Econ 131 lecture 16

Econ 131 lecture 16 - Schedule Today Fisheries After...

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Schedule Today: Fisheries CAPE evaluations online After Thanksgiving Tuesday: Economics of water resources Thursday: Chapter 12 (summary) and policy examples for review Fisheries Similar to forests in some ways: Fish stocks grow naturally and we need to decide how many to catch to maximize the value of the resource
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Fisheries As 15% of global protein intake there are many good reasons for economists and biologists to study them Like forests, they are a renewable resource and there exists a biological optimum: “Maximum sustainable yield” (MSY) Like forests, there is also an economic optimum that involves harvesting less ±sh Unlike forests, it is due to a production externality that we can examine in an economic model of the ±shery Many Fisheries in Trouble
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Sources of Stock Decline Overharvesting Bycatch (more than a third of the catch in most cases) Habitat Harm Harm to coral reefs (breeding area, source of nutrients) Harm to estuaries (reduction in freshwater Fows) Water pollution Bycatch Statistics Drift nets At peak, ensnared 42 million untargeted ±sh, marine mammals, and sea birds each year Longlines Can be up to 80 miles long with 3,000 baited hooks Cause of serious declines in sword±sh, bill±shes, sharks, and sea turtles
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Habitat Harm Coral Reefs Pollution Use of dynamite or cyanide to stun Fsh Global warming Estuaries Important to 75% of Fsh caught in U.S. Dams Other reductions in freshwater ±ows Economics of ²isheries Open access Fsheries will be overharvested, resulting in a collapse (e.g. in the paciFc tuna Fsheries) An economic model can be used to describe the underlying source of the problem, and suggest mechanisms to fx it
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The Bioeconomic Model The “bio” part of the model: Logistic growth Like a production function: effort (economic inputs) and the stock combine to determine catch (economic output)
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This note was uploaded on 01/30/2012 for the course ECON 131 taught by Professor Groves during the Spring '09 term at UCSD.

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Econ 131 lecture 16 - Schedule Today Fisheries After...

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