Transcript Fish
Biology 1229 Fisheries… or… Should fish be on the menu? 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 Why might fish be on the list? Mercury Why might fish be on the list? Farming practices unsustainable Shrimp farming in Mexico destroys mangrove forests Salmon farming Escapes Parasites Eutrophication Why might fish be on the list? Fishery unsustainable or environmentally damaging Bottom trawling Bycatch from a shrimp net! Unsustainable fisheries 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 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? How much of the ocean is harvested? Fishing down the food web How many fisheries are sustainable? What about recreational fishing? Commercial Fishery Including menhaden and pollock Recreational fishery as a %age of commercial But the vast majority of several high-value, threatened species (e.g. Red Snapper) are caught recreationally We are catching too many fish!! 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) Top 20 countries for unsustainable fishing… 1. 2. 3. 4. 5. 18. China Peru Japan Chile USA Canada 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 Ownership of fisheries prevents collapse With ITQ Without ITQ Number of Individual transferable quota (ITQ) fisheries See also http://www.mbayaq.org/cr/seafoodwatch.asp