NOAA Technical Memorandum NMFS NE 111
Review and Evaluation
of the 1994 Experimental
Fishery
in Closed Area II
on
Georges Bank
by Patricia Gerrior1,
Fredric M. Serchuk1, Kathleen C. Mays1,John F. Kenney2,
and Peter D. Colosi2
1National Marine
Fisheries Service, Woods Hole, MA 02543
2National Marine Fisheries
Service, Gloucester, MA 01930
Print
publication date October 1996;
web version posted April 2001
Citation: Gerrior P, Serchuk FM, Mays KC, Kenney JF, Colosi PD. 1996. Review and Evaluation of the 1994 Experimental
Fishery in Closed Area II
on
Georges Bank. US Dep Commer, NOAA Tech Memo NMFS NE 111; 52 p.
Download complete PDF/print version
Summary
During January-June 1994, an experimental fishery was conducted on Georges
Bank in the expanded portion of Area II, an area closed to fishing during
that period. (“Area II” refers to just the expanded portion of
Area II unless noted otherwise.) Purpose of the experimental fishery
was to monitor the catch and bycatch of Atlantic cod and haddock in Area
II during its closure. During the fishery, 12 vessels from five
New England ports made 14 trips, totaling 522 tows and 1881.9 hr fished
(gear on bottom). All trips were conducted with Northeast Fisheries
Science Center scientific observers on board. Observers recorded
data on catches, discards, fishing effort, and gear characteristics,
and collected size-frequency samples of haddock and other species.
Vessels
were not restricted to fishing solely in the experimental area; all trips
but one fished both inside and outside
Area II. Fishing effort in Area II was twice as great as that outside the
area. Within Area II, the majority of tows were made in the northwest corner
of the area and along the north-south boundary separating the expanded area from
the original area of Area II. Fishing effort was also high along the U.S.-Canadian
maritime boundary. Effort outside Area II was dispersed with no clear concentrations.
Within Area II, catches from observed
tows totaled 474,491 lb. Catches of the 13 groundfish species covered
by the Northeast Multispecies Fishery Management Plan (hereafter referred to
as “groundfish
FMP species”) constituted 70% (333,366 lb) of the Area II total. Haddock
catches (60,934 lb) accounted for 13% of total catches and 18% of the catch
of groundfish FMP species. Atlantic cod was the dominant species taken
in Area II, accounting for 34% (161,997 lb) of total catches and 49% of groundfish
FMP catches.
Outside Area II, observed catches
totaled 135,250 lb, of which 66% were groundfish FMP species (88,875 lb)
and 6% were haddock (8098 lb).
Catch rates, expressed as catch per
unit of effort (CPUE; lb/hr fished), in Area II were considerably higher
than those outside the area. Haddock CPUE was 205% greater inside Area
II than outside. CPUEs within Area II were also higher for yellowtail
flounder (178%), American plaice (95%), winter flounder (68%), Atlantic cod
(39%), pollock
(31%), ocean pout (30%), windowpane (25%), and red hake (25%). Of
the 13 groundfish FMP species, only witch flounder, Acadian redfish, white
hake,
and
silver hake CPUEs were higher outside Area II than inside.
During January-March,
haddock catches in Area II were low, accounting for less than 2% of total
catches in the
area. During
April-June, however, haddock accounted for 16% of total catches in Area
II; in May and June (when haddock catches and CPUE peaked), haddock accounted
for 34%
of total catches in Area II and 46% of groundfish FMP catches. Had
an open fishery for mixed groundfish been conducted in the expanded portion
of Area II
during April-June, total haddock catches would have been extremely high. The
largest individual tows of haddock occurred in late June, indicating
that haddock were still aggregated in early summer.
Length-frequency
compositions of species
were similar inside and outside Area II, with discarding consistent with
prevailing minimum size regulations or market demand. For haddock, however,
large mature fish (>23 inches) constituted a greater proportion of catches inside
Area II than outside.
Given that Atlantic cod and haddock
together accounted for nearly half (47%) of the total experimental
fishery catches in the expanded portion of Area II, and that both of
these stocks on
Georges
Bank are presently at record-low levels of abundance, maintaining the
enlarged Area II seasonal closure in 1995 (and thereafter) is prudent as one
component
of a suite of conservation measures aimed at eliminating the overfished
conditions of these stocks.
INTRODUCTION
Since
1970, a seasonal closure of the northeast corner of Georges Bank has
been implemented to protect spawning concentrations of haddock. This
spawning area closure (originally designated as Area B, but subsequently
referred to as Area II) was first enacted by the International Commission
for the Northwest Atlantic Fisheries (ICNAF) in March and April 1970
(Figure
1A). The closure prohibited “fishing with gear capable
of catching demersal species” (International Commission for the Northwest
Atlantic Fisheries 1969), and was designed to reduce haddock catches
and to supplement existing catch limitations by spreading catches throughout
the year (Halliday 1988). Fishermen’s support for such closures
has traditionally been very strong; in fact, enactment of the haddock
spawning closure in 1970 by ICNAF has been attributed to the insistence
of U.S. fishermen (Halliday 1988).
