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others not. In the autumn cruises, biomass statistics 

 were statistically significant between pre- and post- 

 dumping period cruises, but for the southern region 

 only (Table 1). These results substantiate the negative 

 temporal differences. They suggest a reduction over 

 time for all species abundance and biomass in both 

 regions of the study area. 



Abundance indices for all species in spring cruises 

 decreased from the pre- to the post-dumping periods 

 but increased in autumn cruises. Variabilities for all 

 species were consistently lower (9-24%) than those for 

 individual species ( 18-88% ) (Tables 4-7 ). This suggests 

 that fluctuations in total biomass in the study area 

 from 1982 to 1990 for all species were lower as a whole 

 and masked fluctuations in individual species. One may 

 infer that the impacts of fishing, ecological perturba- 

 tions, or natural factors acting on all species as a whole. 



therefore, were relatively low in the spring. Although 

 impact on the abundance indices for all species was 

 less than on some individual species, there were no 

 significant differences in the number of species be- 

 tween pre- and post-dumping periods in either region. 



Spatial differences 



To assess spatial differences for species CPUE between 

 north and south regions, the same approach was used 

 as for temporal differences. Test statistics for spatial 

 differences are summarized in Table 2 and Tables 4-7. 

 These are based on species CPUE, species abundance 

 indices, and their variability estimates from collective 

 cruises in pre- and post-dumping periods. 



More species test statistics for autumn cruises were 

 significantly different between the north and south 



