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Has man learned to manage cod? (1005.Kb)

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Has man learned to manage cod?

Gudrun Marteinsdottir

University of Iceland

(2)

North Atlantic cod stocks

Sundby, 2000

RDIST=Roger genetic distance (Pogson, 1995) See also:

Bentzen et al 1996 Hutchinsons et al., 2001 Arnason, 2004

Galvin et al., 1995

Fst=0.008

Ruzzante et al. 1998 Beacham et al., 2002

R-DIST=0.09

(3)

North East Atlantic cod stocks

Nielsen et al. 2003

Pairwise genetic differentiation (Fst) between

North Sea and the other samples

NAC – coastal cod

MØller, 1966; Fevolden and Pogson, 1997 – Sarvas 2005; Mork and Gjæver,1999, Jørstad &

Nævdal 1989

Faroe Island –

Difference between Bank and Plateau. Sick, 1965; Nielsen et al. In prep.

North Sea –

Differences among Bergen Bank, Moray Firth, Flamborough Headd, S. Bight Hutchinson et al., 2001

Baltic –

No differences. Sick, 1965; Nielsen et al., 2003

Iceland N vs. S –

Pampoulie et al. 2006

(4)

Total Catch of cod in the North Atlantic

0 500000 1000000 1500000 2000000 2500000 3000000 3500000 4000000

1968 1973 1978 1983 1988 1993 1998 2003

(5)

North Atlantic cod stocks

Landings

0 200000 400000 600000 800000 1000000 1200000 1400000 1600000

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

NAC NS

ICE Green

Celtic Irish

W-Scotl Faroe

WBALT KAT

EBALT Northern cod

Grand Bank N-st.Law S.st.Law St. Pierre George Bank Flemmish Gufl Main Scot. Shelf

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Assessement Working Group Reports

Brattey, J., N. G. Cadigan, B. P. Healey, G. R. Lilly, E. F. Murphy, D. E. Stansbury and J.-C. Mahé.

2003. An assessment of the cod (Gadus morhua) stock in NAFO subdiv. 3Ps in October 2003.

CSAS Research Document 2003/092.

Cervino, S. and A. Vázquez. 2004. A survey based assessemnt of cod in division 3M. NAFO SCR Doc. 04/53

Chouinard, G. A., and D. P. Swain, L. Currie, G. Poirier, A. Rondeau, H. Benoit, T. Hurlbut, D. Daigle.

2003. Assessment of the cod in the southern Gulf of St. Lawrence, February 2003. CSAS Research Document 2003/015.

Fanning, L.P., R. K. Mohn and W. J. MacEachern. 2003. Assessment of 4VsW cod to 2002. CSAS Research Document 2003/027

Fréchet, A., J. Gauthier, P. Schwab, H. Bourdages, D. Chabot, F. Collier, F. Grégoire, Y. lambert, G.

Moreault, L. Pageau and J. Spingle. 2003. The status of cod in the Northern Gulf of St. Lawrence (3Pn, 4RS) in 2002. CSAS Research document 2003/065.

ICES2004a. Report of the Arctic fishery working group. ICES CM 2004/ACFM:28

ICES 2004b. Report of the Baltic Fisheries Assessment Working Group. ICES CM 2004/ACFM:22.

ICES 2004c. Report on the assessment of demersal stocks in the North Sea and Skagerakk. ICES CM 2004/ACFM:07

ICES 2004d. Report of the working group on the Assessment of the Southern Shelf Demersal Stocks.

ICES CM2004/ACFM:03

ICES 2005. Report of the working group on the assessment of Northern shelf demarsal stocks (WGNSDS). ICES CM 2005/ACFM:01

ICES 2004e. Report of the North Western working group . ICES CM 2004/ACFM:25

ICES 2001. Report of the Baltic Fisheries Assessment Working Group. ICES CM 2001/ACFM:18.

ICES 2002. Report of the study group on incorporation of process information into stock recruitment models. ICES CM 2002/C:01.

Lilly, G.R., Shelton, P.A., Brattey, J., Cadigan, N., Murphy, E.F., Stansbury, D.E., Davis, M.B., and Morgan, M.J. 1998. An assessment of the cod stock in NAFO Divisions 2J+3KL. DFO Can. Stock Assess. Sec. Res. Doc. 98/15.

