BIO 15b Ovefishing

BIO 15b Ovefishing - Three things effecting bio-diversity...

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Three things effecting bio-diversity 1. habitat destruction* 2. introduced species 3. overexploitation* Overfish: To deplete the stock of fish, shellfish, etc. , in a body of water by too much fishing. Stock: A group of individuals in a species occupying a well defined spatial range independent of other stocks of the same species “a stock that is subject to overfishing has a fishing mortality (harvest) rate above the level that provides for the maximum sustainable yield” NMFS Reports to Congress: 20% of stocks were subject to overfishing; if mortality rate is higher than sustainable yield then number of fish will go down every year. Fishing Bay from Cape Cod to George’s Bank When you take out key elements of food webs, it affects the rest. Cod fish went down and the seals came in because they use to compete for the same fish. Same fish populations are also increasing because their predators (the cod fish) is gone. And the plants that the small fish also grow. This makes it hard for the cod fish
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This note was uploaded on 05/02/2008 for the course BIOL 15b taught by Professor Neil during the Spring '08 term at Brandeis.

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BIO 15b Ovefishing - Three things effecting bio-diversity...

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