Maritimes Region Stock Status Report A3-35(2002) December 2002 Updates on Selected Scotian Shelf Groundfish Stocks in 2002 Cod on the Eastern Scotian Shelf (Div. 4VsW) ................................................................. 4 Pollock in Div. 4VWX + 5Zc ............................................................................................... 7 Silver Hake on the Scotian Shelf (Div. 4VWX) ................................................................. 12 Unit 3 Redfish ................................................................................................................... 16 Witch Flounder on the Scotian Shelf (Div. 4VWX) ........................................................... 21 American Plaice, Yellowtail Flounder, and Winter Flounder on the Western Scotian Shelf (Div. 4X) ................................................................................ 24 Cusk on the Scotian Shelf (Div. 4VWX) ........................................................................... 27
Transcript
Maritimes Region Stock Status Report A3-35(2002)
December 2002
Updates on Selected Scotian ShelfGroundfish Stocks in 2002
Cod on the Eastern Scotian Shelf (Div. 4VsW) ................................................................. 4
Pollock in Div. 4VWX + 5Zc............................................................................................... 7
Silver Hake on the Scotian Shelf (Div. 4VWX) .................................................................12
Unit 3 Redfish ...................................................................................................................16
Witch Flounder on the Scotian Shelf (Div. 4VWX) ...........................................................21
American Plaice, Yellowtail Flounder, and Winter Flounder on the
Western Scotian Shelf (Div. 4X) ................................................................................24
Cusk on the Scotian Shelf (Div. 4VWX) ...........................................................................27
Maritimes Region Summary
2
Updates on Selected Scotian ShelfGroundfish Stocks in 2002
Background
This report provides an update of stock statusbased on recent fishery and survey data of thefollowing stocks: cod on the eastern ScotianShelf (Div. 4VsW), pollock in Divs. 4VWX+5Zc,silver hake on the Scotian Shelf (Div. 4VWX),Unit 3 redfish, witch flounder on the Scotian Shelf(Div. 4VWX), American plaice, yellowtail flounder,and winter flounder on the western Scotian Shelf(Div. 4X), and cusk on the Scotian Shelf (Div.4VWX). The SSR reference for the last fullassessment of each stock is listed under the“Background” section of each update.
In 2002, assessments of the following stocks;4Vn cod (SSR A3-02), 4X cod (SSR A3-05),4TVW haddock (SSR A3-06), 4X haddock (SSRA3-07) 4VW American plaice, yellowtail flounderand winter flounder (SSR A3-34), 4VWX whitehake (SSR A3-10), 4VsW winter skate (SSR A3-29), 4VWX monkfish (SSR A3-30), and 4VWXwolffish (SSR A3-31) were also conducted.
4X 4W 4Vs
4T4Vn 3Ps
3Pn
SA5
Summary
• For 4VsW cod, the three survey series all indicate continuing low and decliningabundance and have not indicated any major recruitment events in recent years.Until recruitment of several large year-classes is seen, there does not appear to beany basis to expect stock growth.
• For 4VWX5Zc pollock, the 1997 year-class is stronger than the recent average andthat there are preliminary indications that the 1998 and 1999 year-classes may alsobe above the recent average. However, the fishery remains spatially constricted,and the abundance of large fish remains low. The rapid increase in catch rates from2001 to 2002 is probably due, in part, to increased availability. Catches up to thelevel of the 2002 TAC will likely permit rebuilding of the resource, and should resultin a reduction in exploitation rate.
• For 4VWX silver hake, the resource status continues to be poor and may beworsening.
• Unit 3 redfish population biomass estimates, although variable, have not changedmuch and should result in fishing and stock conditions in 2003/04 being much the
Maritimes Region Summary
3
same as in recent years. However, there is evidence that the period of improvedrecruitment may be over, which would have consequences for yield in the mediumterm.
• For witch flounder, biomass remains low. However, the strong year-classes(<15cm) from 1994-1999 have produced good signs of improved recruitment cominginto the fishable population (>35cm) in the near future.
• The lack of adequate information regarding species identification of landings coveredby the generic 4X flatfish TAC is a major constraint to conducting assessments of thethree separate stocks within the single management unit. Current survey informationon Western Scotian Shelf flatfish indicates a very mixed set of stock status scenarios- a worsening situation for American plaice, an improving situation for yellowtailflounder, and relative stability in stock status of winter flounder.
• For cusk, despite the recent introduction of catch controls, this is a stock whichshows no signs of improvement. While the factors affecting the populationabundance of cusk are not well understood, it is possible that the 1000t cap placedon this stock is not providing adequate restrictions on catches to allow for the stockto rebuild and more restrictive measures may be required.
Maritimes Region 4VsW Cod
4
Cod on the Eastern ScotianShelf (Div. 4VsW)
Background
The cod (Gadus morhua) resource on theEastern Scotian Shelf is a complex of spawningcomponents including at least two major offshoregroups (Western/Sable and Banquereau), smalleroffshore groups (Middle Bank, Canso Bank) anda chain of smaller coastal spawning groups. Thesituation is complicated by the presence of bothspring and fall spawning in several of thespawning components (Sable/Western offshoreand various inshore areas).
Growth rates differ between 4Vs and 4W so thatin the 1970s, fish in 4Vs reached 68cm at age 7while in 4W reached 72cm. In the mid-1980s,growth declined in both areas and the averagelength at age 7 dropped to 59 and 54 cmrespectively from 1985 to 1995.
The fishery for 4VsW cod was prosecutedprimarily by foreign vessels until the extension ofjurisdiction in 1977. Since that time, theCanadian offshore trawler fleet accounted for70-75% of the landings and longliners most ofthe rest. Catches from 1958-79 were about 40-50% from 4Vs, however, as the stocks rebuilt inthe early 1980s, the fishery shifted more to theeast each year and 4Vs accounted for 60-80%of the landings from 1980-93.
The most recent assessment of thisstock was conducted in spring 1998(DFO 1998). Annual updates havebeen conducted since, the most recentbeing DFO (2001). More recentinformation from the fishery, researchvessel and sentinel surveys is presentedin this update.
1. By-catch only.2. By-catch and commercial index.3. Fishing year, landings and TAC refer to the 15
month period from January 1, 1999 to March 31,2000.
4. Commencing in 2000, fishing year, landings andTAC refer to the period April 1st of the current yearto March 31st of the following year.
