Page 16

Figure 20. Distribution (as number
per tow) of sexually
immature windowpane
(<24 cm) based on spring
NEFC bottom trawl survey
ctuises, 1968-86

Figure 21. Distribution (as number
per tow) of sexually
immature windowpane
(<24.cm) based on autumn
NEFC bottom trawl survey
cruises, 1968-86

4s

39

4s

39

73 72 n 70

NEFC BOTTOM TRARL SURVET
SPRING 1968 - 1986

DENSITY OISTAIBUTION OF IMMATURE HINOOHPANE 4e
NUMBER PER TOW
8 18
9 2s
{o} 26
39
73 72 a 10

NEFC BOTTOM TAAKL SURVEY
FALL 1968 - 1986

DENSITY DISTRIBUTION OF IMMATURE WINDOWPANE 40
NUMBER FER TOW
3 6-10
8 Me 25
> 26
39
73 6s


Page 10

Figure 8. Distribution (as number
per tow) of sexually
immature yellowtail
flounder (<20 cm) based
on spring NEFC bottom
trawl survey cruises, 1968-
86

Figure 9. Distribution (as number
. per tow) of sexually
immature yellowtail
flounder (<20 cm) based
on autumn NEFC bottom
trawl survey cruises, 1968-

86

73 72 a 79 69 68 87. 86 65
4s us
NEFC BOTTOM TRAWL SURVEY
RING 1958 - 1986
44
43
ye
on
q
g
re DENSITY DISTRIBUTION OF IMMATURE YELLOWTAIL FLOUNDER] YO
NUMBER PER TOW
7 ° l=
° s- 10
8 = 8s
> 36
30% 38
73 v2 a 70 69 68
4S
NEFC BOTTOM TRAWL SURVEY
FALL 1968 - 1986
ne &
a
. .
aN
oa . .
- 8
oot "
° © 2

39

DENSITY DISTRIBUTION OF IMMATURE YELLOWTRIL FLOUNDER
NUMBER PER TOW

1-8

6 10

n 25
36

Qoee

73

39
65


Page 1

ABSTRACT

NS canes of data obtained from research vessel survey cruises over a 19-year period reveal distinctive patterns
in the geographic occurrence of immature fish. These occurrences provide qualitative evidence for potentially sig-
nificant fishing mortality of the sexually immature components of 10 species in the Gulf of Maine-Georges Bank-
Southern New England region, where substantial overlap exists between unregulated mesh/exempted fishing areas

and the distributions of these immature fish <2————

INTRODUCTION

Ifone goal of fishery management is to prevent recruit-
ment overfishing, then it becomes important to define
season and area combinations where juvenile mortality is
likely to occur. While numerous distribution studies of
Northwest Atlantic groundfish exist (Bigelow and Schroe-
der 1953; Leim and Scott 1966; Bowman 1981; Grosslein
and Azarovitz 1982; Scott 1988), most do not specifically
consider juvenile distribution patterns. A study by Bow-
man et al. (1987) on food habits and distribution of juve-
niles for 17 species was based upon fish of age 1 or less, but
did not cover the full period to sexually maturity. Bowman
(1981) examined the distribution and abundance of juve-
niles for 15 species, but not to the geographic and seasonal
resolution necessary for evaluation from management
perspectives. .

This study describes distribution of juveniles of the 10
groundfish species in the Gulf of Maine-Georges Bank-
Southern New England region (Figure 1) subject to regula-
tion under the New England Fishery Management Coun-
cil’s Northeast Multispecies Fishery Management Plan
(FMP), and evaluates the distribution patterns with respect
to regulatory areas established by the FMP. Regulated
species include haddock (Melanogrammus aeglefinus),
Atlantic cod (Gadus morhua), yellowtail flounder (Li-
manda ferruginea), American plaice (Hippoglossoides plates-
soides), witch flounder (Glyptocephalus cynoglossus), redfish
(Sebastes fasciatus), pollock (Pollachius virens), white
hake (Urophycis tenuis), windowpane (Scophthalmus
aquosus), and winter flounder (Pseudopleuronectes ameri-
canus). Under the FMP, otter-trawl stretch mesh size is
regulated at 5.5 inches (140 mm) for most of Georges Bank
and the Gulf of Maine (Figure 2); exempted small-mesh
fisheries are allowed in the area extending from Cape Cod
north along the inshore segment of the Gulf of Maine.
Mesh size is generally not regulated in areas west and south
of Cape Cod including the southern flank of Georges Bank;
however, the Nantucket Shoals region is included in the
large-mesh area and is regulated December through March
(Figure 2). In addition, a spawning area closure to protect
yellowtail flounder is in effect from March/April to May.!
Results presented herein may be used to assess qualita-
tively the impacts of management measures (e.g., effects of
small-mesh areas) on the mortality of juvenile fish.

