Distribution and Migration of cod,

the impact of climate

Geir OttersenInstitute of Marine Research, Bergen, Norway

and

Douglas P. SwainDepartment of Fisheries and Oceans,

Gulf Fisheries Centre, Moncton, N.B., Canada

IMR

Highlights from the Distribution and migration chapter of a book on ICES/GLOBEC Cod and Climate Change WG science: ”Cod in a changing climate – effects of physical variability on a

key predator in North Atlantic marine ecosystems”edited by K. Drinkwater and K. Brander

I will present examples from different stocks on

Habitat associations

Seasonal migrations

Geographic range and its variation

IMR

Sundby (2000)

Distribution of Atlantic cod and sea temperatures at 100m depth

Atlantic cod

Canada

Norway

Russia

Greenland

UK

Spain

Habitat associations

– Temperature preferences– Depth preferences– Ontogenetic variation– Interannual variation– Seasonal variation

IMR

Seasonal variations in temperature distribution of cod

Georges Bank, W and E Scotian Shelf, S. Gulf St. Lawrence

Seasonal variations in depth distribution of cod

Georges Bank, W and E Scotian Shelf, S. Gulf of St. Lawrence

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1988 1989 1990 1991 1992 1993 1994 1995

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bien

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3456

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Interannual and ontogenetic variability in temperature distribution of codMean ambient winter temperature Arcto-norwegian cod age 1-7

Seasonal variation in ambient temperature of Arcto-norwegian cod

K. Michalsen, IMR

Seasonal migrationsbetween spawning grounds, nursery areas

and adult feeding grounds

Seasonal migration patterns of two large, highly migratory northern stocks:

- Southern Gulf of St. Lawrence - Arcto-norwegian (Barents Sea)

IMR

Southern Gulf of St. Lawrence cod: Seasonal migrations and spawning grounds

Arcto-norwegian cod: Seasonal migrations and spawning grounds

IMR

Geographic range and its variation

- Interannual and ontogenetic changes in geographic range

- Density-dependent changes in geographic range

Spread of Cod at West Greenland

Late 1960 decline and retreat

1900 Cape Farewell & Fiskenes Bank

1917-18 Fredrikshaab

1919 Godhaab

1922 Sukkertoppen

1927-30 Christianshaab

1931-36 Umanak

Late 1930’s Upernavik

Modified from Keith Brander, ICES

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50

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Abundance (millions)

Density-dependent changes in geographic distribution for Southern Gulf of St. Lawrence cod

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1970 1975 1980 1985 1990 1995 2000

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Geographic distribution in September of 5-yr old Southern Gulf of St. Lawrence cod during periods of low abundance (1973-1975, 1993-1995), high abundance (1980-1982) and recent (2001).

Relative distribution and abundance of cod in NW Atlantic 1979-2002 derived from NEFSC Spring bottom trawl surveys.

Short animation

Yellow circles: Cod presentLarger circles: More cod+: Stations without cod

Thanks to Mike Fogarty for use of the maps

Example of change in geographic range

Thanks for your attention!

Geir Ottersen

IMR