Landings, tonnes
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
1962 1967 1972 1977 1982 1987 1992 1997 2002
SUBDIV. 4Vs DIV. 4W
TAC
The 4VsW cod fishery remains closed todirected fishing, as it has been since thefall of 1993. Catches have been taken asby-catch in other groundfish fisheries andsince 1996 in the Sentinel Programcommercial index. The 2002 fishing yearlandings, to October 7th, are 71t. Detailedhistorical information on the cod fishery isavailable in Mohn et al. (1998).
Resource Status
Information on the annual spatialdistribution and size composition from theJuly research vessel surveys is containedin Branton and Black (2002).
Maritimes Region 4VsW Cod
5
The abundance indicators from the mostrecent surveys all remain low with respectto their series. In particular, the large1997 estimate from the March surveystands out as an anomaly, notrepresentative of abundance. From 1999to 2002, the March and July surveyresults for each year are virtuallyindistinguishable. The Sentinel surveyhas declined steadily from 1998 to 2001(the most recent available data).
Survey indices in 4VsW cod (Ages 3+)
0
10
20
30
40
50
60
70
80
90
100
1970 1980 1990 2000
Num
bers
per
set
SentinelJuly RVMarch RV
168
Outlook
The three survey series all indicatecontinuing low and declining abundanceand have not indicated any majorrecruitment events in recent years. Untilrecruitment of several large year-classesis seen, there does not appear to be anybasis to expect stock growth.
The outlook from the last Stock StatusReport for this stock, based onassessment of the stock (DFO 1998,Mohn et al. 1998) included the following:
“The short-term prospects for thisfishery remain dismal. Theproductivity of the stock is verylow, there are several factorscausing increased mortality overallas well as seal predation on theyounger age groups. Thespawning stock biomass, while notdeclining, has not rebuilt since theclosure of the fishery.”
The new information available since thennow suggests that the spawning stockbiomass has been declining since 1998.
For More Information
Contact:
L. Paul FanningMarine Fish DivisionBedford Institute of OceanographyP.O. Box 1006, DartmouthNova Scotia, B2Y 4A2
Mohn R.K., L.P. Fanning, and W.J.MacEachern. 1998. Assessment of4VsW cod in 1997 incorporatingadditional sources of mortality. DFO.Atlantic Fisheries ResearchDocument 98/78.
Maritimes Region 4VWX+5Zc Pollock
7
Pollock in Divs. 4VWXand 5Zc
Background
Pollock (Pollachius virens) in the westernAtlantic range from southern Labrador to aboutCape Hatteras. The main fishableconcentrations occur in the Georges Bank, Gulfof Maine, and Scotian Shelf areas.
Young pollock are closely associated withnearshore habitats, recruiting to the offshorepopulations at around age 2. Based onobservations by fishermen and acoustic studies,pollock spend the least time on the bottom of allthe cod-like fish. Pollock show strong schoolingbehaviour. Food of adult pollock includeeuphausiids and fish such as herring, sandlance and silver hake.
Pollock are mature at ages 3 to 5 depending onthe area. Pollock also show marked differencesin growth rate by area, with fish in the Bay ofFundy area growing faster than those on theeastern Scotian Shelf.
The management unit includes the Canadianportion of Georges Bank and the Gulf of Maine,and the Scotian Shelf. A variety of fishing gearis used to fish pollock, primarily otter trawls andgillnets, but also includes handlines andlonglines. The otter trawl and gillnet fisheries areoften directed. Pollock can also be taken as by-catch in cod and haddock fisheries and in thesmall-mesh silver hake and redfish fisheries.
The most recent full assessment of thisstock was conducted in fall 1999(Neilson et al. 1999, DFO 1999).Annual updates have been conductedsince, the most recent being DFO(2001). More recent information from thefishery, commercial port samples, theresearch vessel and ITQ surveys ispresented in this update.
The FisheryLandings (000s t)Year 1980-
89Avg.
1990-97
Avg.
1998 19991 20002 2001 2002
TACTOTAL
- 40.5
27.6 23.8
20.0 14.4
13.4 8.9
10.0 5.5
10.0 6.2
10.0
1. Fishing year, landings and TAC refer to the 15-monthperiod from January 1, 1999 to March 31, 2000.
2. Commencing in 2000, fishing year, landings and TACrefers to the period April 1st of the current year to March31st of the following year.
0
10
20
30
40
50
60
1974 1977 1980 1983 1986 1989 1992 1995 1998 2001
ForeignCanadaTAC
Landings
TAC
Landings and TACs ('000s t)
Landings for the fishing year April 1,2001, to March 31, 2002, were 6203t.Landings in the current fishing year are4499t (includes those landings fromApril 1st through Aug. 22nd).
The pollock fishery continues to undergosignificant changes in both area fishedand in dominant gear type. The western(4X5Zc) half of the management unitusually contributes the largestproportion to total landings. The eastern(4VW) contribution has been following adeclining trend, and was 6% in 2001.Within 4X5Zc, the proportion of landingsfrom the western half (Unit Areas4Xpqrs) has increased from 29% in1991 to 55% in 2000 and 2001. Thechanges in the distribution of the fisherywere thought to reflect both thepopulation dynamics of the stock andfishery management measures. Duringperiods of lower landings (early 1970sand the present period), the contributionfrom the east is lower, suggesting
Maritimes Region 4VWX+5Zc Pollock
8
greater reductions in abundance. In thepresent period, the east is closed tocod-directed fishing, which furtherreduces pollock landings from that area.
Proportional Landings Within Management Unit Components
The contribution of larger trawlers to totallandings (Tonnage Class (TC) 4+), oncethe dominant gear type in the fishery, hasbeen steadily declining since 1981 andaccounted for 11% of total removals in2001. In contrast, the contributions of TC1-3 trawlers and fixed gear vessels(gillnet, longline) have been increasingover the same period and now accountfor 50 and 39% of the total landings,respectively.
The landings in the small (<65’) mobilegear fishery in 2001 and 2002 typicallyconsisted of ages 3-6, and agescomprising most of the gillnet fisherylandings are 4-7. The 1997 year-classwas identified as noteworthy at age 4 inthe 2001 SSR, and continues tocomprise a larger than average share ofthe catch at age 5. The 1998 year-classcontribution is slightly above average.Ages 8 and 9 comprise a smallerproportion of the gillnet landings in 2001and 2002 compared with the averagefrom 1990 to 1999.
