is little evidence from wild populations for a direct cause and 

 effect relationship. There is no conclusive evidence that shell 

 disease causes fluctuations in crustacean populations in the New 

 York Bight apex . 



° Evidence has been published that shows an 

 association between habitat degradation and shell disease . High 

 prevalences of both shell disease and the black gill syndrome 

 have been found in crustaceans from polluted sites. Black gill 

 and shell disease have also been noted after experimental 

 exposure of crustaceans to heavy metals such as cadmium, and to 

 biocides, petroleum, and petroleum derivatives. Both diseases 

 have been reported from the New York Bight apex. 



The only conclusion that can be made about the situation 

 near the 106 Mile Site is that shell disease may be a problem 

 insofar as the marketability of diseased crabs and lobsters is 

 concerned. However, there is no conclusive evidence to associate 

 shell disease in offshore populations with sludge dumping 

 activities at the 106 Mile Site . 



6 . RECOMMENDATIONS 



To extend and verify the conclusions reached by the Working 

 Group, the following actions are recommended : 



° Since shell disease in crustaceans may be influenced by 

 a number of environmental factors -- natural and man- 

 induced -- a continuing monitoring effort is necessary 

 to determine prevalences and severity of disease in 

 species of economic importance. This effort should 

 take into account seasonal, behavioral, and 

 physiological changes in the hosts. The sampling 

 pattern should include polluted and reference sites, 

 and should be stratified by data on salinity, depth, 

 and extent of pollution, as measured by levels of 

 contaminants and presence of specific indicators in 

 sediments, bottom water, and host tissues. As part of 

 the monitoring plan, criteria should be developed to 

 rank severity and type of disease for each species 

 studied. 



° Critical to a full understanding of shell disease are 

 further experimental studies , particularly those 

 concerned with identification of specific 

 microorganisms capable of pathogenesis, experimental 

 manipulation of possible predisposing environmental 

 factors, and the immunologic response of hosts to shel l 

 disruption . 



To accomplish these general objectives, the Working Group 

 proposes a short- and long-term research program oriented toward 

 understanding shell disease in crustaceans of the New York Bight ; 



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