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howework_7 - Homework #7 WFC 10 Gary Rossetto Unfished...

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Homework #7 WFC 10 Gary Rossetto 1. The graphs above, from Dr. Botsford’s lecture, show the relative age and abundance of fish in a population when it is fished and when it is not. The population starts at 1.0 (100% of individuals) and in each successive year, the proportion of the original population that survives declines. For example, in the unfished population the proportion left at the end of year 1 is about 0.8 or 80%. Dr. Botsford likens egg production in fish to interest in a bank account, where the largest and oldest individuals produce the most eggs (high interest rate). If you protect large fish, you have a higher interest rate, but you harvest fewer fish initially (less cash to buy a new car). a. If in the above population, egg production per female is low until each female reaches 10 yrs old, what will happen to the fished population if fishing continues? The population will decrease exponentially. There will be less fish producing eggs each year, and therefore, a higher percentage of the population will be harvested each year. There is a
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This note was uploaded on 04/30/2008 for the course WFC 10 taught by Professor Moyle during the Spring '08 term at UC Davis.

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howework_7 - Homework #7 WFC 10 Gary Rossetto Unfished...

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