1.0 INTRODUCTION 



Shell disease in the broad sense of the term, includes a 

 diverse array of shell abnormalities ranging from unsightly black 

 discoloration to open or perforating lesions. The condition may 

 affect the carapace or shell as well as the legs or claws, and 

 has been reported in numerous freshwater and marine species of 

 economic importance, i.e., lobsters, crabs, shrimp, crayfish and 

 prawns (Sindermann, 1989). Shell disease may result from 

 mechanical damage due to wounds or abrasions that permit invasion 

 by chitin destroying bacteria or fungi, or from overcrowding and 

 contact with infectious organims that may gain access to the 

 shell through surface pores. The disease in natural or "wild" 

 populations usually occurs at low levels, but may be enhanced by 

 (1) overcrowding in traps or discard handling during commercial 

 fishing operations, which increase the likelihood of shell 

 damage, (2) stresses from unhealthy environments, or (3) high 

 organic loading of containment waters which contributes to the 

 multiplication of microorganisms, some of which may be pathogenic 

 to crustaceans. 



Shell disease has been observed in shrimp, crabs, and 

 lobsters from badly degraded coastal/estuarine waters, often in 

 association with black discoloration of the gills. Erosion of 

 the exoskeleton and odors of hydrogen sulfide or petroleum have 

 been noted in animals taken with contaminated sea bottom 

 sediments. Experimental exposure of crustaceans held in aquaria 

 with sediments from sewage sludge or contaminated dredge material 

 sites leads to mortality and/or enlargement of areas affected by 

 black discoloration or shell erosion. Shell disease therefore, 

 is a particular problem in impoundments, aquaculture facilities, 

 and in degraded habitats. It is complex, contagious, and may be 

 caused by a diverse group of microorganisms and environmental 

 stressors. The condition may contribute to mortality, 

 principally by providing a route of entry for facultative 

 pathogens; severe disease may damage gill tissue and interfere 

 with respiration and may also interfere with molting. Sick or 

 weakened animals may die prematurely, or be consumed by 

 predators. Advanced signs of shell disease are of concern to the 

 fishing industry because of unsightly conditions that affect the 

 marketability of whole animals, legs, or claws. 



Shell disease and/or gill blackening has been recognized in 

 crabs, lobsters, and shrimp caught in waters of the New York 

 Bight apex near New York and New Jersey, Present concerns are 

 focused on reports of shell disease affecting commercial catches 

 of crabs and lobsters from waters in proximity to the 106 Mile 

 Site. The 106 Mile Site, located off the continental shelf, is 

 south of the Hudson Canyon, approximately 187 km from the 

 entrance of New York Harbor (see Figs. 1 and 2). Water depths 

 range from 1700 to 2750 m and average about 2200 m. Industrial 

 wastes, sewage sludge, and fly ash have been deposited in the 

 area in the past and it now receives over 8 million wet tons of 

 sludge annually (see Appendix 3). 