���
������������
���������������������������
���������������������������
���������������
������ �� ��� ��� ��� ���
0
5
10
15
20
25
30
35
40
45
1 2 3 4 5 6 7 8 9 10 11 12
<65' Mobile20022001
Percent Catch at Age for Major Gear Types in 4X5Zc
10 Year Average
��� ���
������������
������������������������
���������������������������
���������������
������ ��� ��� ��� ���
0
5
10
15
20
25
30
35
40
45
1 2 3 4 5 6 7 8 9 10 11 12
Gillnets
Industry Perspective
During industry consultations in 2001,fishermen reported a varied experiencewith the fishery depending on what gearsector they belonged to. In 2002, moreuniformly positive reports were receivedfrom mobile gear fishermen. Onerepresentative of the large mobile gearoperators noted a slightly better fisherythan in 2001, and commented on animproved market for pollock. Operatorsof small mobile gear report havingexperienced a strong fishery in 2002,with some groups running out of quota.All representatives of the mobile gearfishery noted a good range of sizes inthe catch.
Reports from fixed gear fishermen weremore mixed. Gillnet fishermen reportedan average (Georges Bank) to poor(Bay of Fundy) fishery in 2002,compared with recent years. Gillnet
Maritimes Region 4VWX+5Zc Pollock
9
fishermen noted that by-catches of whitehake have negatively affected thepollock fishery. Longline fishermenreport similar experience with the fisheryin 2002 compared with 2001. Handlinefishermen generally reported poorpollock fishing compared with 2001.Most fixed gear fishermen reported thatthe size range in the fishery wasbroader than in recent years.
Resource Status
The indicator of abundance used in thisassessment is a standardized catchrate series that uses data from directedpollock trips of TC 1-3 otter trawlersoperating in 4X5Zc. The standardizedcatch rate series accounts for differencesin catch rate by vessel tonnage class,mesh type, unit area, month and year.
The catch rate series peaked in 1984 asthe strong 1979 year-class became fullyrecruited, and declined thereafter.Landings during that period were at theirhighest level historically. After a slightincrease from 1993 to 1995, the catchrate series decreased and remained at alow level from 1999 to 2001. Catch ratesin 2002 (as of Aug. 31) increasedmarkedly from 2001.
When the catch rate series is examinedon an age by age basis, the 1997 year-class is confirmed as being aboveaverage. The 1998 year-class (age 4 in
2002) is also above the recent average.However, the abundance (numbers) ofsome year-classes does not decline inthe expected fashion from 2001 to 2002,indicating that the large increase incatch rates from 2001 to 2002 isreflecting not only increased abundance,but also changes in availability.
1980
1985
1990
1995
2000
2 3 4 5 6 7 8 9Age
1997 Year-Class
Age-Specific Catch Rates (area of circ les isproportional to the catch rate)
Information on the annual spatialdistribution and size composition from theJuly research vessel surveys isprovided in Branton and Black (2002).Such data are not currently used as anindex of abundance in this assessment,because there is considerableunexplained interannual variation ofmany year-classes, which is inconsistentwith our knowledge of fisheries dynamics.However, the research surveyinformation on size structure indicatesfewer larger (>70 cm) fish in the surveyssince 1990, for both the eastern (4VW)and western (4X) halves. The absenceof larger fish is probably attributable torelatively high exploitation rates duringthe early 1990s (Neilson et al. 1999).
Recent surveys (1998 to 2000) havecaught more small pollock (<26cm) in 4Xthan in previous years. This wasparticularly noteworthy in 2000. Thosefish are one year old (1999 year-class).The 1999 year-class was also apparentin the 2001 and 2002 as ages 2 and 3,respectively.
Maritimes Region 4VWX+5Zc Pollock
10
The 2001 survey in 4VW also caughtmany more small (<26cm) pollock than inprevious years. In contrast to the 2000survey, where most of the fish <26cmwere found widely distributed in the Bayof Fundy, the small fish were found onthe Eastern Scotian Shelf in 2001, mainlyin a single large set. Small fish wererelatively abundant in the 2002 survey,but again were caught at only twostations.
Proportion of Pollock in Length Classes from RV Surveys
4VW
A joint industry/DFO Science surveyconducted by the ITQ fleet in 4X alsoindicated fewer fish >70 cm in 1999 to2001 compared with 1995 to 1998. In2000, large numbers of 20-25 cm (age 1,1999 year-class) fish were seencompared with previous years, andappeared in 2001 as 30-35 cm fish.However, that mode did not track throughto the 2002 survey.
Outlook
The Outlook from the 1999 Stock StatusReport noted:
“In summary, the pollock resourceremains depleted,….biomass isless than average, recentrecruitment has been poor, thereis an absence of older fish in thepopulation, and there are spatialchanges in the resource and in thefishery distributions that areworrisome. Caution in establishingharvest levels is required.”
In the 2000 review, it was noted thatwhile there were preliminary indicationsof improved recruitment from the fishery,catch rates remained comparatively low,large fish were rare in the catch and thesurveys, and the fishery remainedspatially constricted. The 2001 reviewindicated that the 1997 year-class wasmoderately strong and was recruiting tothe fishery. The 1999 year-class wasalso thought to be stronger than recentyear-classes. However, catch rates andthe abundance of larger fish remainedlow.
The current review confirms that the1997 year-class is stronger than therecent average and that there arepreliminary indications that the 1998 and1999 year-classes may also be abovethe recent average. However, thefishery remains spatially constricted,and the abundance of large fish remainslow. The rapid increase in catch ratesfrom 2001 to 2002 is probably due, inpart, to increased availability.
Catches up to the level of the 2002 TACwill likely permit rebuilding of theresource, and should result in areduction in exploitation rate.
Maritimes Region 4VWX+5Zc Pollock
11
For More Information
Contact:
John NeilsonSt. Andrews Biological StationSt. Andrews, New BrunswickE5B 2L9
Branton, R., and G. Black. 2002. 2002summer groundfish survey updatefor selected Scotia-Fundygroundfish stocks. DFO CanadianScience Advisory SecretariatResearch Document 2002/089.
DFO, 2001. Updates on selected ScotianShelf Groundfish Stocks in 2001.DFO Sci. Stock Status Report A3-35(2001).
DFO, 1999. Pollock in Div. 4VWX and SA5. DFO Sci. Stock Status Report A3-13(1999).
Neilson, J., P. Perley, and C. Nelson.1999. The 1999 assessment ofpollock (Pollachius virens) in NAFODivisions 4VWX and Subdivision5Zc. DFO Canadian StockAssessment Secretariat ResearchDocument 99/160.
