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Fishery Bulletin 103(2) 



dynamics rather than on exploring all possible param- 

 eter combinations. However, it would certainly be use- 

 ful in the future to examine the same question using 

 parameter estimates based on other commercially ex- 

 ploited species that change sex. 



Results 



We present the average across simulations of the mean 

 population measures of the last 50 years for each simu- 

 lation. The variation around the mean in all measures 

 considered is hundredths of a percent of the mean or 

 less. For the spawning-per-recruit (SPR) measures we 

 give the mean value across the first 50 years of fishing 



to ensure that the entire cohort under consideration had 

 died before the end of the simulation. Parameter values 

 used are given in Table 1 



General dynamics 



In all cases, size-selective fishing is predicted to decrease 

 population size and decrease the mean length offish in 

 the population. Although all scenarios are predicted 

 to lead to the same change in average fish length, the 

 effect of fishing on predicted population size and the 

 mechanisms leading to changes in population size 

 differ between the four sex-change rules (Figs. 1 and 2, 

 Table 2). The largest differences occur between the fixed 

 rule and the three plastic patterns of sex change. How- 



