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Climate change and fisheries Keith Brander ICES

What's this talk about?. Blowed if I know. Climate affects fisheries Climate affects biodiversityFisheries affect biodiversityFishing has a bigger effect on biodiversity than does climate changeOur time series of changes in fish populations mainly come from fisheries. Characteristics of marine

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Climate change and fisheries Keith Brander ICES

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    1. Climate change and fisheries Keith Brander ICES/GLOBEC Coordinator

    2. In a landmark paper published 10 years ago, Brodeur and Ware showed that zooplankton biomass in the Gulf of Alaska doubled between the 1950s and 1980s. The pattern of distribution also changed - in the 50s the majority of the biomass was in the middle of the Alaska Gyre. In the 1980s, the greatest part of the biomass was located at the periphery of the Gyre.In a landmark paper published 10 years ago, Brodeur and Ware showed that zooplankton biomass in the Gulf of Alaska doubled between the 1950s and 1980s. The pattern of distribution also changed - in the 50s the majority of the biomass was in the middle of the Alaska Gyre. In the 1980s, the greatest part of the biomass was located at the periphery of the Gyre.

    3. Climate affects fisheries Climate affects biodiversity Fisheries affect biodiversity Fishing has a bigger effect on biodiversity than does climate change Our time series of changes in fish populations mainly come from fisheries

    4. Characteristics of marine fish populations compared with terrestrial populations and freshwater fish Large population sizes Fewer boundaries to migration High fecundity Often have dispersive planktonic stage Undergo large population fluctuations Humans don�t live in the sea

    5. Effects of climate on fish and fisheries Look at periods prior to fishing Look for effects (e.g. stock increase) which are unlikely to be due to fishing

    6. Cod landings at Greenland Overfishing drove down the biomass and didn�t leave anything to build on.Overfishing drove down the biomass and didn�t leave anything to build on.

    7. Distribution shifted North by about 1000 km in 20 years and then retreated again. Cod have not recovered at Greenland, but it�s not clear that the temperature has risen very much there.Distribution shifted North by about 1000 km in 20 years and then retreated again. Cod have not recovered at Greenland, but it�s not clear that the temperature has risen very much there.

    9. top-sail dory first reached European waters in 1966at 38 oN and by 1994 had been caught at 55 oN. Depth range is 100-500m.top-sail dory first reached European waters in 1966at 38 oN and by 1994 had been caught at 55 oN. Depth range is 100-500m.

    10. Scottish records of red mullet and bass do not show any trend, but are not based on standard sampling. IYFS surveys carried out by RV Scotia in February Sea bass caught in western Norway (61.5 oN 5.1oE) on 4 November 2000 Swordfish (Xiphias gladius) and Sunfish (Mola mola) caught in Norway last year.Scottish records of red mullet and bass do not show any trend, but are not based on standard sampling. IYFS surveys carried out by RV Scotia in February Sea bass caught in western Norway (61.5 oN 5.1oE) on 4 November 2000 Swordfish (Xiphias gladius) and Sunfish (Mola mola) caught in Norway last year.

    12. Conclusions about climate and fisheries affects distribution (migration, growth, recruitment, mortality) change in (relative) abundance temperature is not the only factor

    14. What do we mean by loss of biodiversity? species extinction stock extinction which may or may not entail- loss of alleles loss of genotypes adverse change in genotype frequency change in (relative) abundance what about changes in distribution?

    16. there are probably very severe effects on some sensitive systems e.g. coral reefs and these will also affect fish most of our information is about changes in distribution and relative abundance should biodiversity be measured in a Eulerian or Lagrangian way?

    17. Fishing causes mortality and is usually selective.

    18. Effect of fishing on life expectancies

    25. Fishing causes mortality and is usually selective. Therefore it may cause: species extinction stock extinction which may or may not entail- loss of alleles loss of genotypes adverse change in genotype frequency change in (relative) abundance

    26. North Sea cod spawning stock biomass

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