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Seals, dolphins & salmon in the Moray Firth

Seals, dolphins & salmon in the Moray Firth. Paul Thompson University of Aberdeen. Food. Climate variation/change. Food. Seals. Dolphins. Net & Rod Catches. Parr. Smolts. Eggs. Breeding Stock Size. Food. Tourism. Climate variation/change. Killer whales. Afforestation. Red deer.

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Seals, dolphins & salmon in the Moray Firth

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  1. Seals, dolphins & salmon in the Moray Firth Paul Thompson University of Aberdeen

  2. . Food Climate variation/change Food Seals Dolphins Net & Rod Catches Parr Smolts Eggs Breeding Stock Size

  3. . Food Tourism Climate variation/change Killer whales Afforestation Red deer Cormorants Industrial Pollution Porpoises Over-grazing Food Cod Goosanders Seals Dolphins Parr Acid rain Smolts Eggs Pike Mergansers Alien introductions Poaching Breeding Stock Size Net & Rod Catches

  4. Is predation by seals and dolphins significant? • If so, can we do anything about it? • If so, is it cost-effective?

  5. Is predation by seals and dolphins significant? • Carry out an experiment • Use a natural experiment

  6. F 1,9 = 6.35, p < 0.05, r2 = 0.41

  7. Is predation by seals and dolphins significant? • Carry out an experiment • Use a natural experiment • Model consumption of salmon • Requires info on predators’ • population size diet food consumption

  8. A little of what we know, and a lot of what we don’t Bottlenose Dolphin Harbour Seal Grey Seal

  9. 2001 UK population ~ 130,000 (+/- 15%)

  10. Movements of satellite tagged grey seals caught in the Moray Firth Seasonal changes in haul-out counts 1988 1989

  11. 129 individuals (95% Confidence Limits = 110 - 174)

  12. 1990-1995 1996-2000

  13. UK population ~ 50,000 Moray Firth ~ 1,000

  14. Moray Firth Trends 1200 1100 August Moult counts 1000 900 MEAN COUNT ( +/- s.e. ) 800 700 June/July Pupping Counts 600 500 1988 1990 1992 1994 1996 1998 2000 2002 2004

  15. Grey & harbour seal diet

  16. Year-to-year variation of clupeids in harbour seal winter diet

  17. . • Is predation by seals and dolphins significant? Food Climate variation/change Killer whales Cormorants Porpoises Goosanders Food Cod Seals Dolphins Parr Smolts Eggs Pike Poaching Mergansers Breeding Stock Size Net & Rod Catches

  18. 0.5 0.4 Probability 0.3 0.2 0.1 0.0 0 1 2 3 4 5 6 7 • Is predation by seals and dolphins significant? • If so, can we do anything about it? • If so, is it cost-effective?

  19. http://www.abdn.ac.uk/zoology/lighthouse http://smub.st-and.ac.uk/

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