- the southern edge of Georges Bank.

METHODS

Data have been obtained from annual Northeast Fish-
eries Center (NEFC) spring and autumn bottom trawl
surveys (Grosslein 1969; Azarovitz 1981) conducted since
1968 during March to May and September to November,
respectively. NEFC survey coverage within the study area
is shown in Figure 3; sampling intensity within strata is
summarized in Table 1. Maturity ogives were inspected to
determine the smallest length at which individuals of each
species were observed to be sexually mature (Table 2);
immature fish were defined as those falling below that
length: Catches (as number per tow) of immature fish were
plotted by survey haul location. Data from 1968-86 sur-
veys have been aggregated and plotted for each species by
season (spring and autumn). Year-around regulated mesh
areas delineated by the FMP (Figure 2) are superimposed
for reference purposes; the seasonal areas (Nantucket Shoals
and Southern New England spawning closure) are superim-
posed on spring plots only. Mean values of depth were
calculated for juveniles of each species (Table 3).

RESULTS

Haddock

Immature haddock are most concentrated at depths
near or Jess than 100 m during both spring and autumn
(Table 3, Figures 4 and 5S). In spring, concentrations appear
from just south of Jeffreys Ledge to Cape Cod, and along
In autumn, these
aggregations remain and are augmented by concentrations
on Georges Bank extending from the Northeast Peak and
along the Northern Edge to the Great South Channel
region. The potential for juvenile mortality exists in the
southern Gulf of Maine exempted area and the southern
portion of Georges Bank during both seasons.

Atlantic Cod

Immature Atlantic cod are generally found at depths
less than 100 m (Table 3, Figures 6 and 7). In the spring,
concentrations occur between Jeffreys Ledge and Cape

+ Specific coordinates are described in Federal Register, 50 CFR Part 651, September 17, 1987.


45

45

Page 17

23 2 a 20 69

Figure 22. Distribution (as number
per tow) of sexually
immature winter flounder
(<20 cm) based on spring
NEFC bottom trawl
survey cruises, 1968-86

NEFC BOTTOM TARKL SUAVEY
SPRING 1968 - 1986

DENSITY DISTRIBUTION OF IMMATURE WINTER FLOUNDER, 40

a9

NURBER PER TOH
° 1
8 6- 10
8 We 88
> 26
39
2 7, . peste:
73 i2 it ° ss ee ae Ss 2°45 Figure 23. Distribution (as number
per tow) of sexually
NEFC BOTTOM TARHL SURVEY immature winter flounder
FALL 1868 - 1986
(<20.cm)based on autumn
NEFC bottom trawl
44 survey cruises, 1968-86

43

42

at

QENSITY DISTRIBUTION OF IMMATURE HINTER FLOUNDER 40

39

NUMBER FER TOK
° 6- 10
‘ Q a 25
6 > 8
39
3 6S

FX Us S. GOVERNMENT PRINTING OFFICE: 1991-=500-031--40000


Page 14

Figure 16. Distribution (as number 45
per tow) of sexually
immature pollock (<30 Mere
cm) based on spring NEFC
bottom trawl survey
cruises, 1968-86

BOTTOM TRAHKL SURVEY
G 1968 - 1966

DENSITY DISTRIBUTION OF IMMATURE POLLOCK

uo
NUMBER PER TOW
: 1
° 6 10
Q es 8
o > 26
3g 39
. - teibaati z
Figure 17. Distribution (as number ys 72. 2 u 70
per tow) of sexually
i NEFC BOTTOM TAAWL SURVEY
immature pollock (<30 NEFC BoTrOM TAaW
cm) based on autumn
NEFC bottom trawl survey
ctuises, 1968-86

