rarely observed in shrimp examined from waters of the Beaufort, 

 North Carolina and the Woods Hole, Massachusetts region. All 

 layers of the exoskeleton in affected shrimp were eroded, 

 affected portions were brittle and easily fragmented; cracking 

 and pitting were noted in calcified layers, and underlying 

 tissues were often necrotic. Laboratory experiments using sea 

 water from the highly polluted inner New York Bight resulted in 

 shell disease in 50% of the test animals. Erosion was 

 progressive, crippled individuals were cannibalized, and eroded 

 segments of the appendages did not regenerate after molting. 

 Disease signs did not develop in control animals held in 

 artificial seawater. Other evidence for a relationship between 

 shell disease and pollution was presented by Pearce (1971, 1972) 

 and Young and Pearce, (1975). Based on field collections and 

 experimental studies, they concluded that "crabs and lobsters 

 collected from the vicinity of sewage sludge and dredge spoil 

 disposal areas within the New York Bight apex most frequently 

 showed skeletal erosions ..." Furthermore, they reported that 

 normal animals exposed to sewage sludge from disposal sites 

 developed exoskeletal lesions within six weeks, and that eroded 

 gills were of particular note. 



In contrast to existing knowledge, where specific causes of 

 shell disease have been documented, it is apparent that multiple 

 causes of disease should be investigated in animals residing in 

 both clean and stressed environments. One of the most immediate 

 concerns, with regard to pollution-related causes of shell 

 disease, should focus on whether or not chemical pollutants 

 compromise chitin deposition and shell mineralization, rendering 

 the exoskeleton more susceptible to chemical degradation and/or 

 destruction by lytic microorganisms. Current knowledge suggests 

 that there is a definite, though unquantif ied, relationship 

 between environmental pollution and the prevalence of shell 

 disease. With few exceptions, existing sampling techniques have 

 not been applied to the biota of the 106 Mile Site and canyons of 

 the continental shelf. 



Concerns expressed by commercial fishermen suggest that 

 crabs and lobsters may now have unusually severe signs of shell 

 disease. However, data are not available to support or deny 

 recent increases in this form of the disease. Specific 

 indicators of sewage pollution such as viruses, bacteria, 

 protozoa, and coprostanol are present in sediments of the New 

 York Bight apex, and high prevalences of shell disease have been 

 reported. Only limited studies of similar contaminants have been 

 made on deepwater offshore sediments. No direct evidence exists 

 to support claims that pollution is associated with shell disease 

 in offshore crustacean populations. 



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