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Fishery Bulletin 101(3) 



For the catch-per-trip configurations, catch rates were best 

 characterized by the negative binomial di.stribution (Table.s 

 5-6, Figs. 5-6). Note that the calculated ehi-square, G-. and 

 D-test statistics were generally significant at the 1% level, so 

 that based on strict interpretation of these results, the null 

 hypothesis that the observed distributions come from one of 

 the theoretical distributions was rejected in all cases. How- 

 ever, the calculated test statistics for the negative binomial 

 distributions were at least an order of magnitude smaller 

 than those for the Poisson and lognormal distributions, sug- 

 gesting that an underlying negative binomial distribution 



was much more likely. The distributions of the catch-per- 

 hour rates generally had a truncated range compared to 

 the catch-per-trip rate configurations (Figs. 1-4). For most 

 of the catch-per-hour distributions, the maximum likelihood 

 solution for the negative binomial k parameter occurred at 

 very large values (>1000). The expected frequencies for the 

 negative binomial distribution therefore converged to those 

 expected for a Poisson distribution, resulting in identical test 

 statistic values and indicating that the catch-per-hour rates 

 are best characterized by the Poisson distribution (Tables 

 7-8, Figs. 7-8). 



