Williams and Shertzer: Effects of fishing on growth traits: a simulation analysis 



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individuals experience differential fishing pressure and 

 therefore the potential for selection differentials. If har- 

 vest had been held constant instead of F, the selection 

 differentials would have been larger. 



The fishing season duration (D F ) affected selection 

 differentials in ways similar to the spawning season 

 duration (Tables 2 and 3, Fig. 5). A fishing season of 

 one month resulted in an upper bound of selection dif- 

 ferentials that ranged from 4.8% to 7.3% over all ages 



(Fig. 5). Of all the fishery parameters examined in this 

 analysis, a concentrated fishing season resulted in the 

 largest selection differentials. 



Discussion 



The individual-based simulation approach used here 

 simplifies computation of selection differentials and 



