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Biology 1229 Fisheries… or… Should fish be on the menu?

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Presentation on theme: "Biology 1229 Fisheries… or… Should fish be on the menu?"— Presentation transcript:

1 Biology 1229 Fisheries… or… Should fish be on the menu?

2 Fish on the menu…  At least 2.5 Billion people depend on fish for more than 20% of the protein in their diet  97 % of fishers are in developing countries

3 Why might fish be on the list?  Mercury

4 Why might fish be on the list?  Farming practices unsustainable Shrimp farming in Mexico destroys mangrove forests Salmon farming  Escapes  Parasites  Eutrophication

5 Why might fish be on the list?  Fishery unsustainable or environmentally damaging Bottom trawling Bycatch from a shrimp net!

6 Unsustainable fisheries

7 How does a harvested population work?  Note: “sustainable” is economic, not based on the population!!!  It is possible to derive a MSY from population data using growth rate and harvest rate

8 Orange Roughy Hoplostethus atlanticus  Slow, ugly, demersal fish (“Slimehead”)  Mature at 20-30  Live up to 156 years (depending on who you listen to…)  Harvested by bottom trawling around sea mounts  Fishing, or mining?

9 How much of the ocean is harvested?

10 Fishing down the food web

11 How many fisheries are sustainable?

12 What about recreational fishing? Commercial Fishery Recreational fishery as a %age of commercial Including menhaden and pollock But the vast majority of several high-value, threatened species (e.g. Red Snapper) are caught recreationally

13 We are catching too many fish!!

14 Not just fish suffer…  Effects on seabirds & other top predators  Effects on erosion and flood control (e.g. New Orleans)  Economic effects of fishery collapse (Newfoundland)

15 Top 20 countries for unsustainable fishing… 1. China 2. Peru 3. Japan 4. Chile 5. USA 18. Canada

16 What future?  Some authors predict the collapse of ALL fisheries by 2048  Sustainable management is possible… requires Reliable data Reliable fisherman A pretty decent navy  End of oil may result in reduced fishery pressure

17 Ownership of fisheries prevents collapse Number of Individual transferable quota (ITQ) fisheries With ITQ Without ITQ

18 See also http://www.mbayaq.org/cr/seafoodwatch.asp


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