Lilly, G.R., Murphy, E.F., Healey, B.P., Maddock Parsons, D., and Stead, R. 2004. An update of the status of the cod (Gadus morhua) stock in NAFO Divisions 2J+3KL in March 2004. DFO Can. Sci.

Adv. Sec. Res. Doc. 2004/023.

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0 1000 2000 3000 4000 5000

NAC W-BALT

E-B ALT

KAT NS CE IR WSCOT

FAROE ICE

GREEN NORTH

FLEM ISH

GRAND PIERRE

SLAW NLAW

NSCOT G MAIN

GEORGE B

Thousand tonnes

North Atlantic cod stocks

max stock size

(8)

0 1000 2000 3000 4000

NAC W-BALT

E-B ALT

KAT NS CE IR WSCOT

FAROE ICE

GREEN NORTH

FLEM ISH

GRAND PIERRE

SLAW NLAW

NSCOT G MAIN

GEORGE B

Thousand tonnes

North Atlantic cod stocks

Max spawning stock biomass

(9)

North Atlantic cod stocks

Historical changes in stock size

0 500 1000 1500 2000 2500 3000 3500 4000 4500

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

NAC ICE

Green Northern

(10)

North Atlantic cod stocks

Historical changes in stock size

0 200000 400000 600000 800000 1000000 1200000 1400000

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

NS E-BALT

N-St.LAW S-St.LAW

(11)

North Atlantic cod stocks

Historical changes in fishing mortality

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

NAC ICE

E-Baltic North Sea

(12)

-100 -50 0 50 100

NAC WB EB KAT NS CE IR WS F ICE G NO FL GR PI SL NL NS GM GB

%

North Atlantic cod – rate of change (%)

-100 -50 0 50 100

%

-100 -50 0 50 100

NAC WB EB KAT NS CE IR WS F ICE G NO FL GR Pi SL NL NS GM GB

%

Landings

SSB

Recruitment

rate of change = difference between first 5 – last 5 year

(13)

NAC 1946

0 20 40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

NAC 2003

0 20 40 60

1 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

ICE 1955

0 20 40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

ICE 2004

0 20 40

1 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

North Atlantic cod stocks Spawning stock age structures

%

(14)

North Atlantic cod stocks

Proportion 10+ or 6+

0 5 10 15 20

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

%

NAC (10+) ICE (10+) North Sea (6+) Grand (10+) George Bank

Very low recruitment at

Grand Bank

(15)

-100 -75 -50 -25 0 25 50 75 100

%

North Atlantic cod – % rate of change

-100 -75 -50 -25 0 25 50 75 100

NAC WB EB KAT NS CE IR WS F ICE G NO FL GR Pi SL NL NS GM GB

%

Proportion old cod (6 or 10+)

Age Diversity (Shannon index)

(16)

Grand Bank 1959

0 20 40 60

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Grand Bank 2003

0 20 40 60

1 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

West Scotland 1978

0 20 40 60

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

West Scotland 2004

0 20 40 60

1 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

North Atlantic cod – Age structures

(17)

North Atlantic cod stocks

Proportion surviving to age at 50% maturity

0 0.1 0.2 0.3

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

%

NAC ICE

North Sea Northern

(18)

0 10 20 30 40 50

NAC W-BALT

E-B ALT

KAT NS CE IR WSCOT

FAROE ICE

GREEN NORTH

FLEM ISH

GRAND SLAW

NLAW NSCOT

G MAIN GEORGE B

Ye a rs s in ce d e ce n t re cru itm e n t

North Atlantic cod stocks

“Recruitment Health index”

decent recruitment > 3rd quartile

2003 2003 1995 1997

1981 1985

1995 1998

1991 1988

1999

1984 1983 1967

1991 1968

1986

1982 1983

(19)

North Atlantic cod stocks

Expected catch – Recorded catch

-50 -40 -30 -20 -10 0 10 20 30

1985 1990 1995 2000 2005

%

NAC ICE North Sea

Catch exceeded adviced TAC

Catch less than adviced

TAC

(20)

Status of the North Atlantic cod stocks

Thank you !

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