OENSITY DISTRIBUTION OF IMMATURE POLLOCK 40

NUMBER PER TOW
. 1-8
° 6- 10
Q = 25
iu) > 36

39
39 > 6s


Page 6

Table 2. Length at which fish are first observed to be mature (i.e., fraction mature below this length = 0)

Species Length Source
(cm)

Haddock 31 Morse 1979
Atlantic cod 37 Morse 1979
Yellowtail flounder 20 Morse 1979
American plaice 20 Morse 1979
Witch flounder 25 Morse 1979
Redfish 22" Perlmutter & Clarke 1949
Pollock 30° Beacham 1983
White hake 34 Morse 1979
Windowpane 24 Bigelow and Schroeder 1953
Winter flounder 20 Morse 1979

“Estimated values.

Table 3. Mean depth, standard deviation, and range of depth for juveniles of 10 species from NEFC spring and autumn bottom trawl
surveys, 1968-86 ;

Spring Autumn

Species No. Mean Stand. Range No. Mean Stand. Range
Depth Dev. Min. Max. : Depth Dev, Min. Max.
(m) (mm) (m) (m)— (m)
Haddock 20688 95.3 22.0 25.0 279.0 24018 87.8 274 23.0 516.0
Atlantic cod 4182 61.7 32.4 10.0 353.0 4969 74.9 29.0 11.0 331.0
Yellowtail flounder 3014 47.3 22.2 9.0 179.0 3115 63.0 26.9 14.0 287.0
American plaice 8124 95.2 37.6 20.0 307.0 6595 105.0 40.2 25.0 351.0
Witch flounder 1275 160.9 96.5 23.0 494.0 484 133.3 70.8 38.0 516.0
Redfish 8602 161.5 60.2 37.0 389.0 17189 147.6 50.3 34.0 382.0
Pollock 1727 88.2 44.5 13.0 232.0 419 78.5 416 26.0 240.0
White hake 2311 = 139.8 56.4. 11.0. 470.0 4735, 775 49.2 11.0 369.0
Windowpane 10931 26.6 23.2 5.0 166.0 9374 38.3 182 ° 70 175.0

Winter flounder 4099 25.6 12.5 5.0 204.0 856 39.8 13.7 70 94.0



Figure 2. Regulated mesh (5.5 inches)

68 58 57

and exempted fishery areas “s

under the New England
Fishery Management
Council’s Northeast
Multispecies Fishery
Management Plan

REGULATED MESH AREAS

4y

43

100 HETERS

Exempted fishing permissible 40
No exempted fishing (regulated mesh)
No exempted fishing (Dec.-Mar.)

spawning closure (Mar./Apr.-May)

39

39

New England, immature fish are found mid-shelf at depths
around 45 m in spring and 60 m in autumn (Table 3). Spring
distribution is generally northward of the spawning area
closure. Significant juvenile mortality may occur in the
Southern New England region where mesh size is unregu-
lated.

American Plaice

Immature American plaice are strongly concentrated
along and inside the 100-m isobath in the western Gulf of
Maine during spring and autumn (Table 3, Figures 10 and
11). They are found scattered in the deeper waters of the
western and central Gulf of Maine, and on the northern
edge of Georges Bank. For the most part, immature
American plaice are unprotected by the regulated mesh
area. Significant discarding of juvenile plaice has been
observed in association with the small-mesh shrimp fishery
in the western Gulf of Maine during December through
May (Stephen H. Clark, NEFC, personal communication).

Witch Flounder

Immature witch flounder in the New England region
concentrate between Cape Cod and Cape Ann, inshore of

Jeffreys Ledge, and intermittently across the northern Gulf
of Maine (Table 3, Figures 12 and 13). Distribution does
Not appear to shift widely between spring and autumn. As
with American plaice, witch flounder juvenile aggrega-
tions do not occur within the regulated area, and are subject
to mortality incurred from the shrimp fishery.

Redfish

Immature redfish are distributed over the entire Gulf of
Maine (Table 3, Figures 14 and 15), but appear most
concentrated from Stellwagen Bank north along the west-
ern side of the Gulf of Maine during spring. In autumn, this
distribution extends northward into the central Gulf of
Maine. Some juvenile mortality may occur in the ex-
empted small-mesh fisheries prosecuted in the western
Gulf of Maine.