Maritimes Region 4VWX Silver Hake
12
Silver Hake on the ScotianShelf (Div. 4VWX)
Background
Silver hake (Merluccius bilinearis) is a bottomdwelling member of the gadoid family, foundfrom Cape Hatteras to the Grand Banks and theGulf of St. Lawrence. A major concentration ofsilver hake occurs on the Scotian Shelf.
Scotian Shelf silver hake are generally foundbetween 7 and 10o C, in deeper water on theshelf edge and in the Emerald and LaHavebasins. Seasonal movements occur during thesummer, as silver hake move into shallow wateron Sable and Western banks to spawn. ScotianShelf silver hake feed primarily on invertebrates,with krill the predominant prey item. Older fishare piscivorous and exhibit a high degree ofcannibalism.
Silver hake exhibit relatively rapid growth withfemales growing faster than males. Maximumage is 12 years. Maturity is relatively early, witha majority of males maturing at age 2, andfemales at 3.
Historically, silver hake had been harvested onthe Scotian Shelf by foreign nations. Prior to1977, the fishery was unrestricted in terms ofarea and mesh size. From 1977 onwards,fishing for this species was limited to slopewaters on the seaward side of the Small MeshGear Line (SMGL), with a minimum mesh size of60mm diamond. In the 1990s, foreignallocations were phased out by 1998. Starting inthe mid-1990s, A Canadian fleet has harvestedsilver hake in Emerald and LaHave basins. Theproportion of the total catch by this fleet hasincreased over time, and since 1997, accountsfor the majority of the landings. In 2001, thedistribution of effort by this fleet expanded, withmany vessels fishing on the slope area as wellas in the basins. Given silver hake is harvestedwith small mesh gear, separator grates havebeen mandatory to control by-catch since 1993.
The most recent assessment of thisstock was conducted in fall 1999 (DFO1999). Annual updates have beenconducted since then, the most recentbeing DFO (2001). More recent landingsdata and information from the 2001 and2002 4VWX summer research vesselsurvey are presented in this update.
1. Fishing year, landings and TAC refer to the 15-monthperiod from January 1, 1999 to March 31, 2000.
2. Commencing in 2000, fishing year, landings and TAC referto the period from April 1st of the current year to March 31st
of the following year.3. Average TAC for 1974-79 period.
Landings for the 2002 fishing year (toOctober 7th) are 6700t, for which theslope portion is 4600t.
Landings, tonnes ('000)
020406080
100120140160
1979 1983 1987 1991 1995 1999
Basin
Slope
TAC
Resource Status
Information on the annual spatialdistribution and size composition fromthe July research vessel surveys iscontained in Branton and Black (2002).
Abundance and biomass from the DFOsummer research vessel (RV) surveyincreased slightly from 1998 to 2001,but dropped sharply in 2002, and are
Maritimes Region 4VWX Silver Hake
13
now at the lowest levels seen since1980.
Silver Hake - Biomass and Abundance (RV)
0
20
40
60
80
100
120
1970 1975 1980 1985 1990 1995 2000
Bio
mas
s
0
100
200
300
400
500
600
700
Abun
danc
e
biomassabundance
The RV age 1 recruitment indicatorshows that the 2000 and 2001 year-classes are below average. The fisherywill be dependent on these year-classesin 2002-03.
Total mortality over ages 2-4 from thesummer survey shows an increasingtrend since 1995. Total mortality forages important to the fishery is abovethat expected with F0.1 = 0.7 (assumingnatural mortality = 0.4), suggestingeither exploitation is relatively high(despite moderate catches) or thatnatural mortality has increased.
Total Mortality (ages 2-4)
0
0.5
1
1.5
2
2.5
1986 1988 1990 1992 1994 1996 1998 2000
There are long-term declining trends inbiological indicators. Condition (weightat 25cm), shows a general decline from1975 to 1993. An increase was seen in1995, but condition has declinedsubsequently to a low level relative tothe long-term average.
Condition Index
90
95
100
105
110
115
120
125
130
1970 1975 1980 1985 1990 1995 2000
Length-at-age has also shown adecline, from high levels in the early1970s to a low in 1995. Length-at-ageincreased from 1995 to 1998, butdeclined subsequently and remains justbelow the long-term mean.
Length at 50% maturity was highest inthe 1970’s but declined subsequently.Since 1993, it has remained stable at alower level.
Maritimes Region 4VWX Silver Hake
14
Length (cm) at 50% Maturity
20
21
22
23
24
25
26
27
28
29
1970 1975 1980 1985 1990 1995 2000
A measure of resource concentrationis the proportion of the historical stockarea encompassing 75% of the annuallyestimated survey biomass. For silverhake this index has been stable at ahigh level since 1994, indicating that theresource is widely distributed.
The proportion of annual survey setswhere the species occurs (non-zerosets) is a measure of the area occupiedby the species. This indicator has beenstable at a high level since 1994,indicating that the resource is widelydistributed.
The outlook from the last fullassessment for this resource indicatedthat catches should not be allowed toincrease from 1997-99 levels.
Survey biomass remains very low andtotal mortality is high. The extremevalues of these important indicatorscause substantial concern. In addition,condition, length-at-age, and size atmaturity are below long-term averages.
Recruitment prospects are poor, withthe both the 2000 and 2001 year-classes weak.
Resource concentration and distributionthrough the geographical range exhibitpositive trends.
The information added in the currentupdate indicates that the resource
Maritimes Region 4VWX Silver Hake
15
status continues to be poor and may beworsening.
For More Information
Contact:
Mark ShowellMarine Fish DivisionBedford Institute of OceanographyP.O. Box 1006, DartmouthNova Scotia, B2Y 4A2
Branton, R., and G. Black. 2002. 2002summer groundfish survey update forselected Scotia-Fundy groundfishstocks. DFO Canadian ScienceAdvisory Secretariat ResearchDocument 2002/089.
DFO, 2001. Updates on selected ScotianShelf stocks in 2001. DFO Sci. StockStatus Report A3-35(2001).
Showell, M.A., and L.P. Fanning. 1999.Assessment of the Scotian Shelfsilver hake population in 1998. DFO.Canadian Stock AssessmentSecretariat Research Document99/148.