Both the United States and Canada
retained use of the ICNAF haddock spawning area fishery closures after extension
of fishery jurisdictions in 1977, with minor adjustments in gear restrictions
and closure duration (Clark et al. 1982). After 1971, duration of
the Area II closure was lengthened by both countries to include March-May. In
October 1984, delimitation of the U.S.-Canadian maritime boundary subdivided
Area II between the United States and Canada. Nonetheless, the Area II
closure has since been independently maintained by both countries with little
change. Since 1985, Canada has continued to close its sector of Area II
to fishing during March-May. Similar closures were enacted in U.S. Area
II waters in 1985 and 1986. In 1987, the United States--under provisions
of the Northeast Multispecies Fishery Management Plan (hereafter referred to
as the “groundfish FMP”)--lengthened the duration of the Area II closure to include
February-May. This 4-mo closure was maintained annually through 1993 in
the U.S. portion of Area II.
Effective 1 January 1994, a revised
U.S. management program was implemented for groundfish (i.e., Amendment
5 to the groundfish FMP). As one part of a suite of conservation measures
to “eliminate the overfished condition of the principal groundfish stocks” (New
England Fishery Management Council 1993), the Area II seasonal closure was extended
spatially and temporally. Area II was expanded by 20' longitude to the
west and 15' latitude to the south (Figure
1B), and the closure implemented for 6 mo, from 1 January through
30 June. Rationale for this time/area extension was to provide additional
protection to concentrations of haddock in the area, viz.
In the case of the expansion of Area II, significant landings
of haddock are reported from the area around the current [pre-1994]
boundary line and when the area is opened. There are reports
of illegal fishing just over the boundary during the closure. Haddock
that are aggregated to spawn in this area are extremely susceptible
to being targeted, particularly around the margins of the area and
upon the termination of the closure. Based onhistorical landings,
nearly one quarter of the total landings of haddock are caught within
the area included in the proposed expansion during the closure, and
about one third of haddock landings are caught within the expanded
area during January through June. Based on an analysis of the
fishing effort in the area and displacing that effort to other areas
in the region with the next-highest catch rates in the 1988-90 period,
the haddock that would have been saved amounts to 21% of the total
landings of haddock while the landings of other groundfish would have
increased by 1 percent. Without calculating for displaced effort,
the haddock savings would have amounted to 33 percent and other groundfish
species to about one percent of the total landings (Ham et al., 1991). (New
England Fishery Management Council 1993).
The 1994 regulations prohibited any fishing in Area II during the closure
period, except for vessels using pot gear to fish for American lobsters
and for vessels using dredges to catch sea scallops. Retention
of any haddock caught incidentally by scallop dredge vessels was not
permitted.
Concurrent with enactment of the expanded
Area II closure in 1994, an experimental fishery program was established. This
fishery was authorized as a research exemption under the groundfish FMP, and
allowed a restricted number of trawl vessels to fish in the newly-expanded, L-shaped
portion of Area II during the closure period, provided that scientific observers
were carried aboard the vessels. Purpose of the experimental fishery was
to monitor the catch and bycatch of Atlantic cod and haddock in the expanded
area during the January-June closure. Additional objectives were to: 1)
assess whether a limited trawl fishery for Atlantic cod (and other groundfish)
could be prosecuted in the expanded area without incurring significant bycatches
of haddock; and 2) determine when concentrations of spawning and post-spawning
haddock no longer resided in the expanded area.
In this report, we summarize
and evaluate the performance of the 1994 experimental fishery using tow-by-tow
data collected
by scientific observers placed aboard each vessel in the experiment. Information
is provided on total catches, total fishing effort, species composition, discarding
practices, size-frequency composition of the landings and discards, and spatial
and temporal trends in catch, effort, and CPUE. Attention is focused on
haddock and the 12 other species covered by the groundfish FMP (i.e., Atlantic
cod, pollock, yellowtail flounder, winter flounder, witch flounder, windowpane,
American plaice, Acadian redfish, white hake, red hake, silver hake, and ocean
pout), although data are provided on all species caught in the experimental fishery. Comparisons
by species and month are made between catches taken inside and outside
Area II. We also report the results of two sea sampling trips made
on Georges Bank in July 1994 after Area II was re-opened for fishing.
METHODS
DESIGN
AND CONDUCT OF THE EXPERIMENTAL FISHERY
The operational plan for
the experimental fishery required deployment of scientific observers
aboard commercial vessels authorized to fish in the expanded portion
of Area II. A limited number of trawl vessels were solicited to
participate voluntarily in the experiment. Vessel and observer
schedules were coordinated to ensure that all scientific data collection
needs would be met.
Industry participation was initiated
with inquiries to vessel owners and captains who had landed trips from the expanded
area during the preceding winter-spring season. Prospective participants
were briefed on the purpose, design, and administrative requirements of the experiment. All
vessels licensed to fish in the groundfish fishery, however, received written
notification in December 1993 that an experimental fishery would be conducted
and that participating vessels would be required to take approved observers and
submit logbooks. The number of participants in the experimental fishery
were limited to those required to keep pace with the scheduled 2-4 trips per
month.
