SINDERMANN: POLLUTION-ASSOCIATED DISEASES AND ABNORMALITIES 



inherited subpopulation differences in one of the 

 three species studied. 



While the deformed gill rakers were the most 

 prevalent anomalies observed in southern 

 California barred sand bass by Valentine, other 

 abnormalities (pugheadedness, cranial asymme- 

 tries, deformed vertebrae, and fin anomalies) oc- 

 curred and were associated directly in frequency 

 and severity with gill raker deformity. 



An analysis of vertebral deformities in herring 

 taken in waters around the British Isles (van de 

 Kamp^") indicated a slight but significant increase 

 in prevalences from 1960 to 1975. The predom- 

 inant abnormality was a cluster of two or three 

 incomplete vertebrae located near the pelvic fins 

 or anus. The highest percentages of abnormalities 

 were found, according to the author, in areas 

 "which probably had the highest degree of pollu- 

 tion." It was in these areas where prevalences also 

 showed slight increases during the study period, 

 supporting the author's hypothesis that vertebral 

 deformities in herring can be related to "unusual 

 substances" in the environment. However, van de 

 Kamp concluded by stating that more experimen- 

 tal work on the causal relationship between pollu- 

 tion and deformities will be required. 



Several reports from Japan refer to high and 

 increasing occurrences of skeletal anomalies in 

 fish. Komada (1974) and Ueki and Sugiyama 

 ( 1976) observed increasing numbers of malformed 

 sweetfish or ayu, Plecoglossus altivelis, in rivers 

 and culture farms. Skeletal abnormalities in mul- 

 let and eight other species from the Inland Sea of 

 Japan were reported by Matsusato (1973). 



Deformed fin rays (Figure 8) and associated 

 skeletal abnormalities have been observed re- 

 peatedly in winter flounders from the highly pol- 

 luted waters of the New York Bight (Ziskowski et 

 al. in press), and a summarization of observations 

 on skeletal anomalies and related developmental 

 defects has been published recently (Sindermann 

 et al. 1978). 



There is some evidence from studies of a few 

 other fish species for an involvement of various 

 kinds of environmental stress in the occurrence 

 of skeletal anomalies. Gabriel (1944) noted 

 anomalies in vertebrae of Fundulus heteroclitus 

 due to temperature changes, and Mottley (1937) 

 found anomalies in vertebral numbers of trout due 



'"van de Kamp, G. 1977. Vertebral deformities in herring 

 around the British Isles and their usefulness for a pollution 

 monitoring programme. Int. Counc. Explor. Sea, Fish. Improv. 

 Comm.. Doc. CM1977 E:5, 9 p. 



to temperature (and possible oxygen). Hubbs 

 (1959) found high prevalences of vertebral abnor- 

 malities in mosquitofish, Gambusia affinis, from 

 Texas warm springs and concluded that the high 

 temperature was responsible. 



There is also an appreciable literature con- 

 cerned with induction of skeletal injuries in fish 

 by exposure to contaminants. Vertebral damage 

 following experimental exposure to aquatic con- 

 taminants has been reported for a number of 

 freshwater fishes (Bengtsson 1975). Long-term (10 

 wk) exposure of minnows {Phoxiniis phoxinus) to 

 sublethal concentrations of zinc and cadmium 

 resulted in hemorrhaging, spinal curvatures, 

 and vertebral fractures, particulary in the caudal 

 region, in up to 70^^ of individuals. Spinal curva- 

 tures and muscle atrophy were produced in rain- 

 bow trout by chronic exposure to lead. It is in- 

 teresting that caudal fin erosion was also observed 

 in these experiments. In earlier studies, sum- 

 marized by Bengtsson, exposure to sublethal con- 

 centrations of the chlorinated hydrocarbon Toxa- 

 phene as well as to Malathion, parathion, and 

 certain other organophosphorus pesticides pro- 

 duced vertebral damage or spinal flexures in sev- 

 eral fish species. Vertebral damage was consid- 

 ered to have a neuromuscular origin, or, in the 

 case of long-term exposure, to be a consequence of 

 demineralization. 



John Couch and associates at the Gulf Breeze 

 Environmental Research Laboratory of the U.S. 

 Environmental Protection Agency are developing 

 experimental evidence for induction of skeletal 

 abnormalities by exposure to environmental con- 

 taminants. Couch et al. (1977) reported severe 

 scoliosis and associated pathology in the sheeps- 

 head minnow, Cyprinodon variegatus, exposed to 

 the organochloride pesticide Kepone. The authors 

 concluded that scoliosis was a secondary effect of 

 Kepone toxicity, with the nervous system or cal- 

 cium metabolism as the primary target. 



Couch and associates (J. A. Couch, Research 

 Pathologist, Environmental Research Labora- 

 tory, U.S. Environmental Protection Agency, Gulf 

 Breeze, PL 32561. Pers. commun., June 1977) 

 have also found that trifluralin (Treflan) induced 

 extensive osseous hyperplasia in vertebrae of 

 sheepshead minnows when life history stages 

 from zygote to 28-day juveniles were exposed to 

 25-50 ppb trifluralin. Centra of vertebrae, thick- 

 ened by active osteoblasts and fibroblasts, in- 

 creased in size up to 10-30 times their normal 

 dimensions — a striking sublethal effect. 



733 