Maritimes Region Unit 3 Redfish
16
Unit 3 Redfish
Background
Redfish, also known as ocean perch, occur onboth sides of the Atlantic Ocean. They arenormally found along the slopes of fishing banksand deep channels usually at 100 - 700 m inwater of 3 to 8 ° C. In the northwest Atlantic,redfish range from Baffin Island in the north toNew Jersey in the south. The predominantspecies on the Scotian Shelf are Sebastesfasciatus (Acadian redfish), occurring in the deepbasins and at the edge of the continental shelf,and S. mentella (beaked redfish) occurring in thedeeper waters off the continental shelf.Differences between these two species are notreadily apparent, therefore commercial andresearch catch are not routinely separated byspecies. Recent genetic research results confirmthat Unit 3 redfish are almost exclusively S.fasciatus and belong to a separate stock from S.fasciatus in Units 1 and 2. There is also anindication of a genetic separation betweenScotian Shelf and Gulf of Maine populations.While this genetic information provides importantinsights on stock structure, additional research isrequired, before its full implications areunderstood.
The Unit 3 management area (4WdehklX) forredfish was first implemented in the 1993Groundfish Management Plan with a quota of10,000 t. Redfish in this area were previouslymanaged as part of a larger 4VWX managementarea. Redfish in Unit 3 are primarily caught byotter trawlers using 90 mm mesh. Regulationslimit the by-catch in NAFO division 4X of othergroundfish species to 10 % by weight of redfishcaught and the by-catch in NAFO divisions 4VWto 2 % by weight each of cod and haddock.
The most recent assessment of thisstock was conducted in fall 1999 (DFO1999). Annual updates have beenconducted since, the most recent beingDFO (2002). The most recent
information for the fishery and summerresearch vessel survey is presented inthis update.
The Fishery
Landings (000s t)Year 1980-
89Avg.
1990-96
Avg.
1997 1998 19991 20002 20012 20022
TAC -- -- 10.0 10.0 9.4 9.0 9.0 9.0
Total 5.4 4.2 6.4 5.8 5.3 5.0 4.7
1 1999 TAC and landings refer to the 15 month period fromJanuary 1, 1999 to March 31, 2000.
2 Commencing in 2000, fishing year, landings and TACrefer to the period April 1st of the current year to March31st of the following year.
Redfish landings gradually increasedfrom the late 1970s, peaking at almost7000t in 1986 followed by a decline toabout 2000t in 1991. Landings peakedagain in 1997 at about 6000t. Totallandings for the 12 month period April2001 to March 2002 was 4700t.Landings in 2002 (April 1st to September11th) are 2850t.
Landings and TAC (000s t)
0
2
4
6
8
10
12
1977 1981 1985 1989 1993 1997 2001
ForeignCanadianTAC
Since 1998, otter trawlers (<65ft), fishingalmost entirely in the Crowell and Jordanbasin portions of the Gulf of Maine,accounted for the largest portion ofreported landings in Unit 3.
Maritimes Region Unit 3 Redfish
17
Otter Trawler (<65') Landings by Fishing Location
land
ings
(000
s t)
1990 1992 1994 1996 1998 2000 2002
0
1
2
3
4
5
6Crowell & Jordan BasinsEmerald & LaHave BasinsRoseway Basin & Western RidgeScotia Shelf Slope
The increase in landings after 1992,resulting from an increase in fishingeffort by otter trawlers, reflecteddecreased fishing opportunities for morevaluable species, and not an increase inredfish abundance. The decrease incatches since 1996, resulted from adecrease in effort by these samevessels, reflecting decreased demand atthe processing plants for the smaller fishand not a decrease in redfishabundance.
The extent of area occupied by ottertrawlers directing for redfish (mainspecies caught) has expanded since1990 with some stabilization in the mostrecent years.
Fishing success, as measured by ottertrawler catch rates, in Crowell andJordan basins, has not changed muchthrough most of the 1990s. Thecontinued high catches from this areahave mainly resulted from the sustainedconcentration of fishing effort there.Success for small trawlers in Emeraldand LaHave basins, has fluctuated overtime as new fishing locations are foundand exploited. Fishing success in theRoseway Basin and Western Ridge for2002, although higher than in otherareas of Unit 3, were mainly the result oflimited catches of small fish in that area.
Otter Trawler Catch Rates by Fishing Location
t / d
ay
1990 1992 1994 1996 1998 2000 2002
0
2
4
6
8
10
12
14Crowell & Jordan BasinsEmerald & LaHave BasinsRoseway Basin & Western RidgeScotia Shelf Slope
Since 1996, 22cm has been used as theminimum size in ConservationHarvesting Plans. Percentages bynumber of redfish landings under thissize were:
Following an FRCC recommendation,the protection area for small redfishlocated north of Browns Bank (known asthe ‘Bowtie’) was redefined in early 1998.Landings from that general area (4Xo)were very low through all of 1998 andinto 2002 (less than 10% of totallandings).
In addition to limits on percentage by-catch, a number of areas have beenclosed to redfish fishing to avoid by-catches of other species. Pollock as apercent of the redfish catch accounts formost of the reported by-catch in Unit 3and has increased steadily since 1994.
The highest by-catch rates for pollockwere in Crowell and Jordan basins, butgenerally neither industry normanagement has traditionallyconsidered the situation there to be aproblem because most of this by-catchconsisted of legal sized fish, which wascounted towards the vessel quotas.
Maritimes Region Unit 3 Redfish
18
Reported Landings of By-catch Species
% o
f red
fish
1990 1992 1994 1996 1998 2000 2002
0
5
10
15 PollockCodWhite HakeHaddockOther
Observer data for 1998-2002 indicate amuch higher by-catch rate for pollockand spiny dogfish (legally discarded)than do reported landings but theobserver data are too limited to allowextrapolation to the fleet as a whole.
Industry Perspective
Interviews with otter trawler operatorsduring 2001-02 indicated concerns overthe large by-catch of pollock. Theycommented that a lot of the pollock by-catch is undersize, particularly in theCrowell and Jordan Basins andexpressed considerable interest in fishingnorth of 43°30′. Some are alsoconcerned that redfish are beingoverexploited and have commented onseeing more small redfish in theircatches.
Resource Status
Information on the annual spatialdistribution and size composition fromthe July DFO research vessel surveys(RV) is contained in Branton and Black(2002).
RV estimates of biomass (< 200fm) inthe management unit, although highlyvariable between years, show no trendover time. Redfish smaller thancommercial size do not contributegreatly to this biomass estimate, so
survey biomass can be taken as anindicator for the size classes fishedcommercially. However, survey biomassunderestimates the actual biomass onwhich the commercial fishery is based,as not all of the commercial sized fishare available to the survey gear, andsome are outside the survey area(deeper than 200 fm).