Pollock

Immature pollock are distributed in the northern Gulf
of Maine, and between Cape Cod and Jeffreys Ledge at
depths less than 90 m (Table 3, Figures 16 and 17) in both
spring and autumn. Juveniles also appear along the North-
east Peak of Georges Bank in the spring.


Page 2

73 72 71 70 63 68 67 66 6S
4S us
uy
GULF OF MAINE
Jeffreys Ledge Us-Canadian Boundary 43
Cape Ann
Massachusetts Bay
Stel Lmagen Bank uorther \Edae
ue
Cape Cod Bay Northeast) Peak
Cape’ Cod
: ‘1 y)
Wo ee Was a Great South Chanel
~~ Narragansett Gay \
fos > ° wantucket shoals GEORGES BANK
41
SOUTHERN NEW ENGLAND
4O
100 METERS
“8 39

Figure 1. Gulf of Maine, Georges Bank, and Southem New England regions of the Northwest Atlantic Ocean, showing geographic

features referred to in this study

Cod and in the Nantucket Shoals region, and are widely
distributed over Georges Bank. Distributions in autumn
are mote restricted, occurring primarily inshore of the 100-
m isobath and principally in three areas: Massachusetts
Bay, southeast of Cape Cod, and the Northeast Peak of
Georges Bank. Seasonal mesh Tegulations on Nantucket
Shoals (Figure 2) have been established specifically to
Protect juvenile cod from December to March; however,
juvenile mortality may occur in the southern Gulf of Maine
exempted area during both seasons. A detailed account of
juvenile cod distribution is given by Wigley and Serchuk
(submitted).

Yellowtail Flounder

Immature yellowtail flounder are usually found well
inshore of 100 m (Table 3). In the Gulf of Maine, they are
concentrated between Massachusetts Bay and Cape Cod
Bay, and along outer Cape Cod in both spring and autumn
(Figures 8 and 9), Immature individuals are found during
spring along the southern edge of Georges Bank where their
distribution is within the regulated mesh area. In autumn,
concentrations shift to the north, near the Great South
Channel, but primarily eastward to slightly deeper waters
along the southeastern part of Georges Bank. In Southern


us

39

4s

39

63 68

4

NEFC BOTTOM TRAWL SUAVET
SPRING 1968 - 1986

Geos

MUNBER FER TON

10
25
26

DENSITY®OISTAIBUTION OF IMMATURE WHITE HAKE

39

73 72 a

70

69

S

NEFC BOTTOM TRAWL SURVEY
FALL 1968 - 1886

8

NUMBEA PER TOW
1-8

6- 10
We 25
> 26

© DENSITY ‘DISTRIBUTION OF IMMATURE WHITE HAKE

4u

43

42

4

40

39

Ta

6s

Page 15

Figure 18. Distribution (as number
per tow) of sexually
immature white hake (<34
cm) based on spring NEFC
bottom trawl survey
cruises, 1968-86

Figure 19. Distribution (as number
per tow) of sexually
immature white hake (<34
cm) based on autumn
NEFC bottom trawl
survey cruises, 1968-86


Page 5

Table 1. Standard aumber of tows per stratum, surface area of each stratum (square miles), and resulting ratio (square miles per tow)
for NEFC inshore and offshore bottom trawl survey strata used in this analysis

