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Seals, dolphins & salmon in the Moray Firth

Explore the impact of seals and dolphins on salmon populations in Moray Firth. Analyze predation significance, conduct experiments, and discuss solutions. Discover population dynamics and dietary habits of key predators.

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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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