Ocracoke Inlet. Turtle strandings ceased at this time.
Experimental trawling by the State of North Carolina using a commercial vessel
confirmed a large number of turtles in the area. Catch rates averaged one turtle for
every 3-4 hours of trawling.

Aerial surveys were conducted by North Carolina using trained observers from the
Southeast Fisheries Center and by scientists from VIMS. These surveys indicated that
large numbers of turtles were present from Cape Hatteras to Cape Lookout, extending
into the EEC.

Assistance was requested from the Southeast Fisheries Center by North Carolina to
modify an existing TED to allow exclusion of turtles and retention of flounder. A test
of a modified TED was made in the affected area. During 12 hours of trawling aboard
a commercial vessel, three turtles were caught in the standard net and none were caught
in the TED-equipped net. The flounder catch in the TED-equipped net was only about


to Maine; and U.S. Caribbean waters off Puerto Rico. Within the Gulf of Mexico, 4
turtles were captured and released alive from 8 trips totalling 70 observer days and 43
sets. Since October 1987, an observer program on domestic longline vessels is continu-
ing in the northern Gulf funded by MARFIN, to Louisiana State University (LSU).
During this period, 2 turtles were captured; both were identified as leatherback turtles;
both were released alive; and both were caught during swordfish longlining. These data
bases include positional and effort information such that CPUE estimates could be
developed and stratified by space and time and probably compared with these of Witzell
(1984). The fate of turtles released "alive" is unknown. Turtles will probably be
impacted if they swallow hooks and these remain in turtles or lines are cut leaving hooks
in turtles. Thus, even though turtles are released alive, mortalities may occur which
cannot be detected through our stranding network. ,

2.Bottom Trawling

The Pascagoula Laboratory directed an in-house observer program on butterfish
vessels from 1986 through 1989 (M. Grace 1990 unpub. data), Thirteen vessels par-
ticipated in the observer program and during 1,291 observed tows, 1 loggerhead turtle
was captured and released alive. The turtle was captured and released about 30 miles
south of Pascagoula, Mississippi in 26 fathoms of water. Over the four year observer
period, it was estimated that over 3,000,000 pounds of butterfish were landed. By 1990
it was determined that this.fishery included only one vessel operating out of Mississippi.
The extent of this fishery is so limited that at this time it is not a risk to turtles.

B.Atlantic

Fisheries operating within the southeast U.S., (North Carolina to Florida) were
evaluated from the North Atlantic. The Caribbean Sea has been included, and only
includes waters off Puerto Rico.

1.Surface Longline Fishing

During the Pascagoula Laboratory observer program for the domestic yellowfin fishery
referred to previously, 4 turtles were reported captured and released alive from the
Caribbean. These turtles were captured on 2 observer days and 34 sets. The same
potential for mortality exists with this fishery as with the Gulf of Mexico longline effort.

2.Pound Nets

Since 1988, the Beaufort Laboratory has tagged marine turtles in Pamlico and Core
Sounds, North Carolina through the cooperative efforts of pound net fishermen. Since
1988, a total of 134 turtles have been captured. Of these 134 turtles, have been
recaptured once, and one has been recaptured seven times. Of these 134 turtles, 93
(69%) were loggerhead; 15 (11%) were Kemp’s ridley; and 26 (19%) were green
turtles, 2 of which were reported as dead. These two dead green turtles were also
reported to the STSSN as cold-stunned and both turtles were captured in December


was first suggested via strandings and verified by the state with observers on vessels.
This fishery extends north from North Carolina and the extent of turtle captures and
mortality outside of NC waters is not known. Observer coverage is the best method
available to document turtle captures and mortalities incidental to fishing effort.


NOAA TECHNICAL MEMORANDUM

NMFS-SEFSC-285

Preliminary Information on Turtle Captures Incidental to Fishing

in Southeastern U.S. Waters

by

Nancy B. Thompson

May 1991

U.S. Department of Commerce
National Oceanic and Atmospheric Administration
National Marine Fisheries Service
Southeast Fisheries Science Center
75 Virginia Beach Dr.

Miami, FL 33149

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Table 1. A total of 378 turtles have been reported to the
STSSN from 1980-1989 as captured by or entangled in fishing
gear and reported as released alive. The number of turtles by

gear type and whether entangled or captured are listed.

Total

Method Number
Caught in Pound Net 90
Entangled in Fishing Gear 77
Capture by Hook and Line 63
Entangled in Crab/Lobster Trap Line 62
Entangled in Fishing Net 24
Caught in Gill Net 24
Caught in Fish Trap 18
Caught in Non Shrimp Bottom Trawl 10
Caught in Set Net 3
‘Caught in Seine Net 2
Caught in Cast Nest 2
Caught in Commercial Drift Net 1
Caught in Drift Net 1
Caught in Trot Line 1


6% less than in the standard net when a Southeast Fisheries Center accelerator funnel
was used, The states of North Carolina reopened the closed area to finfish trawling on
December 26, 1990. Each vessel was required to use the modified TED and to keep a
logbook to evaluate its effectiveness. Staff from the Southeast Fisheries Center are
providing assistance to local net makers on proper installation and use of the modified
TED.

