Chang: Effects of sewage sludge clumping on fishery resources 



607 



certain food-web dynamics for commercially important 

 fisheries resources in the New York Bight are becom- 

 ing known (Steimle, 1985; Steimle and Terranova, 

 199H. Chemical analyses of sediment cores tend to 

 confirm that sediment chemical concentration around 

 the 12-MDS is related to some types of dumping, and 

 that sediment concentrations decrease appreciably in 

 some areas 20 months after cessation of sewage sludge 

 dumping (Zdanowicz et al., 1993 24 ). Distribution of the 

 contaminant-sensitive and insensitive benthic inverte- 

 brate species assemblages in the New York Bight 

 (Chang et al., 1992) then imply that material dumped 

 at the 12-MDS reached the bottom in the area where 

 it was dumped, entered the food-web at the lower 

 trophic levels of benthic organisms, and ascended to 

 the higher trophic levels of predatory fish species 

 (Steimle et al. 25,26 ). Similar food-web dynamics could 

 have influenced the temporal and spatial differences 

 in abundance of commercially important species mea- 

 sured in the principal area of sludge influence at the 

 106-MDS. 



Conclusions 



Effects of sewage sludge dumping even in the deep 

 ocean at the 106-MDS, like sludge dumping at the 12- 

 MDS in the New York Bight and release of sewage 

 from outfalls in southern California outfalls, cannot be 

 excluded as a factor measurably affecting fishery re- 

 source abundance and composition. Natural factors may 

 have caused the population fluctuation assessed around 

 the 106-MDS, but there are no adequate data sets for 

 testing the likelihood that such phenomena, and not 

 deepwater dumping, are responsible. Data sets are even 

 more inadequate for measuring interactive effects of 

 dumping, fishing, and natural phenomena, which must 

 certainly occur. On the other hand, there are identifi- 

 able mechanisms by which changes in abundance and 



24 Zdanowicz, V. S., S. Leftwich. and T. W. Finneran. 1993. Reduc- 

 tions in sediment metal contamination in the New York Bight apex 

 with cessation of sewage sludge dumping. In A. L. Studholme, J. 

 O'Reilly and M. C. Ingham (eds.), Effects of the cessation of dump- 

 ing at the 12-mile site. U.S. Dep. Commer., NOAA, Natl. Mar. Fish. 

 Serv., Northeast Fish. Sci. Cent., Sandy Hook Lab., Highlands, NJ, 

 14 p. (In review.) 



-^Steimle, F. W. Jr., V. S. Zdanowicz, S. L. Cunneff. and R. Terranova. 

 1993a. Trace metal concentrations in common benthic macrofaunal 

 prey from New York Bight apex. U.S. Dep. Commer., NOAA, Natl. 

 Mar. Fish. Serv, Northeast Fish. Sci. Cent., Sandy Hook Lab., High- 

 lands, NJ. 21 p. (In review.) 



26 Steimle, F. W. Jr., D. Jeffress, S. A. Fromm, R. N. Reid. J. J. 

 Vitaliano, and A. Frame. 1993b. Prey selectivity by winter flounder 

 Pleuronectes americanus in the New York Bight apex. LIS. Dep. 

 Commer., NOAA, Natl. Mar. Fish. Serv, Northeast Fish. Sci. Cent., 

 Sandy Hook Lab., Highlands, NJ, 28 p. (In review.) 



composition of fishery resources could have come about 

 in relatively few years as a result of sludge dumping 

 after prior years of industrial and chemical waste dis- 

 posal at this deepwater site. Increased contamination 

 of the food-web and environment could well have di- 

 rectly and indirectly, possibly differentially, affected 

 both behavior and reproduction of ecologically linked 

 species leading to the unfavorable temporal, spatial, 

 and seasonal differences of the fishery resources around 

 the 106-MDS. 



Analyses of bottom trawl surveys and fishery land- 

 ings data in relation to environmental pollution are of 

 increasing importance as efforts are made to measure 

 any impact of toxic contaminants on fishery resource. 

 The influence of natural and man-induced environmen- 

 tal factors, such as waste dumping, on fishery resources 

 can be treated as concomitant variables (Thomas et 

 al., 1976; Butler and Schutzman, 1979; Marking and 

 Kimerle, 1979; Geyer, 1981, a and b; Reed et al., 1985; 

 Miller et al.. 1988; Wallace et al., 1988; Stoddard and 

 Walsh, 1988; Connor, 1989; Gift et al., 1989; Stanford 

 and Young, 1988, Furness and Rainbow, 1990; Word et 

 al, 1990; Manning, 1991). Interpretation of fishery as- 

 sessment data in relation to the sewage sludge dump- 

 ing at the 106-MDS, as developed in the discussion 

 above, makes clear that future efforts in all these re- 

 gards would benefit from better and updated baseline 

 data on the fishery resources. If there were food-web 

 dynamics data as well as more behavioral and repro- 

 ductive data on responses of marine fish to contami- 

 nant levels known to occur in the ecosystems of con- 

 cern, we would then be better able to understand and 

 determine causal factors influencing species abundance 

 and fishery resources in the vicinity of the 106-MDS 

 and adjacent continental shelf waters. Much is still to 

 be learned about both the natural fluctuation of envi- 

 ronmental factors that influence species abundance and 

 population dynamics and about anthropogenic effects 

 on the natural environment. A better understanding 

 of natural and man-induced effects on fishery resources 

 is necessary to minimize adverse controllable impacts 

 on fisheries resources and requires further synthesis 

 of environmental and fishery assessments. 



Acknowledgments 



I would like to acknowledge the contribution of scien- 

 tists from Resource Surveys Investigation, Conser- 

 vation and Utilization Division, Northeast Fisheries 

 Science Center. Their efforts and perseverance in the 

 collection of bottom trawl survey data and maintenance 

 of the survey data system produced the extensive data 

 base used for the analysis in the paper. 