Once a vessel was selected to participate
in the experimental fishery, an “Experimental Fishing Certificate for the Expanded
Portion of Closed Area II” was issued and arrangements made to provide observer
coverage. The certificate was hand-delivered to the vessel captain, at
which time the objectives and procedures of the experimental fishery program
were discussed. Any questions or concerns on the part of the captain or
crew were addressed. While fishing in the experimental area, each participating
captain agreed to the following conditions:
- The vessel could fish anywhere within the expanded closed area, but
not within the inner triangle portion constituting the original Area
II. Within the L-shaped expanded area, the captain was free to
decide where and when to fish. No restrictions were placed on
the number of tows or how fishing operations should be conducted. However,
each captain was informed that broad coverage of the expanded area
would be beneficial in providing a synoptic basis for analyzing the
experimental fishery data.
- Vessels could fish only with regulated mesh [i.e., 5.5 inches
(13.97 cm) during January-March, 6.0 inches (15.24 cm) from April onward].
- Catches of Atlantic cod, American plaice, pollock, Acadian redfish,
winter flounder, witch flounder, and yellowtail flounder of legal size
could be landed, but no haddock could be retained.
- The vessel had to be accompanied by a National MarineFisheries Service
(NMFS)-approved observer.
- Vessels were under no obligation to remain in the experimental area
for the entire trip.
- An experimental fishery certificate was issued and valid for a single
trip. If a vessel wished to make a subsequent trip in the experimental
fishery program, a new certificate had to be issued.
As word of the experimental
fishery spread through the industry, vessel owners and captains contacted
NMFS requesting details on the experiment and expressing interest in
participation. In the few cases where the number of interested
vessels exceeded the available observer coverage, vessels were selected
randomly.
All scientific observers were provided
by the Northeast Fisheries Science Center (NEFSC) Fisheries Observer Program. Observers
were instructed to observe as many hauls as possible and, for each haul, record
data on fishing location, fishing effort, catches, discards, gear characteristics,
hydrographic information, and other information as specified in the “NEFSC Observer
Manual.” Additionally, observers were requested to obtain length-frequency
samples from haddock and other groundfish FMP species.
Cooperation at sea was generally excellent
between vessel operators and scientific observers. In addition to providing
all required data, many captains and crew members provided additional anecdotal
information on vessel operations and the status and management of the groundfish
fishery.
DATA PROCESSING AND ANALYSIS
Copies of the tow-by-tow
logbooks completed by the scientific observers on each trip in the experimental
fishery were forwarded to the NEFSC Woods Hole Laboratory for review
and analysis. Data analyses included: 1) tow-by-tow summaries
of fishing effort and catches (i.e., both retained and discarded)
by species or species group; 2) trip summaries of the tow-by-tow locations
(i.e., inside or outside Area II) where fishing occurred; 3) month/location
summaries of catches, effort, and CPUE; and 4) location summaries of
the size frequencies of landings and discard samples. Spatial and
temporal patterns in fishing effort, catches, and CPUE were evaluated
by month. CPUE was expressed as catch per time fished (lb/hr),
discard rates as percentages, and size frequencies as mean, maximum,
and minimum lengths (cm). In calculating CPUE, no adjustments were
made for possible differences in fishing power among vessels.
Tows were assigned to Area II if all,
or any part, of the tow was made inside Area II. Tows made outside Area
II were collectively analyzed as a single group, although these hauls were made
over a very wide geographical area. Comparisons of catches, species composition,
and CPUE from tows made inside and outside Area II were conducted to provide
initial insight on the impacts of the Area II closure in protecting haddock and
other groundfish FMP species. More refined geographical-information-system-type
analyses, however, are required to delineate finer-scale spatial patterns, both
within Area II and between Area II and external (both adjacent and more distant)
areas.
RESULTS
EXPERIMENT-WIDE
Table
1 lists the common and scientific names of all species caught during
the January-June 1994 experimental fishery. During the fishery,
14 trips were made by 12 different vessels (Table
2). Participating vessels were from the Massachusetts ports
of Boston (1), Gloucester (6), and New Bedford (2), and from the Maine
ports of Portland (2) and Rockland (1). Vessels were absent from
port for a total of 137 days, fished (i.e., gear on bottom)
1882 hr (78.4 days), and made 522 tows. Average trip duration
was 9.8 days (with a range of 9-13 days), average fishing time per
trip was 134 hr (with a range of 62-186 hr), average number of tows
per trip was 37 (with a range of 20-58), and average tow duration was
3.6 hr (with a range of 2.1-4.8 hr).