Inshore Strata Offshore Strata
Stratum Tows Area Ratio Stratum Tows Area - Ratio
1 1 70 70.0 1 7 3470 495.7
2 2 15 37.5 2 7 2925 4179
3 1 65 65.0 3 3 795 265.0
4 2 55 275 4 3 305 101.7
5 2 10 70.0 5 5 2005 401.0
6 1 10 70.0 6 8 3720 465.0
7 2 105 52.5 7 3 695 321.7
8 2 195 97.5 8 3 330 110.0
9 1 70 70.0 9 5 2115 423.0
10 2 65 32.5 10 8 3750 468.8
su 2 280 140.0 u 3 840 280.0
45 2 255 127.5 12 3 300 100.0
46 2 325 162.5 13 9 3280 364.4
47 2 130 65.0 14 4 930 232.5
49 2 460 230.0 15 3 400 133.3
1 2 185 92.5 16 10 4015 401.5
52 5 830 166.0 17 4 495 123.8
54 3 375 125.0 18 3 300 100.0
55 5 675 135.0 19 9 3345 371.7
56 1 65 65.0 20 6 1675 279.2
58 1 155 155.0 21 4 675 168.8
59 1 140 140.0 22 4 675 168.8
60 2 200 100.0 23 5 1400 280.0
61 2 255 127.5 24 6 3435 572.5
63 1 115 115.0 25 4 540 135.0
64 1 150 150.0 26 ~  S 1390 278.0
65 1 125 125.0 27 4 1040 260.0
66 2 215 107.5, 28 7 3145 449.3
68 1 70 70.0 29 8 4715 589.4
69 1 85 85.0 30 3 890 296.7
n 1 135 135.0 31 7 2645 3779
2 2 195 97.5 32 5 930 186.0
14 1 110 110.0 33 4 1145, 286.3
75 1 145 145.0 34 6 2420 403.3
1 1 50 50.0 35 4 1510 377.5
78 1 60 60.0 36 8 5570 696.3
80 1 95 95.0 37 5 2780 556.0
81 1 70 70.0 38 5 3470 694.0
83 1 120 120.0 39 5 1070 214.0
~ 85 1 145 145.0 40 3 665 221.7
87 2 240 120.0
89 1 95 95.0
90 2 350 175.0

The Gulf of Maine exempted fishery area, where
small-mesh fisheries (i.e., northern shrimp and silver hake)
have been prosecuted traditionally, encompasses seasonal
concentrations of juveniles for eight Gulf of Maine stocks:
haddock, Atlantic cod, yellowtail flounder, American plaice,
witch flounder, redfish, pollock, and white hake.

The unregulated mesh area extending along the south-
em edge of Georges Bank includes areas with relatively
high concentrations of immature haddock and windowpane
during the spring. Southern New England stocks of Atlan-

tic cod, yellowtail flounder, windowpane, and winter floun-
der are potentially vulnerable to juvenile fishing mortality
over their range due to the absence of mesh restrictions in
the area.

This study suggests that it may be possible to reduce
juvenile mortality considerably by different configurations *
of aréa/seasonal closures than those currently employed.
As more catch and discard data become available from the
NEFC Domestic Sea Sampling Program (initiated in 1989),
greater spatial and temporal resolution will be possible.


y —
2101617

: int
«AAT |
Ss. NOAA Technical Memorandum NMFS-F/NEC-80

~

3 This TM series is used for documentation and timely communication of preliminary results,
n fi interim reports, or special purpose information, and has not undergone external scientific
>> i review.
Prmment oF S

Distribution of Sexually Immature
Components of 10 Northwest Atlantic
Groundfish Species Based on Northeast
Fisheries Center Bottom Trawl Surveys,
1968-86

Susan E. Wigley and Wendy L. Gabriel
Woods Hole Lab., National Marine Fisheries Serv., Woods Hole, MA 02543

U. S. DEPARTMENT OF COMMERCE
Robert A. Mosbacher, Secretary
National Oceanic and Atmospheric Administration
John A. Knauss, Administrator
National Marine Fisheries Service
William W. Fox, Jr., Assistant Administrator for Fisheries

Northeast Fisheries Center

Woods Hole, Massachusetts

January 1991



Page 8

Figure 4.

Figure 5.

Distribution (as number
per tow) of sexually
immature haddock (<31
cm) based on spring NEFC
bottom trawl survey
ctuises, 1968-86

Distribution (as number
per tow) of sexually
immature haddock (<31
cm) based on autumn
NEFC bottom trawl! survey
ctuises, 1968-86

73 72

a 70

48

39

4s

1968 -

NEFC BOTTOM TARI
ATNG

ML SUAVE
986

DENSITY OISTRIBUTION OF IMMATURE HAQOCCK
NUMBER PER TOW

° r- S$

© 6 10

soy T- 2s

o > 26
73 72 cn 70

40

39

FALL 1968 -

39

NEFC BOTTOM TRAWL SURVEY
1986

DENSITY

Gooe

DISTRIBUTION OF IMMATURE HADDOCK
NUMBER PER TOH

40

3g

73

6s


Page 7

REFERENCES CITED

Azarovitz, T.R. 1981. A brief historical review of the
Woods Hole Laboratory trawl survey time series. Can.
‘Spec. Publ. Fish. Aquat. Sci. 58: 62-67.

