1 / 29

Projected changes to coastal fisheries

Projected changes to coastal fisheries . Based on. Outline. Main components of coastal fisheries Indirect effects of climate change Direct effects of climate change Projected changes to coastal fisheries production Priority management measures . C oastal fisheries catch – Cook Islands.

lilac
Download Presentation

Projected changes to coastal fisheries

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Projected changes to coastal fisheries

  2. Based on......

  3. Outline • Main components of coastal fisheries • Indirect effects of climate change • Direct effects of climate change • Projected changes to coastal fisheries production • Priority management measures

  4. Coastal fisheries catch – Cook Islands Commercial Subsistence Source: Gillett (2006)

  5. What are coastal fisheries? • Demersal fish • Nearshorepelagics • Invertebrates Species not considered • Deepwater snapper • Sharks

  6. Demersal fish

  7. Nearshore pelagic fish

  8. Invertebrates

  9. Coastal fisheries catches – Cook Islands 14 t/yr 146 t/yr 240 t/yr Pratchett et al. 2011

  10. Demersal fish catch composition Availability Catch Percentage Pratchett et al. 2011

  11. Indirect effects of climate change % Coral cover Area (km2)

  12. 65% decline in abundance and diversity of fishes

  13. Effects of habitat degradation 0.5 0 -0.5 -1 Macroalgae Proportional change Habitat complexity Coral cover 0 1 2 3 4 5 6 7 8 9 10 Time after extensive coral loss (years)

  14. Effects of habitat degradation 50 0 -50 -100 Macroalgae Percentage change Habitat complexity Coral reef fishes Coral cover 0 1 2 3 4 5 6 7 8 9 10 Time after extensive coral loss (years)

  15. Catch composition GeneralistsNot vulnerable Reef associatedVulnerable Coral associatedHighly vulnerable

  16. Importance of herbivorous fish

  17. Herbivorous fish in Cook Islands Availability Catch Percentage

  18. Direct effects of climate change pH Temperature

  19. Effects of temperature Growth (mg/week) Damsel fish (Acanthochromispolyacanthus) Maximum growth 28-30oC Projected increase 3oC by 2100 Temperature (oC) ZarcoPerello and Pratchett 2012

  20. Effects of temperature • Declines in: • growth • lifespan • reproduction Fewer & smaller fishes Growth (mg/week) Maximum growth 28-30oC Projected increase 3oC by 2100 Temperature (oC) ZarcoPerello and Pratchett 2012

  21. Effects of temperature Normal spawning temperature

  22. Effects of ocean acidification Abalone Byrne 2012

  23. Effects of ocean acidification Munday et al. 2012

  24. Projected coastal fisheries productionCook Islands *Based on initial preliminary modelling for skipjack tuna

  25. Ciguatera fish poisoning

  26. Factors affecting ciguatera • Dead coral & seaweed surfaces • Nutrients • Water temperature From land-based activities and sewage

  27. Priority management measures • Protect structural complexity and biological diversity of coral reefs to sustain fisheries • Maintain adequate spawning stocks to help overcome shocks of greater climate extremes • Recognise ecological importance of herbivorous fish and ensure stocks are sufficient to maintain ecosystem functions

  28. Conclusions • Coastal fisheries are important for food security and livelihoods • Effects of climate change will add to existing pressures (e.g. overfishing) • Improved catch data are needed for monitoring effects of climate change on coastal fisheries: • separate data for each main category of coastal fisheries • subsistence fisheries catches

More Related