All trips but one (i.e., trip
10) fished both inside and outside Area II (Table 2; Figure
2). Total catches, discards, fishing effort, number of tows, and haddock
CPUE for the entire experiment are summarized by location in Table
3, Table 4 and Table 5;
individual trip data are presented in Table
6, Table 7 and Table 8. Of
the 522 tows made during the experiment, 445 tows (85%) were observed by scientific
observers (Table
3). Sixty-nine percent (305) of the observed tows occurred inside Area
II, and 31% (140) outside Area II. Observed tows accounted for 90% of total
hauls in Area II, and 76% of total hauls made outside Area II. Retained
catches were recorded by scientific observers for all hauls (i.e., observed
and unobserved), but discards could only be tallied in observed hauls. Fishing
captains do not normally maintain records of discards. Therefore, discard
estimates are not available from unobserved tows. Accordingly, all results
subsequently presented are based solely on observed hauls.
Experiment-wide catches totaled 609,741
lb [276.6 metric tons (mt)], of which 422,241 lb (191.5 mt) were groundfish
FMP species (69%) and 69,032 lb (31.3 mt) were haddock (Table
3). Haddock accounted for 11.3% of total catches and 16.3% of groundfish
FMP catches. Although total observed fishing effort inside Area II, in
terms of both number of tows and hours fished, was twice as great as outside
Area II, total Area II catches were 251% higher (474,491 versus 135,250 lb),
groundfish FMP catches 275% higher (333,366 versus 88,875 lb), and haddock catches
652% higher (60,934 versus 8098 lb) than outside Area II (Table
4). While groundfish FMP species accounted for about the same percentage
of total catches in both areas (i.e., 70% inside Area II, 66% outside
Area II), haddock accounted for 18.3% of groundfish FMP catches inside Area
II and 9.1% outside Area II (Table
3). For the January-June period, haddock CPUE inside Area II was 205%
higher than outside Area II (53.1 versus 17.4 lb/hr; Table
5).
Nearly all (96%) caught haddock were
discarded (Table 3). Within Area II, this was due to the experimental fishery
requirement that any caught haddock could not be retained (although haddock were
inadvertently retained on three tows inside Area II due to a misunderstanding
that haddock could be retained if a tow was not completely within Area II). Outside
Area II, retention of haddock was legally restricted to 500 lb (227 kg)
per trip.
Discards of all species combined amounted
to 206,867 lb (93.8 mt), of which groundfish FMP species constituted
37% (75,845 lb; 34.4 mt) (Table
3). Haddock discards (66,052 lb; 30.0 mt) accounted for 32% of total
discards and 87% of groundfish FMP discards. Other species heavily discarded
included skates (100,736 lb; 45.7 mt) and spiny dogfish (19,422 lb; 8.8 mt) (Table
4). Together with haddock, these species accounted for 90%
of the total biomass of fish discarded.
En route to the fishing grounds, vessel
captains were asked to identify the species targeted for fishing. Atlantic
cod was designated as the target in nine trips, “mixed groundfish” in four trips,
and pollock in one trip (Table
6). Trip catches were consistent with these designations (Table
6, Table 7,
and Table 8). Atlantic
cod accounted for 34% of total catches during the experiment, and 50% of catches
of groundfish FMP species (Table
6). Captains generally fished according to the “style” of their port, i.e.,
Gloucester vessels fished for a mix of groundfish, New Bedford vessels
fished for Atlantic cod and various flounders, and Maine vessels fished
for Atlantic
cod, pollock, and American plaice.
Nearly 50 different species were caught
during the experimental fishery (Table
1). Relative contributions (as percent by weight) of individual species
to the total experiment-wide catch of 609,741 lb were as follows: Atlantic
cod (34%), skates (19%), pollock (12%), haddock (11%), goosefish (5%), American
plaice (3%), yellowtail flounder (3%), spiny dogfish (3%), white hake (2%), “other
fishes” (1%; see Table
1 for the 23 species constituting this category), cusk (1%), witch
flounder (1%), American lobster (1%), winter flounder (1%), ocean pout
(1%), Atlantic
wolf-fish (<1%), Acadian redfish (<1%), silver hake (<1%), red hake
(<1%), “other invertebrates” (<1%; see Table
1 for the eight species constituting this category), and windowpane
(<1%)
(Table
4). Additionally, two Atlantic white-sided dolphin (Lagen-orhynchus acutus)
were incidentally captured during one of the trips and returned to the
sea. No
other marine mammals, sea turtles, or sea birds were caught during the experiment.
INSIDE AREA II
Within Area II, catches from
the 304 observed tows (1148 fishing hr) totaled 474,491 lb (215.2 mt),
of which 302,634 lb (137.3 mt) were retained (64%) and 171,857 lb (78.0
mt) were discarded (Table
9, Table 10, Table 11). Fishing
activity occurred in all 6 mo, but was not evenly distributed in time
or space. Experimental fishing effort was lowest in January (15
observed tows; 72 hr fished), intermediate during February and May (32
and 37 tows; 76 and 110 hr fished), and highest in March, April, and
June (61-97 tows; 230-422 hr fished) (Table
9). The majority of tows were made in the northwest corner
of the expanded area (Figure
3). During March-June, fishing was concentrated along the north-south
boundary separating the expanded area from the original area of Area
II, and also along the U.S.-Canadian maritime boundary (i.e.,
Hague Line). In the first few months of the experiment, vessels
moved throughout the expanded area to locate target species; in the last
three months, some vessels towed in locations where it was felt haddock
could be avoided.