Beacham, T.D. 1983. Variability in size or age at sexual
maturity of white hake, pollock, longfin hake and silver
hake in the Canadian Maritime area of the Northwest
Atlantic Ocean. Can. Tech. Rep. Fish. Aquat. Sci. No.
1157. 43 pp.

Bigelow, H.B., and W.C. Schroeder. 1953. Fishes of the
Gulf of Maine. Fish: Bull. U.S. 53. 577 pp.

Bowman, R.E. 1981. Distribution and abundance: of the
juveniles of fifteen selected fish species caught in the
Northwest Atlantic, 1975-1979. [Nat. Mar. Fish. Serv.,
Northeast Fish. Ctr.,] Woods Hole Lab. Ref. Doc. No. 81-
02. 53 pp.

Bowman, R.E., T.R. Azarovitz, E.S. Howard, and B.P.
Hayden. 1987. Food and distribution of juveniles of
seventeen Northwest Atlantic fish species, 1973-1976.
NOAA [Nat. Ocean. Atmos. Admin.] Tech. Mem. NMFS
[Nat. Mar. Fish. Serv.]-F/NEC-45. 57 pp.

Grosslein, M.D. 1969. Groundfish survey program of BCF
Woods Hole. Comm. Fish. Rev. 31(8-9): 22-35.

Grosslein, M.D., and T.R. Azarovitz. 1982. Fish distribution.
[Nat. Ocean. Atmos. Admin.,] MESA [Mar. Ecosyst.
Anal. Prog.] N.Y. Bight Atlas Monogr. 15. 182 pp.

Leim, A.H., and W.B. Scott. 1966. Fishes of the Atlantic
coast of Canada. Bull. Fish. Res. Bd. Can. 155. 485 pp.

Morse, W.W. 1979. An analysis of maturity observations
of 12 groundfish species collected from Cape Hatteras,
North Carolina to Nova Scotia in 1977. [Nat. Mar. Fish.
Serv., Northeast Fish. Ctr.,] Sandy Hook Lab. Rep. No.
79-32. 20 pp. ~

Perlmutter, A.,and G.M. Clarke. 1949. Age and growth of
immature rosefish (Sebastes marinus) in the Gulf of
Maine and off Nova Scotia. Fish. Bull, U.S. 51: 207-
228.

Scott, J.S. 1988. Seasonal spatial distributions of ground-
fishes of the Scotian Shelf. Can. J. Fish, Aquat. Sci. 39:
943-947.

Wigley, S.E., and F.M. Serchuk. (Submitted.) Spatial and
temporal distribution of juvenile Atlantic cod in the
Georges Bank - Southern New England region. Fish.
Bull, U.S.


Page 4

Figure 3. Northeast Fisheries Center bottom trawl survey strata used in this study: inshore = 1-14 and 45-90, and offshore = 1-40

White Hake

Immature white hake are common in the spring along
the 100-m contour and in deeper waters from Cape Cod
northward into the Gulf of Maine; however, some catches
have been observed inshore of 100 m in Cape Cod Bay and
Massachusetts Bay. During autumn, they are‘also concen-
trated along the 100-m contour. Immature white hake are
more abundant in the central Gulf of Maine in the spring
than autumn. The pattern is reversed for Georges Bank:
juveniles are absent in spring, but relatively common in
autumn over Georges Bank (Table 3, Figures 18 and 19).
Significant juvenile mortality may occur in the western and
northern Gulf of Maine, particularly in the autumn, in the
exempted fishery area. -

Windowpane

Immature windowpane are concentrated in Southern
New England during both seasons at depths around 30 m
(Table 3, Figures 20 and 21). In spring, concentrations
extend along the southern boundary of the regulated mesh
area of Georges Bank. However, in autumn, immature fish
are concentrated in the central area of Georges Bank within
the regulated area. The potential for high juvenile mortal-
ity exists in the Southern New England region except
during the spring when juvenile windowpane aggregations
coincide with the spawning area closure.

