Has man learned to manage cod?
Gudrun Marteinsdottir
University of Iceland
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
North East Atlantic cod stocks
Nielsen et al. 2003
Pairwise genetic differentiation (Fst) betweenNorth 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., 2001Baltic –
No differences. Sick, 1965; Nielsen et al., 2003Iceland N vs. S –
Pampoulie et al. 2006Total Catch of cod in the North Atlantic
0 500000 1000000 1500000 2000000 2500000 3000000 3500000 4000000
1968 1973 1978 1983 1988 1993 1998 2003
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
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.
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
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
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
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
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
-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
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
%
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
-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)
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
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
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
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