Groundfish FMP catches (333,366 lb;
151.2 mt) constituted 70.3% of total catches in Area II, and 88.3% (267,120
lb; 121.2 mt) of retained catches in Area II (Table
9 and Table 10). Atlantic
cod was the most-caught species (161,997 lb; 73.5 mt), accounting for 34% of
the Area II total catch and 49% of the Area II groundfish FMP catch. Haddock
catches in Area II totaled 60,934 lb (26.7 mt), 12.8% of Area II total catches
and 18.3% of Area II groundfish FMP catches. All but 2% (1071 lb) of
the caught haddock were subsequently discarded (Table
12).
Prior to April, haddock catches in
Area II were minor (i.e., January-March total of 1968 lb), accounting
for less than 3% of Area II total catches per month and less than 4% of groundfish
FMP catches per month (Table
9). Average catch per tow of haddock during January-March was only
18.2 lb (i.e., January -- 12.0 lb; February -- 0.3 lb; and March --
29.2 lb); in these months, haddock CPUE averaged just 5.2 lb/hr (i.e.,
January -- 2.5 lb/hr; February -- 0.1 lb/hr; and March -- 7.7 lb/hr) (Figure
4). The largest catch of haddock taken in any one tow during these
3 mo was 407 lb (Table 6). Apart from this tow and another tow in which
102 lb of haddock were caught, none of remaining 106 observed tows during
January-March in Area II caught more than 78 lb of haddock (Figure 5).
Beginning
in April and continuing
through May, haddock CPUE markedly increased in every trip made in Area
II, rising from 50 lb/tow (10.5 lb/hr) in trip 8 to 669 lb/tow (186 lb/hr)
in
trip 12 (Table
7). Average haddock catch per tow was 130 lb/tow (30 lb/hr) in
April and 577 lb/tow (194 lb/hr) in May (Table
9; Figure
4). During these 2 mo, catches of haddock exceeded 100 lb in 51
of the 134 observed tows (38%), and exceeded 500 lb in 17 tows. Tows
with the highest haddock catches occurred in the northwest corner of the
expanded
area (near the 50-fathom contour) and along/near the north-south boundary
of the original and expanded closed areas (Figure
5). The largest catch of haddock taken in a single tow during
April and May was 4600 lb -- more than twice the total haddock caught in
Area II
during the first 3 mo of the experimental fishery.
In June, haddock CPUE declined to
105 lb/hr (396.7 lb/tow)--lower than in May but substantially higher
than any other month (Figure
4). The last trip in the experimental fishery made in June
(i.e.,
trip 14) also fished on 1 July, the first day that all of Area II was
re-opened. On
this date, three observed tows were made in the inner triangle of original
Area II. Two large hauls of haddock were taken (9000 and 3500 lb),
indicating that high concentrations of haddock still existed in the re-opened
area.
Over the entire January-June period,
87 of the 305 observed tows (28%) in Area II caught no haddock, and in
114 other tows (37%) haddock catches were 50 lb or less (Table
13). Overall, 93% of Area II hauls (284 tows) caught less than
500 lb (227 kg) of haddock.
Spatial distributions of haddock
catches per tow by month are presented in Figure 5. Similar distributions
of catch per tow are presented for Atlantic cod (Figure
6), flounders (yellowtail [Figure
7], winter [Figure
8], American plaice [Figure
9], and witch [Figure
10]), white hake (Figure
11), and goosefish (Figure
12) in Figures 6-12. Spatially, these relative density distributions
are consistent with those observed in recent NEFSC spring research vessel
bottom trawl surveys.
After Atlantic cod (which accounted
for 34% of Area II catch), the most-caught species were skates (20%),
haddock (13%), pollock (12%), yellowtail flounder (4%), goosefish (4%),
American
plaice (4%), and spiny dogfish (3%) (Table
9). However, the relative contributions of these species to the overall
retained catch were quite different, as 90% of the skates (84,159 lb; 38.2 mt)
and all spiny dogfish (13,672 lb; 6.2 mt) were discarded (Table
11 and Table 12). As
a result, Atlantic cod accounted for 53% of retained catches, pollock for 18%,
yellowtail flounder and goosefish for 6% each, and American plaice for 5% (Table
10). The groundfish FMP species accounted for 88% of retained
catches in Area II.
Fish were discarded for three main
reasons. Haddock caught in Area II could not retained under provisions
governing the experimental fishery. Spiny dogfish, ocean pout, skates,
other fishes, and other invertebrates were heavily discarded (i.e.,
90% discard rates; Table
12) due to the limited market value of these species to the vessels
in the experiment. For the remaining species, discards generally reflected culling
of undersized fish due to market considerations or existing legal minimum-size
restrictions.