Winter Flounder

Sampling of immature winter flounder from inshore
stocks by the NEFC surveys may not be representative:
immature individuals are distributed close to estuaries and
in shallower waters inside the limits of the survey. Concen-
trations are observed at 25 m during spring in Cape Cod
Bay, and south and west of Narragansett Bay (Table 3,
Figure 22), and may be subjected to significant mortality in
these areas. In autumn, juvenile fish are dispersed through-
out the region (Figure 23). Extremely few individuals have
been observed along the outer edge of the shelf. Immature
winter flounder occurring on Georges Bank are within the
regulated mesh area.

DISCUSSION

The summary distributions of immature fish presented
above are based on extensive data sets obtained over a
period of 19 years. They reveal distinct patterns of geo-
gtaphic occurrence which are useful for management pur-
poses. There are substantial overlaps between exempted
fishing/unregulated mesh areas created by the New Eng-
land Fishery Management Council’s Northeast Multispe-
cies FMP and distributions of the sexually immature com-
ponents of many stocks.





Page iv

Figure 20. Distribution of sexually immature windowpane based on spring NEFC bottom trawl
survey cruises, 1968-86....
Figure 21. Distribution of sexually immature windowpane based on autumn NEFC bottom trawl
survey cruises, 1968-86 ..
Figure 22. Distribution of sexually immature winter flounder based on spring NEFC bottom trawl
survey cruises, 1968-86 ..
Figure 23. Distribution of sexually immature winter flounder based on autumn NEFC bottom trawl
survey cruises, 1968-86 ....



4s

3g

4s

39

5
4S

73 22 a 70 63 6a 67... 66 6
NEFC BOTTOM TAAWL SUAVET
SPRING 1986 - 1986

uy
43
ua
DENSITY, DISTRIBUTIGN OF IMMATURE AMEAICAN PLAICE 4O
NUNBER PER TO
° 1 -

3 6- 10

8 ns 88

> 38
39

69 5

NEFC BOTTOM TI
FALL 1968 - 1

AKL SURVEY
986

wu

43

42

41

DENSITY DISTRIBUTION OF IMMATURE AMERICAN PLAICE 40
MUMBER PER TOW
. te S
° 5 10
8 i= 85
> 26
39
13 6s

Page 11

Figure 10. Distribution (as number
per tow) of sexually
immature American
plaice (<20 cm) based on
spring NEFC bottom trawl
survey cruises, 1968-86

Figure 11. Distribution (as number
per tow) of sexually
immature American
plaice (<20 em) based on
autumn NEFC bottom
trawl survey cruises, 1968-
86


Page 13

73 2 a i § Figure 14, Distribution (as number
per tow) of sexually
NEFC BOTTOM TRAWL SURVEY immature redfish (<22
SPRING 1968 - 1986 .
cm) based on spring NEFC
bottom trawl survey
cruises, 1968-86
Oee
© © DENSITY DISPRIBUTION OF IMMATURE REOFISH 40
NUMBER PER TOW
° 1-8
° B- 10
9 ws 25
fo} > 8
39
73 72 7 ~ 70-88 &8 = ‘us Figure 15. Distribution (as number

per tow) of sexually
immature redfish (<22
cm) based on autumn
NEFC bottom trawl
44 survey cruises, 1968-86

NEFC BOTTOM TRAKL SURVEY
FALL 1968 - 1986

42

4

DENSITY DISTRIBUTION OF IMMATURE AEOFISH

40
NUABER PER TOW
. 1-8
2 6- 10
8 Me 28
> 26
39

73 6s


Page iii

TABLE OF CONTENTS

Abstract ...
Introduction
Methods
Results
Discussion ..
References Cited

MaH HEB

LIST OF TABLES

Table 1. Standard number of tows per stratum, surface area of each stratum, and resulting ratio
for NEFC inshore and offshore bottom trawl survey strata used in this analysis .....

Table 2. Length at which fish are first observed to be mature......

