SINDERMANN: POLLUTION-ASSOCIATED DISEASES AND ABNORMALITIES 



Young and Pearce ( 1975) with crabs and lobsters. 

 All layers of the exoskeleton were eroded; affected 

 portions were brittle and easily fragmented; 

 cracking and pitting of calcified layers occurred; 

 and underlying tissues were often necrotic. 

 Laboratory experiments using seawater from the 

 highly polluted inner New York Bight resulted in 

 appearance of the disease in 509f of individuals. 

 Erosion was progressive, crippled individuals 

 were cannibalized, and eroded segments of append- 

 ages did not regenerate after ecdysis. No disease 

 signs developed in control animals held in arti- 

 ficial seawater. 



A German study of the effects of industrial 

 wastes on the brown shrimp, Crangon crangon 

 (Schlotfeldt 1972), disclosed high prevalence of 

 so-called "black spot disease," with signs very 

 similar to those seen in C. septemspinosa from the 

 New York Bight. Juvenile and adult shrimps from 

 the Fohr Estuary had black areas of erosion on the 

 carapace and appendages, with necrosis of under- 

 lying tissues, and, frequently, missing terminal 

 segments of appendages. The disease condition 

 varied in prevalence seasonally, with a peak of 

 8.9^f in summer. Lesions persisted and worsened 

 after ecdysis, and experimental exposure to deter- 

 gent accelerated the course of the disease. 



Shell disease of Crustacea has been observed in 

 many species and under many conditions, both 

 natural and artificial (Rosen 1970; Sindermann 

 1970). Actual shell erosion seems to involve activ- 

 ity of chitinoclastic bacteria, with subsequent 

 secondary infection of underlying tissue by facul- 

 tative pathogens. Initial preparation of the exo- 

 skeletal substrate by mechanical, chemical, or mi- 

 crobial action probably is significant; thus high 

 bacterial populations and the presence of contam- 

 inant chemicals in polluted environments, as well 

 as extensive detrital and epibiotic fouling of gills, 

 could combine to make shell disease a common 

 phenomenon and a significant mortality factor in 

 crustaceans inhabiting degraded environments. 



There is much room for study in this cloudy 

 territory at the boundary between infectious and 

 noninfectious disese processes, as exemplified by 

 fin and shell erosion. This is the area where en- 

 vironmental stress and facultative microor- 

 ganisms exert their impacts; where high bacterial 

 populations in eutrophic waters interact with ex- 

 posed, or injured, or chemically modified surface 

 membranes; where epibiotic fouling organisms 

 can assume pathogenic roles; and where 



nonspecific lesions such as fin rot and skeletal 

 erosions can occur in epizootic proportions. 



Lymphocystis 



While fin erosion, ulcers, and shell disease seem 

 to have reasonable associations with degraded en- 

 vironments, it is difficult to find additional good 

 examples in the category of "Diseases caused by 

 facultative pathogens." Probably the most likely 

 candidate (in an obviously poor field) would be 

 lymphocystis, a virus disease which causes ex- 

 treme hypertrophy of fibroblast cells in a large 

 number of freshwater and marine fishes, and 

 which has been postulated to be associated with 

 environmental stresses. Perkins et al. (1972) 

 found in a 1971 survey that three diseases — 

 lymphocystis, epidermal ulcers, and fin 

 erosion — were abundant in plaice and dab from 

 the Northeast Irish Sea. Lymphocystis infection 

 levels in individual trawl catches ranged from to 

 2b^( in plaice and from to 17^^ in dab. The au- 

 thors pointed out that the Irish Sea has been used 

 recently for dumping of toxic wastes, particularly 

 PCB's, but their concluding statement is 

 ". . . there is insufficient evidence to be certain 

 whether the increased incidence of the diseases 

 noted in 1971 is the result of an outbreak of 

 epidemics of purely biological origin or if the 

 dumping of toxic wastes is responsible." 



Another survey of lymphocystis in the Irish Sea, 

 this one in 1972, was reported by Shelton and 

 Wilson ( 1973). They found lymphocystis to be the 

 most abundant of observable pathological condi- 

 tions, with highest prevalence ( 14.6*^ ) in flounder, 

 Platichthys flesus, and lesser prevalences in other 

 flatfish (1.97f in plaice and 1.1% in dab). Unlike 

 Perkins et al. ( 1972), Shelton and Wilson consid- 

 ered recent pollution of the Northeast Irish Sea to 

 be the least likely explanation for high .levels of 

 lymphocystis — pointing out that the disease has 

 been known from that area for 70 yr, having been 

 described early in the century by Woodcock ( 1904) 

 and Johnstone ( 1905) from flounders taken in the 

 Irish Sea. Van Banning ( 197 1 ) studied lymphocys- 

 tis in North Sea plaice (Figure 5) and also con- 

 cluded that pollution was not a likely cause of high 

 prevalences. 



A recent lymphocystis epizootic with over 50% 

 prevalence was reported from flatfish in the North 

 Sea by Mann (1970) and earlier epizootics have 

 occurred in Europe (Weissenberg 1965). Temple- 

 man (1965) reported an epizootic in American 



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