OUTSIDE AREA II
Catches, landings, and discards
taken outside Area II during the experimental fishery are summarized
by species or species groups in Table
14, Table 15 and Table 16,
respectively. Catches by trip are presented in Table
8. A total of 140 tows were observed, comprising 466.2 hr of
fishing effort. Expectedly, the temporal distribution of fishing
activity outside Area II differed from that inside Area II as the vessels
in the experimental fishery differentially allocated their fishing activities
between the two areas. Fishing effort outside Area II was lowest
in April (5 tows; 19 hr fished) (Table
14) when fishing effort inside Area II was highest (Table
9). Highest fishing effort outside Area II occurred in March
(53 tows; 167 hr) and May (36 tows; 126 hr); during these 2 mo, effort
inside Area II was similar, indicating that vessels divided their fishing
activities nearly equally between the two areas.
Catches in observed tows made outside
Area II totaled 135,250 lb (61.3 mt), of which 66% (88,875 lb; 40.3 mt) were
groundfish FMP species and 6% (8098 lb; 3.7 mt) were haddock (Tables 9 and
14). More
than 75% (6189 lb; 2.8 mt) of caught haddock were discarded (Table
16). As in Area II, Atlantic cod was the predominant species caught
(47,272 lb; 21.4 mt), accounting for 35% of total catch and 53% of groundfish
FMP catch.
Haddock catches outside Area II did
not exceed 500 lb per trip in the first 11 trips of the experiment (i.e.,
trips between January and mid-May; Table
8). In these first 11 trips, haddock catches accounted for about 2%
(with a range of 0-9.6%) of total catches taken in trips outside Area II, and
about 2.4% (with a range of 0-10.2%) of groundfish FMP catches taken in trips
outside Area II (Table
8).
On a monthly basis, haddock catches
accounted for less than 4% of total catches outside Area II during January-May
(Table
14). Apart from April when haddock CPUE seemingly increased (i.e.,
to 16.5 lb/hr, although this is based on only five observed tows), haddock
CPUE prior to June was extremely low (i.e., <6.9 lb/hr; <24 lb/tow) (Table
14). In June, haddock catches and haddock CPUE outside Area II sharply
increased (Table 14; Figure
4); more haddock were caught in June (5759 lb) that in the first 5
mo combined (2339 lb). This increase was due to two large hauls (3500
and 1000 lb) of haddock in June made just outside the Area II boundary.
Of the 140 observed tows made outside
Area II during the experiment, 44% (61 tows) contained no haddock, and
40% (56 tows) contained haddock catches of 50 lb or less (Table
13). In only two tows did haddock catches outside Area II exceed 500
lb (i.e., the June tows mentioned above).
Species composition of catches made
outside Area II was similar to that inside Area II. Atlantic cod accounted
for 35% of total catches, followed by skates (15%), pollock (13%), goosefish
(9%), haddock (6%), spiny dogfish (4%), white hake (4%), and American plaice
(3%) (Table
14). Of retained catches, Atlantic cod accounted for 47%, pollock for
17%, goosefish for 12%, and white hake for 5% (Table
15). Since discarding practices outside Area II were nearly identical
to those inside Area II, species discard percentages were also similar (Table
12 and Table 17).
POST-EXPERIMENT SEA SAMPLING TRIPS TO
GEORGES BANK
On 1 July, the entirety of
Area II (i.e., both the expanded area and the inner triangle)
was re-opened for fishing. To assess post-opening catch rates of
haddock and other groundfish FMP species, observers were placed on two
vessels that intended to fish in the Area II region. Both trips
sailed in mid-July and were absent from port for 10-11 days (Table
2). One of the trips (i.e, trip 15) fished completely outside
Area II, targetingAtlantic cod and flounders; the other trip (i.e.,
trip 16) fished completely inside Area II, targeting yellowtail flounder
(Figure
13).
Within Area II, 37 of the 48 post-experiment
tows (77%) were observed (Table
18); haddock catches in these hauls amounted to only 22 lb, and constituted
less than 1% of the total catch (24,792 lb; 11.2 mt). Haddock catches were
negligible primarily because the vessel used a trawl designed for catching flatfish. As
intended, yellowtail flounder was the principal species caught during the trip,
accounting for 45% (11,331 lb; 5.1 mt) of total catch and 77% (10,192 lb; 4.6
mt) of retained catch (Table
19). Most yellowtail flounder catches were taken in the inner triangular
section of Area II (Figure
14). Large quantities (10,178 lb; 4.6 mt) of skates were also caught,
but 90% were discarded.
In the July trip that fished outside
Area II, 36 of 40 tows (90%) were observed (Table
18). Groundfish FMP species accounted for 66% (12,410 lb; 5.6 mt) of
total catch (18,877 lb; 8.6 mt), with Atlantic cod and American plaice each accounting
for 20% of the total (Table
19). Haddock catches totaled 798 lb, or 4% of total catch and 6% of
groundfish FMP catch. Approximately 25% of the total trip catch was discarded,
consisting mostly of spiny dogfish and skates.
