SUMMARY 



A detailed examination has been made of the available 

 information on shell disease of crustaceans, especially in those 

 from the New York Bight, but including data from other areas as 

 well. The study addressed three key questions: 



(1) Does shell disease constitute a serious problem in 

 crustacean populations of the New York Bight, including 

 continental shelf canyons near the Deepwater Municipal Sludge 

 Dump Site? 



(2) Is shell disease related to pollution? 



(3) Does shell disease result in mortalities of 

 crustaceans? 



Principal findings of the study are these: 



° Shell disease is a natural phenomenon, but it may 

 occur with higher prevalence and greater severity 

 in polluted areas than in those not degraded by 

 man^s activities . Shell disease represents a 

 stage in the natural relationship between 

 crustaceans and chitin-utilizing microorganisms. 

 The balance between metabolic processes associated 

 with new shell formation, and infection by 

 microbes capable of utilizing chitin, may be 

 disturbed by environmental changes affecting 

 normal shell formation or favoring the growth of 

 chitin-utilizing microbes. Such disturbances may 

 be consequences of pollution. 



° Evidence exists for an association of shell 



disease with habitat degradation . Prevalences 

 have been found to be high in crustaceans from 

 polluted sites; prevalences show trends similar to 

 those of the black gill syndrome, which also has a 

 statistical association with extent of pollution. 

 Experimental exposures of crustaceans to 

 contaminated sediments, heavy metals, biocides, 

 petroleum, and petroleum derivatives can result in 

 the appearance of the black gill syndrome, often 

 accompanied by shell disease. Studies in the New 

 York Bight apex have disclosed the presence of 

 shell disease in lobsters, crabs, and shrimp 

 (Crangon) . Reference sites sampled for shrimp 

 showed the prevalence of shell disease to be much 

 lower there than in apex samples, but similar data 

 for crabs and lobsters from reference sites should 

 be collected. 



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