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Fishery Bulletin 91(4), 1993 



Biomass and number test statistics for butterfish in 

 spring cruises were significantly different between pre- 

 and post-dumping periods in the northern region, but 

 not significantly different in the southern region. Con- 

 versely, those statistics from autumn cruises were not 

 significant in the northern region, but significant in 

 the southern region. Test statistics for spiny dogfish 

 showed similar patterns (Table 1). Species abundance 

 indices for butterfish and spiny dogfish fluctuated, but 

 generated much higher values for the test statistics 

 than did those of other species (Tables 4-7). Accord- 

 ingly, interpretation of the butterfish and spiny dog- 

 fish statistics suggests a positive difference in these 

 two species over time. 



In spring cruises, test statistics in CPUE both by 

 weight and number for goosefish, scup, longfin squid, 

 American lobster, and silver hake were not significantly 

 different for pre- and post-dumping periods for either 

 the north or south region, with exception of silver hake 

 number indices in the north region. For autumn cruises, 



however, there were significant differences between pre- 

 and post-dumping periods for goosefish, scup, and 

 longfin squid (Table 1). Abundance indices for goosefish 

 declined from the pre- to the post-dumping period for 

 both cruises and regions. Longfin squid indices declined 

 from the pre to the post period in spring cruises, but 

 increased in autumn cruises. All scup indices declined 

 but increased in autumn cruises within the south re- 

 gion. American lobster indices showed little change 

 between pre- and post-dumping periods. Silver hake 

 indices increased in spring cruises but declined in au- 

 tumn cruises from the pre to post period (Tables 4-7). 

 The lower abundance indices of these species may sig- 

 nify that the populations responded negatively to ad- 

 verse differences. 



In spring cruises, CPUE statistics for all species, 

 both by biomass and number, were significantly differ- 

 ent between pre- and post-dumping periods in both 

 regions. This occurred though test statistics for some 

 individual species were significantly different and 