SIZE COMPOSITION OF EXPERIMENTAL FISHERY
CATCHES
During the January-June experimental
fishery, 9430 length-frequency measurements were made on 13 species. Samples
were taken inside and outside Area II from both retained catches and
discards. Most sampling (9408 fish) focused on nine groundfish
FMP species and goosefish (Table
20); sampling of three additional species was insignificant (i.e.,
15 Atlantic halibut, 5 American lobster, and 2 American shad).
Sampling of haddock was the top priority. A
total of 4801 haddock were measured, constituting 51% of all sampled fish. Within
Area II, length frequencies were taken from 3968 haddock (3884 discards; 84 retained);
outside Area II, length frequencies were taken from 833 haddock (564 discards;
269 retained) (Figure
15). Size range of haddock discarded in both areas was similar (Table
20), but large haddock (>60 cm) constituted a greater proportion of discards
inside Area II than outside Area II. Since, in both areas, nearly all caught
haddock had to be discarded [i.e., culling was not much affected by
the minimum legal size of 19 inches (48 cm)], the larger size composition of
Area
II discards indicates that older, mature haddock were proportionally more dominant
inside Area II than outside.
For Atlantic cod, the principal species
caught in both areas, size-frequency distributions of catches inside and
outside Area II were virtually identical (Table
20; Figure
16). Discarded fish ranged from 37 to 49 cm (14.6-19.3 inches), and
averaged about 42 cm (16.5 inches); retained fish ranged from 47 to 117 cm (18.5-46.1
inches), and averaged about 70 cm (27.6 inches). The lack of overlap
in sizes between discarded and retained fish reflects culling in accord with
the
legal minimum size of 48 cm (19 inches) for Atlantic cod.
Size-frequency plots for the other
eight species sampled (i.e., yellowtail flounder [Figure
17], pollock [Figure
18], winter and witch flounder [Figure
19], American plaice [Figure
20], windowpane [Figure
21], white hake [Figure
22], and goosefish [Figure
23]) are presented in Figures 17-23. In general, size compositions
were similar inside and outside Area II, with culling consistent with prevailing
minimum-size regulations--in the cases where these exist--or marketing demands. Of
course, presence of scientific observers aboard the experimental fishery vessels
may have affected culling practices, particularly for species regulated by minimum-size
restrictions.
IMPACT OF AREA II CLOSURE ON HADDOCK
AND OTHER GROUNDFISH FMP SPECIES
Enlargement of Area II in
1994 was enacted to ensure the protection of haddock from fishing during
the spawning season when they become concentrated. The closure
period was also lengthened in time to include January to ensure that
haddock beginning to aggregate in the area would be provided the fullest
protection.
One approach to evaluate the protection
afforded to haddock and other groundfish FMP species by the expanded Area II
closure is to examine the experimental fishery catch rates inside the expanded
portion of Area II with those outside Area II. Higher catch rates generally
reflect higher densities of fish. Hence, to the extent that catch rates
inside the expanded portion of Area II are higher than those outside, the absence
of a fishery inside the expanded portion will generate considerable “savings” of
fish.
The CPUE -- retained and discard catches
combined -- inside Area II was higher than outside Area II for: 1) all
species combined (413 versus 290 lb/hr); 2) total groundfish FMP species (290
versus 191 lb/hr); and 3) for nine of the 13 groundfish FMP species. The
CPUE inside Area II was higher for haddock (205%), yellowtail flounder (178%),
American plaice (95%), winter flounder (68%), Atlantic cod (39%), pollock (31%),
ocean pout (30%), windowpane (25%), and red hake (25%). For the remaining
four groundfish FMP species, the CPUE inside Area II was lower: witch
flounder (15%), white hake (27%), silver hake (43%), and Acadian redfish (96%)
(Table
5 and Figure
24).
During January-March, haddock CPUE
both inside and outside Area II was very low (<8 lb/hr) (Table
9 and Table 14; Figure
4). In April and May, haddock CPUE within Area II was substantially
higher than outside (April -- 30 versus 17 lb/tow; May -- 194 versus 7 lb/tow). In
June, haddock CPUE in both areas exceeded 100 lb/hr. As previously
mentioned, the high haddock CPUE in June outside Area II was due to two
large catches just
outside the Area II boundary.
Within Area II, CPUEs of Atlantic
cod and of all groundfish FMP species excluding haddock and Atlantic
cod peaked in April, and were higher than those for haddock in each month
but
May and
June (Figure
4). Outside Area II, Atlantic cod CPUE peaked in March and
was higher than haddock CPUE in all months but June.
For species and
species groups other
than groundfish FMP species taken in the experimental fishery, CPUEs
inside Area II were generally the same or higher than those outside Area
II, except for goosefish
(15.2 versus 25.8 lb/hr), spiny dogfish (11.9 versus 12.3 lb/hr), cusk
(4.1 versus 4.9 lb/hr), American lobster (3.3 versus 3.4 lb/hr), Atlantic
wolffish (0.4 versus
3.3 lb/hr), and other invertebrates (0.2 versus 1.2 lb/hr) (Table
5).
In total, the generally higher CPUEs
inside the expanded portion of Area II compared to those outside Area
II suggest that fish densities were higher inside the expanded area. Prohibiting
a commercial fishery in the expanded area in 1994 therefore prevented
high concentrations
of fish from being exploited.
