604 



Fishery Bulletin 91(4), 1993 



Discussion 



Analyses of fisheries abundance data, based on catch 

 per unit of effort (CPUE) of NOAAs Northeast Fisher- 

 ies Science Center (NEFSC) bottom trawl surveys, in- 

 dicate that abundances of silver hake, red hake, sum- 

 mer flounder, goosefish, and black sea bass declined 

 about the 106-mile dumpsite (106-MDS) from spring 

 of 1982 through spring of 1990. These declines are 

 concurrent with the temporary dumping there of sew- 

 age sludge from the New York and New Jersey metro- 

 politan area. Changes in total abundance and biomass 

 for all species combined occurred to a lesser degree 

 because of increased abundance of spiny dogfish, skates 

 {Raja spp.) and some pelagic species (e.g., Atlantic 

 mackerel) (NMFS 1991, 1992). There were statistically 

 significant, temporal differences in average abundance 



values for some individual species and for all species 

 based on spring and autumn bottom trawl surveys 

 within the north and south dumpsite areas. It is par- 

 ticularly worth noting that much of the abundance 

 decline occurred in the south area of the dumpsite. 

 The south region is most likely to be influenced by 

 sewage sludge introduced in waters passing toward 

 the west-southwest shallow outer shelf through the 

 dumpsite in the potential area of influence (PAIi of 

 the sewage sludge (Fig. 1; Bisagni, 1983; O'Connor et 

 al, 1985; Gentile et al., 1989; Ingham ls ; Warsh 13 ; 

 Bisagni'). There were also statistically significant spa- 

 tial differences in average abundance of many indi- 

 vidual species and all species sampled on the spring 

 and autumn surveys within the pre- and post-dump- 

 ing period at the 106-mile dumpsite. There were sea- 

 sonal differences, as well, in average values for sev- 



