FISHERY BULLETIN: VOL. 75, NO. 3 



median level of total DDT in muscle tissue from 

 Dover sole collected off Palos Verdes was about 

 10 times greater than the median level observed 

 for the Orange County specimens (McDermott 

 and Heesen 7 ). 



These results support the hypothesis that the 

 Dover sole with fin erosion collected off Orange 

 County came from the Palos Verdes population. 

 They also suggest that levels of DDT in tissues 

 may be used as a tag when investigating local 

 migrations of fish from or across a known point 

 source of DDT. 



There were no significant differences (P>0.20) 

 between the total PCB levels in unaffected Dover 

 sole from Orange County and Palos Verdes, nor 

 between the total PCB levels in diseased fish from 

 the two areas. The overall median total PCB con- 

 centrations in muscle tissue of unaffected fish 

 from Orange County and Palos Verdes were 0.6 

 and 1.2 mg/kg wet weight, respectively; from dis- 

 eased specimens, 2.3 and 2.1 mg/kg wet weight, 

 respectively. 



Association of Chlorinated Hydrocarbons 

 with Fin Erosion 



Since the diseased fish at Orange County appear 

 to have originated from Palos Verdes and the 

 Palos Verdes area is the primary site of total DDT 

 and total PCB sediment contamination, only the 

 results obtained for total chlorinated hydrocarbon 

 measurements in diseased and unaffected Dover 

 sole collected from Palos Verdes were utilized to 

 test for the association of chlorinated hydro- 

 carbons with fin erosion. Using the Mann- 

 Whitney 17-test we found that the DDT levels in 

 diseased Palos Verdes Dover sole were signifi- 

 cantly greater (P<0.05) than the DDT levels 

 measured in unaffected Palos Verdes specimens. 

 The overall median values for diseased and un- 

 affected Dover sole were 18 and 11 mg/kg wet 

 weight, respectively. 



Differences in the levels of total PCB in the 

 muscle tissue of diseased and unaffected Dover 

 sole were significant only at the 90% confidence 

 level (P<0.10). Thus there was a tendency for 

 the total PCB levels to be higher in the diseased 



fish. The median values for the diseased and un- 

 affected groups were 2.1 and 1.2 mg/kg wet 

 weight, respectively. 



These results indicate that there is a significant 

 association between high levels of total DDT and 

 fin erosion, and a possible association between 

 high levels of total PCB and fin erosion in Dover 

 sole collected off Palos Verdes. 



There are several possible reasons for these 

 associations. DDT and PCB in combination with 

 each other and/or other constituents present in 

 this region (such as hydrogen sulfide, high levels 

 of trace metals, or abrasive materials) could be 

 involved in the development of the disease. Alter- 

 natively, chlorinated hydrocarbon uptake could 

 be enhanced in diseased fish; hence the higher 

 levels might be the result of the disease rather 

 than a cause. A third possibility is that the fish 

 with fin erosion have been present on the Palos 

 Verdes shelf longer than the unaffected fish and 

 have been exposed to the chlorinated hydro- 

 carbons for a longer period of time. These possible 

 explanations are presently under investigation. 



It is interesting to note that while the Palos 

 Verdes municipal wastewater discharges of DDT 

 significantly decreased from greater than 20 

 metric tons in 1971 to 2 metric tons in 1974 

 (Young et al. 1975), the levels of DDT in the Dover 

 sole have remained unchanged (McDermott and 

 Heesen see footnote 7). Similarly, the level of DDT 

 in the surface sediments off the Palos Verdes 

 Peninsula remained relatively constant over the 

 3-yr period, 1971-73 (Young et al. 1975; Young et 

 al. 1976b). The situation for PCB is similar. The 

 discharge of PCB decreased from greater than 

 19 metric tons in 1972 to 5 metric tons in 1974 

 (Young et al. 1976a) and the levels of PCB in the 

 Dover sole remained unchanged (McDermott et 

 al. 1976). Unfortunately, reliable historical data 

 for PCB's in the Palos Verdes surface sediments 

 are not available. The overall prevalence of fin 

 erosion in Dover sole also remained relatively 

 constant over the same time period (Sherwood 

 and Mearns 8 ). These findings point to the poten- 

 tially significant role that the sediments may 

 have in the uptake of chlorinated hydrocarbons 

 and in the development of fin erosion in Dover 

 sole. 



'McDermott, D. J., and T. C. Heesen. 1975. DDT and PCB 

 in Dover sole around outfalls. In Coastal water research project 

 annual report, p. 117-121. South. Calif. Coastal Water Res. 

 Proj., El Segundo. 



"Sherwood, M. J., and A. J. Mearns. 1975. Sampling diseased 

 fish populations. In Coastal water research project annual 

 report, p. 27-32. South. Calif. Coastal Water Res. Proj., El 

 Segundo. 



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