DISCUSSION
Some
commercial fishermen have taken the position that it is possible to prosecute
a fishery for mixed groundfish in the expanded portion of Area II without
catching significant quantities of haddock. This position was,
in part, the basis for conducting the experimental fishery, the purpose
of which was to monitor the catch and bycatch of Atlantic cod and haddock
in the expanded portion of Area II during January-June 1994.
During January
through March, haddock catches in the expanded area were low (1968 lb
in total), accounting for less
than 2% of total Area II catches. During this same period, 60,478 lb of
other groundfish FMP species were taken in the expanded area. Clearly,
fishing in these months had little negative impact on haddock.
However, during
April-June, haddock constituted 16% of total catches, and 22% of groundfish
FMP catches, in Area
II. In May and June when haddock catches and CPUE were at their highest
in Area II, haddock constituted 34% of total catches and 46% of groundfish
FMP catches. Obviously, had an open fishery for mixed groundfish been
conducted in the expanded area during April-June, total haddock catches would
have been
extremely high.
Traditionally, the period of peak
haddock spawning on the northeastern part of Georges Bank is during March
and April (Overholtz 1987). However, the timing and duration
of spawning can vary from year to year due to influence of temperature. In
1994, high concentrations of haddock (i.e., >400 lb/tow) were
not detected in the experimental fishery until mid-March, suggesting
that haddock spawning
occurred
later in 1994 than the traditional pattern. Catches of haddock in tows
made in Area II in late June were among the highest observed in the experiment,
indicating that haddock were still aggregated in early summer.
After 1 July
when Area II was re-opened for fishing, large catches of haddock inside
Area II were reported by commercial
fishermen. Observations made from two sea sampling trips conducted
in mid-July, however, did not substantiate the existence of large concentrations
of haddock
-- although haddock may have already dispersed by this time. Also,
the fishing gear used in the July sea sampling trip to Area II was not
optimal for
catching haddock.
Since haddock caught inside Area II
could not be retained, several vessels in the experimental fishery moved
to different fishing locations after haddock were caught. These movements
were likely intended to avoid subsequent haddock catches and to reduce culling
time. Large
haddock catches taken during the last few trips in the experimental fishery
prompted some vessel captains to suggest that the closure period should be
extended further
into the summer.
Haddock and Atlantic cod accounted
for 13 and 34%, respectively, of total catches inside Area II. As
a group, the 13 groundfish FMP species accounted for 70% of total catches
inside Area
II. Area II catches were thus dominated by species regulated under
the Northeast Multispecies Fishery Management Plan. Haddock, Atlantic
cod, and yellowtail flounder on Georges Bank are at record-low abundance
levels; the
haddock and yellowtail flounder stocks have “collapsed,” and an imminent
danger exists that the Georges Bank Atlantic cod stock will soon collapse
(Northeast
Fisheries Science Center 1994). Given that these three species
constituted a major fraction of monthly catches inside Area II during
the January-June 1994
experimental fishery, maintaining the enlarged Area II seasonal closure
in 1995 (and thereafter) is prudent as one component of the suite of
conservation measures
aimed at eliminating the overfished conditions of these stocks.
ACKNOWLEDGMENTS
We
extend our gratitude and appreciation to all scientific observers who
collected the experimental fishery data. We also thank the captains,
vessel owners, and crews who participated in the 1994 experiment.
REFERENCES
CITED
Clark, S.H.; Overholtz, W.J.;
Hennemuth, R.C. 1982. Review and assessment of the
Georges Bank and Gulf of Maine haddock fishery. J. Northwest
Atl. Fish. Sci. 3:1-27.
Halliday, R.G. 1988. Use of seasonal spawning area
closures in the management of haddock fisheries in the Northwest
Atlantic. Northwest Atl. Fish. Organ. Sci. Counc. Stud.
12:27-36.
Ham, D.; Mannesto, G.; Wang, S. 1991. Haddock spawning
closed area analysis--a summary. A report for the Multispecies
Plan Development Team of the New England [Fishery Management]
Council. Gloucester, MA: NMFS Northeast Regional Operations
Office.
International Commission for the Northwest Atlantic Fisheries. 1969. Report
of the 19th annual meeting, 2-7 June 1969. Int. Comm.
Northwest Atl. Fish. Annu. Proc. 19:14-39.
New England Fishery Management Council. 1993. Amendment
#5 to the Northeast Multispecies Fishery Management Plan. Saugus,
MA: New England Fishery Management Council.
Northeast Fisheries Science Center. 1994. Report
of the 18th Northeast Regional Stock Assessment Workshop (18th
SAW): the plenary. Northeast Fish. Sci. Cent. Ref. Doc.
94-23: 71 p. Available from: National Marine Fisheries
Service, 166 Water St., Woods Hole, MA 02543.
Overholtz, W.J. 1987. Factors relating to the reproductive
biology of Georges Bank haddock (Melanogrammus aeglefinus)
in 1977-83. J. Northwest Atl. Fish. Sci. 7:145-154.