RV Kilograms per Tow
1985 1990 1995 2000
0
10
20
30
40
50
The joint DFO Science/Industry (ITQ)survey in Division 4X provides biomassestimates similar to the research vesselsurvey for that area, but the estimatesare less variable. The ITQ surveysindicate abundance in 2002 similar toprevious years.
With regards to recruitment, the RVsurvey shows considerably more smallfish (< 22cm) in the late 1990s,particularly in the area north and east ofBrowns Bank, but a decline morerecently.
RV Numbers per Tow by Size Class
1985 1990 1995 2000
0
50
100
150
200total< 22 cm
Maritimes Region Unit 3 Redfish
19
The U.S. research vessel surveys in theGulf of Maine, which surveys part of theCanadian fishing grounds, indicate thatthe biomass of redfish appears to haveincreased during the mid-1990s throughcombined effects of growth and survivalof fish from a period of relativelysuccessful reproduction in the early1990s (Clark 2000).
Historically, F0.1 for redfish stocks hasbeen estimated to be an exploitationrate of approximately 12% (DFO 2000).However it has not been possible toestimate this in absolute terms. Theratio of recent catches compared toDFO survey biomass estimates is usedas a proxy which indicates thatexploitation is low and probably doesnot exceed F0.1.
Outlook
The outlook from the last assessmentreport (DFO 1999) stated:
"DFO research vessel surveysindicate stability in thepopulation biomass within themanagement unit and improvedrecruitment particularly in andaround Roseway Basin andWestern Ridge. Thisrecruitment, although promising,has not yet resulted in adetectable increase in thepopulation biomass, butcombined with the lowexploitation rates which currentlyprevail, should result in fishingand stock conditions in 2000/01being very much the same as inrecent years.
There is no biological or fisherybasis to suggest a need forchange in the management ofthe resource at this time."
Population biomass estimates, althoughvariable, have not changed much andshould result in fishing and stockconditions in 2003-04 being much thesame as in recent years. However,there is evidence that the period ofimproved recruitment may be over,which would have consequences foryield in the medium term.
For Further Information
Contact:
Robert BrantonMarine Fish DivisionBedford Institute of Oceanography1 Challenger Drive, DartmouthNova Scotia, B2Y 4A2
Clark, S.H, (Ed.). 2000. Status of theFishery Resources off theNortheastern United States. NOAATechnical Memorandum NMFS-NE-115.
DFO, 2001. Updates on SelectedScotian Shelf Groundfish Stocks in2001. DFO Sci. Stock Status ReportA1-35(2001).
DFO, 1999. Status of Redfish Stocks inthe Northwest Atlantic: Redfish inUnits 1, 2 and 3, and in Division 3O,DFO. Sci. Stock Status Report A1-01(1999).
Maritimes Region 4VWX Witch Flounder
21
Witch Flounder on theScotian Shelf (Div. 4VWX)
Background
Witch flounder (Glyptocephalus cynoglossus)occur in the Northwest Atlantic from off southernLabrador to Cape Hatteras, usually at 50 - 300min water of 2 to 6ºC. but they have beenrecorded between 18 and 1570m and at -1 to11ºC. They occur most commonly in deep holesand channels and along the shelf slope onmuddy bottom. There is no evidence that witchundertake extensive migrations but there areseasonal changes in concentration associatedwith spawning. The spawning period isprotracted, and on the Scotian Shelf is thoughtto occur from May to October with a peak inJuly-August. The post-larval, pelagic phase isunusually long, lasting up to one year, and it isthought that the first few years of demersal lifeare spent in much deeper water than adults.Food consists of primarily of wormssupplemented by other benthic invertebratessuch as small crustaceans and bivalve molluscs.Witch is a long-lived, slow growing species; amaximum age of about 30 years and amaximum size of 78 cm (weight of about 5 kg)have been recorded.
Stock structure of witch flounder is not knownand Div. 4VWX is a management unit based onadministrative, rather than biologicalconsiderations. There is continuity in distributionof witch between Div. 4V and Div. 4RST andDiv. 3P that suggests some affinities amongthese populations. Similarly, concentrations ofwitch in western Div. 4X are continuous withthose in the rest of the Gulf of Maine.
The most recent assessment of thisstock was conducted in 1997 (DFO1997). Annual updates have beenconducted since, the most recent beingDFO (2001). More recent informationfrom the fishery and the summer
research vessel survey is presented inthis update.
The FisheryLandings (tonnes)
Year 1977-
79Avg.
1980-89
Avg.
1990-97
Avg.1998 1999
12000
2 2001 2002
Total 2264 2259 1217 766 775 561 609
1. Fishing year, landings and TAC refer to the 15-monthperiod from January 1, 1999 to March 31, 2000.
2. Commencing in 2000, fishing year, landings and TACrefer to the period April 1st of the current year to March31st of the following year.
The 2002 landings are 323t for theperiod April 1st to September 30th.Historical information on the witchflounder fishery is contained in McRueret al. (1997). Witch flounder is managedas part of the flatfish TAC for 4X and4VW.
Landings (000s t)
0
1
2
3
1975 1980 1985 1990 1995 2000
4X
4VW
Resource Status
Information on the annual spatialdistributions and size composition fromthe July research vessel surveys iscontained in Branton and Black (2002).
There were signs of improvedrecruitment (<20cm), to the stocks from1994-1999. More recent recruitmenthas been close to the long0termaverage.
Maritimes Region 4VWX Witch Flounder
22
Survey weight per tow increased from alow in 1995, but is still low relative to thelong-term. However, over the sameperiod the survey numbers-per-tow haveincreased and are above the long-termaverage.
Summer Survey Mean Numbers and Weights
0
5
10
15
1970 1975 1980 1985 1990 1995 2000
Num
bers
per
tow
0
3
6
9
Wei
ghts
per
tow
NumberWeight
Outlook
Biomass remains low. However, thestrong year-classes (<15cm) from 1994-99 have produced good signs ofimproved recruitment coming into thefishable population (>35cm) in the nearfuture.
Although the new information continuesto support a positive view of recovery,the short-term outlook for the stock fromthe 1997 assessment remainsunchanged, as does the conclusion that“…The proportion of flatfish landingsattributable to witch flounder should bemaintained close to the status quo”.
