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Unformatted text preview: ESM 242: Assignment #1 Due in class Tuesday April 17, 2007 1 Recreational Abalone Diving Here we consider recreational abalone diving off the coast of Northern California. In this question we’ll develop and analyze a simple stylized model to assess the impact of various policy changes in the sport abalone fishery. Consider the following population growth model: N t +1 = N t + rN t 1- N t K- H t (1) where N t is the biomass of abalone, r = 0 . 2 is the intrinsic growth rate, K = 1000 is the carrying capacity of the abalone population, and H t is the harvested biomass in year t . 1. Identify the variable(s) and the parameter(s) of this model. 2. Suppose the abalone stock is severely depressed; say it is at 10% of the carrying capacity. Write a program in Excel to simulate the abalone population size over a 25 year period without harvest (i.e. if the fishery is shut down). Graph the recovery over time. Suppose we say that a population is “recovered” when it reaches 90% of carrying capacity. In what year did this population “recover”? Graph the “recovery” time as a function of the intrinsicyear did this population “recover”?...
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- Spring '07
- Population Ecology, ht, abalone population