Monitoring of the affected area continues. The Southeast Fisheries Center is providing
observers for aerial surveys and also is monitoring sea surface temperatures. North
Carolina plans to require the use of TEDs in this area until decreasing water tempera-
tures force the turtles offshore and/or south.

lll. Stranding Data

Data collected on turtles that wash up along the coastline are reported to the SEFC
Turtle Stranding and Salvage Network (STSSN). In addition, turtles captured alive and
dead incidental to fishing activities are reported opportunistically. Over the period
1980 through 1989, a total of 16,574 turtles have been reported to the STSSN. These
reports are provided to the STSSN via a state coordinator responsible for data verifica-
tion. Capture or entanglement by fishing gear has been reported for 378 (2%) turtles
captured by 13 different fishing gear types (Table 1). All turtles were reported as
captured and released alive.

IV. Miscellaneous Data

North Carolina fishermen have voluntarily reported to NMFS, captures incidental to
fisheries other than pound netting. These include long trawling (8 turtle), trawlers (5
turtles), gill nets (3 turtles) and longline (1 turtle). All were reported as captured and
released alive.

V. Conclusions

Anexamination of available observer data for commercial longline fishing indicate that
turtles, primarily leatherbacks, are captured and released alive. However, the fate of
these released turtles is not known and cannot be determined without observers on
vessels. Pound net fishermen in North Carolina also captured turtles and report
releasing them alive. Pound nets fishermen in Chesapeake Bay report significant
mortalities and use nets of larger mesh size than those used by North Carolina
fisherman. A recent occurrence of turtle strandings and observer data indicate that the
summer flounder fishery resulted in turtle mortalities off North Carolina. This take


Executive Summary

@ NMFS observer data are available on the capture, release of live turtles for
the domestic longline fishery. No mortalities have been reported, although
the subsequent condition and fate of turtles released alive is unknown.

e Fishermen in North Carolina voluntarily report incidental capture of turtles
in pound nets, longline, long hauling, and trawling.

 Stranding data recently provided circumstantial evidence on the capture and
mortality of turtles incidental to the North Carolina summer flounder fishery.
Capture was confirmed by state observers. TED’s, as modified and tested by
NMFS gear specialists from Pascagoula demonstrated that this gear is effec-
tive in significantly reducing turtle capture and mortality.

e Pound net fishermen off North Carolina report significant turtle captures and
live releases, as compared to relatively high mortalities by Chesapeake Bay
pound net entanglement. Mesh sizes used by North Carolina pound net
fishermen are smaller than those used by Chesapeake Bay fishermen, sug-
gesting that smaller mesh sizes prevent prolonged turtle submergence and
death. . .

The best approach available to verify and quantify turtle capture and mortality
is through the placement of observers on vessels.


Notice

The National Marine Fisheries Service (NMFS) does not approve, recommend, or
endorse any proprietary product or material mentioned in this publication. No
reference shall be made to NMFS, or to this publication furnished by NMEBS, in any
advertising or sales promotion which would indicate or imply that NMFS approved,
recommends, or endorses any proprietary product or proprietary material mentioned
herein or which has as its purpose any intent to cause directly or indirectly the
advertised product to be used or purchased because of NMFS publication.

This report should be cited as follows:
Thompson, N.B. 1991. Preliminary Information on Turtle Captures Incidental to

Fishing in Southeastern U.S. Waters. NOAA Technical Memorandum NMEFS-
SEFSC-285, 8 p.

Copies may be obtained in writing from:
Dr. N.B. Thompson

NMFS/SEFSC

75 Virginia Beach Dr.

Miami, FL. 33149

or

NTIS

5288 Port Royal Rd.

Springfield, VA. 22161


NOAA Technical Memorandum

NMFS-SEFSC-285

Preliminary Information on Turtle Captures Incidental to Fishing in Southeastern
U.S. Waters

by

Nancy B. Thompson

The Technical Memorandum series is used for documentation and timely com-
munication of preliminary results, interim reports, or special-purpose inforamtion.
Although the memoranda are not subject to complete formal review, editorial con-
trol, or detailed editing, they are expected to reflect sound professional work.

U.S. Department of Commerce
Robert A. Mosbacher, Secretary
National Oceanic and Atmospheric Administration
John A. Knauss, Under Secretary for Oceans and Atmosphere
National Marine Fisheries Service

William W. Fox, Jr., Assistant Administrator for Fisheries