For More Information
Contact:
Jeff McRuerMarine Fish DivisionBedford Institute of OceanographyP.O. Box 1006, DartmouthNova Scotia, B2Y 4A2
Branton, R., and G. Black. 2002. 2002summer groundfish fish surveyupdate for selected Scotia-Fundygroundfish stocks. DFO CanadianScience Advisory SecretariatResearch Document 2002/089.
DFO, 2001. Updates on Selected ScotianShelf Groundfish Stocks in 2001.DFO Sci. Stock Status Report. A3-35(2001).
McRuer, J., R.G. Halliday, R.M. Branton,M.A. Showell, and R. Mohn. 1997.Status of witch flounder in Div. 4VWXin 1997. DFO Canadian StockAssessment Secretariat ResearchDocument 97/106.
4X American Plaice, YellowtailMaritimes Region Flounder, and Winter Flounder
24
American Plaice, YellowtailFlounder, and Winter
Flounder on the WesternScotian Shelf (Div. 4X)
Background
Flatfish are bottom dwelling fishes primarily associatedwith soft substrate (mud and sand bottom). They areunique among other fish in being asymmetrical, botheyes lying on one side of the highly flattened body.Early in life, they start swimming on one side, and theeye on the underside migrates to the upper side.Flatfishes lie on the bottom on the blind side. Principalfood items include crustaceans, molluscs, polychaeteworms and small fishes.
Prior to 1994, yellowtail flounder (Limanda ferruginea),witch flounder (Glyptocephalus cynoglossus) andAmerican plaice (Hippoglossoides platessoides) weremanaged as one stock complex (4VWX); winterflounder (Pseudopleuronectes americanus) wasexcluded from management considerations. In 1994,the management area was divided into an eastern(4VW) and western (4X) component, winter flounderwas included, and the overall Total Allowable Catch(TAC) partitioned between the two areas based oncatch history. The flounder fishery in 4X was placedunder the Individual Transferable Quotas (ITQ)program in August 1994.
Management of the four species together under oneTAC reflected the fact that it has been impossible toobtain reliable statistics on landings separated byspecies. The reported witch flounder landings aregenerally considered to be reliable, due to the higherprice paid for this species. But the unreliability of thecatch data for the other three species, coupled withthe reports from the fishing industry of serious mis-reporting of other species as flatfish prior to 1991eliminates the value of that information in determiningresource exploitation. Initiation of ITQ logs anddockside monitoring of landings has had limitedsuccess in separating catch to individual speciesbecause landings were not separated at weighout orwere misidentified by the weighmaster. It was decidedto assess witch flounder separately from the otherthree species in 1997, but it is still managed as part ofthe general flounder TAC.
The most recent assessment of thisstock was conducted in 1997 (DFO1997). Annual updates have beenconducted since 1999, the most recentbeing DFO (2001). More recentinformation from the fishery and thesummer research vessel survey ispresented in this update.
The FisheryLandings (000s t)
Year 1977-79 Avg.
1980-89 Avg.
1990-96 Avg.
1997 1998 19992 20003 2001 2002
TAC1
Total 3.2 4.3 4.53.02.2
2.01.7
2.32.0
2.02.0
2.02.0
2.0
1. The TAC and landings include witch flounder andunidentified flatfish.
2. Fishing year, landings and TAC refer to the 15-monthperiod from January 1, 1999 to March 31, 2000.
3. Commencing in 2000, fishing year, landings and TACrefer to the period April 1st of the current year to March31st of the following year.
Total flatfish landings in the 2001fishing year were 1997t. Landings offlatfish in 4X+5 for the 2002 fishing yearto September 5, 2002, are 1025t(including witch flounder, but excluding5Z yellowtail flounder).
Landings (000's t)
0
1
2
3
4
5
6
7
1977 1980 1983 1986 1989 1992 1995 1998 2001
TAC
Historical information on winter flounder,yellowtail flounder and American plaiceis contained in Stobo et al. (1997). Thebiggest problem for managing flatfishstocks has been inability to segregatethe fisheries by species, andconsequently overall quotas wereapplied to combined fisheries. In 1999,the Fishing Log database was used tosubstitute species identifications where
4X American Plaice, YellowtailMaritimes Region Flounder, and Winter Flounder
25
unspecified flounder was entered in theCommercial Landings database (Fowlerand Stobo, 1999). These revizedlandings would indicate a much larger,but declining, fishery for American plaicein 4X/5 than previously thought.
Resource Status
Information on the annual spatialdistributions and size composition fromthe July research vessel survey iscontained in Branton and Black (2002).
Summer research vessel (RV) surveyinformation indicates that the abundanceof winter flounder has varied considerablyin recent years, but is currently wellabove average. A large pulse of youngAmerican plaice in 1999 was notsustained in the population, abundancedropping to a very low level by 2001. In2002, plaice abundance increased to anear-average level, although weight pertow remains very low. Yellowtail flounderabundance dropped from a record high in2001, but the 2002 estimate is still aboveaverage for the time series.
W inter Flounder
0
2
4
6
8
10
12
1970 1975 1980 1985 1990 1995 2000
Num
ber p
er to
w
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Wei
ght (
kg) p
er to
w
Number per towWeight (kg) per tow
American Plaice
0
2
4
6
8
10
12
14
16
1970 1975 1980 1985 1990 1995 2000
Num
ber p
er to
w
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Wei
ght (
kg) p
er to
w
Number per towWeight (kg) per tow
Yellowtail Flounder
0
1
2
3
4
5
6
7
1970 1975 1980 1985 1990 1995 2000
Num
ber p
er to
w
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Wei
ght (
kg) p
er to
w
Number per towWeight (kg) per tow
Outlook
The lack of adequate informationregarding species identification oflandings covered by the generic 4Xflatfish TAC is a major constraint toconducting assessments of the threeseparate stocks within the singlemanagement unit. Current informationindicates a very mixed set of stock statusscenarios -- a worsening situation forAmerican plaice, an improving situationfor yellowtail flounder, and relativestability in stock status of winter flounder.
4X American Plaice, YellowtailMaritimes Region Flounder, and Winter Flounder
26
For More Information
Contact:
Mark FowlerMarine Fish DivisionBedford Institute of OceanographyP.O. Box 1006, DartmouthNova Scotia, B2Y 4A2
Branton, R., and G. Black. 2002. 2002summer groundfish fish surveyupdate for selected Scotia-Fundygroundfish stocks. DFO CanadianScience Advisory SecretariatResearch Document 2002/089.
