SINDERMANN: POLLUTION-ASSOCIATED DISEASES AND ABNORMALITIES 



The report on ulcerations and fin rot in winter 

 flounders from Narragansett Bay, by Levin et al. 

 (1972) has been mentioned in the previous section. 

 The acute ulcerative lesions were thought to be 

 caused by V. anguillarum infections, and the ul- 

 cerative phase was reproduced in fish exposed ex- 

 perimentally to cultured V. anguillarum isolates. 



A more recent report by Robohm and Brown 

 (1977) described systemic bacterial infections and 

 ulcerative lesions of the tail and dorsal muscles in 

 summer flounder from Connecticut waters. A 

 highly pathogenic Vibrio sp. was isolated, and ex- 

 perimental infections were produced by sub- 

 cutaneous inoculation and by seeding holding 

 tanks with bacteria at levels of 360/ml. Ulcers at 

 the inoculation site and subcutaneous hemor- 

 rhages along the bases of fins characterized ex- 

 perimental infections (Figure 3). These observa- 

 tions resemble those of Levin et al. (1972) in 

 winter flounder. 



Ulcerations, probably of bacterial etiology, have 

 been reported in fish of several species from the 



Irish Sea. Perkins et al. (1972) and Shelton and 

 Wilson (1973) reported ulcers from European 

 flounders (Platichthys flesus), dab, and plaice. 

 Prevalences were low (1-49^) in most instances. 



An "ulcer syndrome" in cod, Gadus morhua, 

 from Danish coastal waters has been studied for 

 several years and seems associated with localized 

 areas of severe pollution (Jensen and Larsen 1976, 

 1977; Larsen and Jensen 1977a, b). Vibrio anguil- 

 larum and anAeromonas species have been impli- 

 cated (S^rensen 1977). 



Ulcerations or external lesions on fish may, of 

 course, have a number of causes other than bacte- 

 rial infection. They may be due to net damage or 

 other surface abrasions, or to predator attacks. 

 Some protozoa (Myxosporida and Microsporida) 

 can infect muscle or skin tissue and multiply to 

 produce gross cysts. These infections mature to 

 produce many characteristic microscopic spores, 

 and in the process the overlying epidermis may be 

 sloughed, producing ulcers with usually smooth 

 borders (Figure 4). However, it seems to be a 



Figure 3. — Ulcers and fin erosion in summer flounder produced by experimental inoculation oiVibrio sp. (Photograph courtesy of 

 R. Robohm, Northea.st Fisheries Center Milford Laboratory, NMFS, NOAA, Milford, Conn.) 



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