Table 3. Mean depth, standard deviation, and range of depth for juveniles of 10 species from
NEFC spring and autumn bottom trawl surveys, 1968-86"

LIST OF FIGURES

Figure 1. Gulf of Maine, Georges Bank, and Southern New England regions of the
Northwest Atlantic Ocean, showing geographic features referred to in this study ....
Figure 2. Regulated mesh and exempted fishery areas under the New England Fishery
Management Council’s Northeast Multispecies Fishery Management Plan
Figure 3. Northeast Fisheries Center bottom trawl survey strata used in this study:
inshore = 1-14 and 45-90, and offshore = 1-40...
Figure 4. Distribution of sexually immature haddock based on spring NEFC bottom trawl
Survey cruises, 1968-86 ....
Figure 5. Distribution of sexually immature haddock based on autumn NEFC bottom trawl
survey cruises, 1968-86 ...
Figure 6. Distribution of sexually immature Atlantic cod based on spring NEFC bottom trawl
survey cruises, 1968-86 ...
Figure 7. Distribution of sexually immature Atlantic cod based on autumn NEFC bottom trawl
Survey cruises, 1968-86 ...
Figure 8. Distribution of sexually immature yellowtail flounder based on spring NEFC bottom
trawl survey cruises, 1968-86
Figure 9. Distribution of sexually immature yellowtail flounder based on autumn

trawl survey cruises, 1968-86 10
Figure 10. Distribution of sexually immature American plaice based on spring NEFC bottom

trawl survey cruises, 1968-86 1d
Figure 11. Distribution of sexually immature American plaice based on autumn NEFC bottom

trawl survey cruises, 1968-86...... wee 11
Figure 12. Distribution of sexually immature witch flounder based on spring NEFC bottom

trawl survey cruises, 1968-86....... 12

Figure 13. Distribution of sexually immature witch flounder based on autumn NEFC bottom
trawl survey cruises, 1968-86......
Figure 14. Distribution of sexually immature redfish based on spring NEFC bottom trawl
survey cruises, 1968-86 ....
Figure 15. Distribution of sexually immature redfish based on autumn NEFC bottom trawl
survey cruises, 1968-86 ...
Figure 16. Distribution of sexually immature pollock based on spring NEFC bottom trawl
survey cruises, 1968-86
Figure 17. Distribution of sexually immature pollock based on autumn NEFC bottom trawl
survey cruises, 1968-86 ...
Figure 18. Distribution of sexually immature white hake based on spring NEFC bottom trawl
survey cruises, 1968-86 ..
Figure 19. Distribution of sexually immature white hake based on autumn NEFC bottom trawl
survey cruises, 1968-! 86

15

Preceding Page Blank |

—/





4s

38

“5

39

69

NEFC CTION TARHL SURVEY
SPAING 1968 - 1986

DENSITY DISTRIBUTION OF IMMATURE ATLANTIC COD yo
NUMBER PER TOW

. b- 8

© 6- 10

Q 25

fo) > 2
33

73 7 a 70 69

U5

FALL 1968 = 1

NEFC BOTTOM TRAHL SURVEY
986

8

DENSITY DISTRIBUTION OF IMMATURE COD

NUMBER PER TOW
1-5

6- 10
Me 28
> 2

44

43

42

4

40

39

Ta

65

Page 9

Figure 6. Distribution (as number
per tow) of sexually
immature Atlantic cod
(<37 cm) based on spring
NEFC bottom trawl
survey cruises, 1968-86

Figure 7. Distribution (as number
per tow) of sexually
immature Atlantic cod
(<37cm)based on autumn
NEFC bottom trawl
survey cruises, 1968-86


Page 12

Figure 12. Distribution (as number
per tow) of sexually
immature witch flounder
(<25 cm) based on spring
NEFC bottom trawl survey
cruises, 1968-86

Figure 13. Distribution (as number
per tow) of sexually
immature witch flounder
(<25 cm) based on autumn
NEFC bottom trawl survey
cruises, 1968-86

4S

39

u

70

SPRING 1968 -

NEFC BOTTOM TRAWL SUAVEY
1966

ee 5 QENSILY UISTRISUTION OF IMMATURE WITCH FLOUNDER 40

NUMBER PER TOW
r- 8

8 6-10
8 3s
> 8B
39
23 a n 10 a

NEFC BOTTOM TR
FALL 1968 - 19

AKL SUAVET
86

8

+ DENSI[Y DISTRIBUTION OF IMMATURE HITCH FLOUNDER 40

NUMBER PER TOW
1-5

10
= 88

26

Ta

39
6s