Chang; Effects of sewage sludge dumping on fishery resources 



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provided insights into how individual fish and shellfish 

 populations responded in time and space. The variabili- 

 ties were relatively consistent in both regions, despite 

 confounding biotic and abiotic factors. Fluctuations of 

 total biomass for eleven individual species, and for all 

 species as a whole, were relatively stable in both north 

 and south regions during the period 1982-90. 



Seasonal differences 



Seasonal differences between spring and autumn were 

 determined by the same method used to evaluate tem- 

 poral and spatial differences. Test statistics for seasonal 

 differences based on species CPUE and species abun- 

 dance indices with their variability estimates were 

 drawn from collective cruises of the pre- and post-dump- 

 ing periods. They are summarized in Tables 3 and 4-7. 

 Species test statistics for the pre-dumping cruises 

 showed more significant differences between spring and 



autumn seasons than did post-dumping cruises. Weight 

 test statistics provided more significant differences than 

 those based on number. Spiny dogfish CPUE revealed 

 significant test statistics for all categories. Test statis- 

 tics for black sea bass, based on both biomass and 

 number, showed significant differences between sea- 

 sons for the post-dumping cruises in the southern re- 

 gion, but not for the pre-dumping cruises in the same 

 region. Similarly, silver hake, butterfish, and Ameri- 

 can lobster indices in the northern region were signifi- 

 cantly different for the post-dumping cruises, but not 

 significantly different for pre-dumping cruises (Table 

 3). Some species weight abundance indices declined 

 from the pre-dumping to post-dumping periods for both 

 spring and autumn seasons (Tables 4 and 7). These 

 included silver and red hakes, summer flounder, 

 goosefish, and black sea bass. Number of species for 

 the post-dumping cruises in the southern region was 

 also significantly different (Table 3). 



