12_ Outline Human Impacts on Ecosystems09

12_ Outline Human Impacts on Ecosystems09 - BSCI 106 Dr....

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BSCI 106 Fall 2009, p. 1 Dr. Sara Via Lecture 12- Human Impacts on Communities and Ecosystems A. Impacts on communities 1. Overfishing a. cod fishery in Northeast is essentially gone b. halibut, other large fish now greatly reduced c. much of the fish now caught was considered junk 50 years ago d. 1998: article in Science magazine says humans are “fishing down marine food webs as larger and more commercially valuable species disappear, creating impoverished, less valuable ecosystems. in 30-40 years, we will have 'a marine junkyard' dominated by plankton”. 2 . Case study: Bluefin Tuna in Mediterranean a. Bluefin Tuna is large, slow growing very migratory species b. extremely valuable c Mediterranean fishery exceeds “regulation” limits - not enforced, or even enforceable - small tuna caught, taken to "fattening pens" d. World Wildlife Fund- predicts imminent extinction 3. Solutions to overfishing? Regulation and enforcement a. regulate catch -amount - fish size - impose time of year restrictions
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This note was uploaded on 10/05/2009 for the course BSCI 106 taught by Professor Porter during the Fall '08 term at Maryland.

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12_ Outline Human Impacts on Ecosystems09 - BSCI 106 Dr....

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