DFO, 2001. Updates on selected ScotianShelf groundfish stocks in 2001.DFO Sci. Stock Status Report A3-35(2001).
DFO, 1997. Southwest Nova WinterFlounder, American Plaice andYellowtail Flounder. DFO Sci. StockStatus Report A3-21(1997).
Fowler, G.M., and W.T. Stobo. 1999.Reconciliation of processed catchstatistics with log data for 1992-97flatfish in 4VWX/5Y. DFO CanadianStock Assessment SecretariatResearch Document 99/149.
Stobo, W.T., G.M. Fowler, and S.J.Smith. 1997. Status of 4X winterflounder, yellowtail flounder, andAmerican plaice. DFO CanadianStock Assessment SecretariatResearch Document 97/105.
Maritimes Region 4VWX Cusk
27
Cusk on the Scotian Shelf(Div. 4VWX)
Background
Cusk (Brosme brosme) is a solitary, slowswimming species, found primarily on thesouthwestern Scotian Shelf and Slope and in theFundian Channel, that seldom moves from bankto bank. Based on July research surveys, cuskoccur in temperatures ranging from 3 to 11�Cwith most being caught in the 6-10 0 C range, atdepths of 75-150 m. They also prefer a rockybottom, or gravel and occasional mud butseldom sand.
Spawning on the Scotian Shelf is believed tooccur from May to August, peaking in June. Thebuoyant eggs are 1.3-1.5 mm in diameter with apinkish oil globule. The pelagic larvae are about4 mm when hatched, migrating to the bottomwhen they have grown to approximately 50 mmin length. Males appear to grow slightly fasterthan females, (reaching 45 cm at five years ofage) and appear to mature more rapidly.
The diet of cusk on the Scotian Shelf isunknown, as their stomachs evert when they arebrought to the surface. In European waters, cuskfeed primarily on crabs and molluscs, along withthe occasional starfish. Observations on thisside of the Atlantic reveal cusk feeding on crabsand the occasional mollusc off the coast ofMaine. The only known predation record was bya hooded seal off Greenland. There is no recordof cusk occurring in seal stomachs on theScotian Shelf.
The most recent assessment of thisstock was conducted in 1998 (DFO1998). Annual updates have beenconducted since then, the most recentbeing DFO (2001). More recentinformation from the fishery and thesummer research vessel surveys ispresented in this update.
The FisheryLandings (tonnes)Year 1970-
79Avg.
1980-89
Avg.
1990-96
Avg.
1997 1998 19991 20002 2001
4VW4XTOTAL
46840014469
39528823277
40821652573
17414751649
18613041490
179879
1058
109717826
10110371138
1. Fishing year and landings refer to the 15-month periodfrom January 1, 1999 to March 31, 2000.
2. Commencing in 2000, fishing year and landings refers tothe period April 1st of the current year to March 31st of thefollowing year.
Cusk was placed under by-catchlimitations for the first time in 1999. A capof 1000t was placed on the combinedlandings of all fleets. The 2002 fishingyear landings, April 1st to September 11th,are 668t. The total landings for the 2002fishing year will likely be within the 1000tcap.
Cusk are primarily caught by longline(95%), with over 80% of the landingscoming from 4X. In 4X, landings havevaried from a maximum of 5,130t in 1973to a low of 717t in 2000. The generalpattern of landings is one of a gradualdecrease from the early 1970s to thepresent. Landings in Division 4W haverarely exceeded 500t, while landings inDivision 4V have been negligible.
0
2
4
6
8
1970 1975 1980 1985 1990 1995 2000
4VW 4X
Landings ('000t)
The most common (modal) size incommercial length frequency samples of
Maritimes Region 4VWX Cusk
28
cusk from the early 1970s and early1980s was between 64 to 67cm, similarto modal size in the research vesselsurvey over the same period. These areconsistent with modal sizes reported byOldham (1972) from LaHave Bank in themid 1960s. The size composition fromcommercial samples since 1988 hasshown no consistent pattern with modesranging from 52-61 cm.
Resource Status
Information on the annual spatialdistribution and size composition fromthe July research vessel surveys iscontained in Branton and Black (2002).
Research vessel (RV) survey indicatorsin 4W show a gradual decline in bothnumbers and weight-per-tow since thesurveys started in 1970. In 4X (thecentre of the historical distribution), theseindicators show a gradual decline in bothnumbers and weight-per-tow since the1970s with a collapse during 1991-93.
0.0
0.5
1.0
1.5
2.0
2.5
1970 1975 1980 1985 1990 1995 2000
4V
4W
4X
4VWX
Summer Survey No. per Tow
Summer Survey (kg) perT
0.0
1.0
2.0
3.0
4.0
5.0
6.0
1970 1975 1980 1985 1990 1995 2000
4V4W4X4VW X
Mean weight per individual from the RVsurvey has declined since 1989.
Summer Survey Weight per Individual
1.0
1.5
2.0
2.5
3.0
3.5
4.0
1970 1975 1980 1985 1990 1995 2000
4X4VWX
A comparison of the geographicdistribution from summer RV surveysindicates a significant contraction of cuskdistribution in recent years.
Maritimes Region 4VWX Cusk
29
The proportion of annual survey setswhere the species occurs (non-zerosets) is a measure of the area occupiedwithin its historical geographic range.For cusk, this index has shown a steadydecline since the late 1980s, indicatingconcentration of the resource.
Proportion of Non-zero Sets
0
0.05
0.1
0.15
0.2
0.25
1970 1975 1980 1985 1990 1995 2000
Outlook
The outlook from the 1998 assessment(DFO 1998) for this stock included thefollowing:
“Given the apparent collapse ofthe cusk population since 1992,immediate and substantialrestrictions on cusk landings arerequired. Elimination of thedirected fishery is necessary.Rebuilding of the stock willprobably require a combination ofboth traditional and innovativemeasures. A restrictive by-catchwould aid in rebuilding efforts, butmay be difficult to implementwithout discarding.”
Despite the recent introduction of catchcontrols, this is a stock which shows nosigns of improvement. While the factorsaffecting the population abundance ofcusk are not well understood, it ispossible that the 1000t cap placed on thisstock is not providing adequaterestrictions on catches to allow for thestock to rebuild and more restrictivemeasures may be required.
For More Information
Contact:
Peter ComeauMarine Fish DivisionBedford Institute of OceanographyP.O. Box 1006, DartmouthNova Scotia, B2Y 4A2
