CHLORINATED HYDROCARBONS IN DOVER SOLE, 

 MICROSTOMUS PACIFICUS: LOCAL MIGRATIONS AND FIN EROSION 



D. J. McDermott-Ehrlich, 1 M. J. Sherwood, 2 T. C. Heesen, 2 D. R. Young, 2 and A. J. Mearns 2 



ABSTRACT 



Dover sole, Microstomas pacificus, with and without fin erosion were collected from the municipal 

 wastewater discharge sites of Los Angeles and Orange counties. While there was a significant differ- 

 ence between the total DDT levels in muscle tissue of the unaffected fish from the two regions, there 

 was no significant regional difference between the muscle DDT levels in the diseased fish. This is 

 consistent with the proposed hypothesis that the Orange County diseased fish had originated at the 

 Los Angeles County discharge site. Comparisons of chlorinated hydrocarbon levels in diseased and 

 unaffected Dover sole from the Palos Verdes discharge site of Los Angeles County indicate: 1 ) DDT 

 levels were significantly higher (P<0.05) in Dover sole with fin erosion, and 2) polychlorinated 

 biphenyl levels were higher at the 90% confidence level (P<0.10) in diseased Dover sole. 



In recent years, fin erosion diseases have been 

 observed in several species of marine fishes col- 

 lected from areas contaminated by industrial or 

 municipal waste such as the Duwamish River es- 

 tuary, Wash. ( Wellings et al. 1976), the New York 

 Bight (Mahoney et al. 1973; Murchelano 1975), 

 and major municipal wastewater discharge sites 

 in the Southern California Bight (Mearns and 

 Sherwood 1974). In southern California, the dis- 

 ease is most prevalent in the Dover sole, Micro- 

 stomas pacificus Lockington, a marine flatfish. 



Dover sole with fin erosion occur most fre- 

 quently near the Palos Verdes discharge site of 

 the Joint Water Pollution Control Plant ( JWPCP) 

 submarine outfalls of the County Sanitation Dis- 

 tricts of Los Angeles County. During the period 

 1972-76, 39% of the 20,854 Dover sole collected 

 in 268 samples off Palos Verdes had fin erosion. 

 Only 3.5% of 894 individuals collected in Santa 

 Monica Bay to the north (109 samples), 2.0% of 

 5,354 individuals collected in south San Pedro 

 Bay to the south (138 samples), and 0.67% of 889 

 individuals collected off Dana Point farther south 

 (77 samples) were affected with the disease. 



The JWPCP outfalls are the dominant source of 

 DDT residues (total DDT) and most trace metals 

 introduced via municipal wastewaters to the 

 Southern California Bight (Galloway 1972; 

 Young et al. 1973; Young et al. 1976b). Although 



'Southern California Coastal Water Research Project; present 

 address: Lockheed Center for Marine Research, P.O. Box 398, 

 Avila, CA 93424. 



2 Southern California Coastal Water Research Project, 1500 

 East Imperial Highway, El Segundo, CA 90245. 



in 1974 Orange County's discharge of poly- 

 chlorinated biphenyl (PCB) was twice that of any 

 other discharger (Young et al. 1976a), the sedi- 

 ments off the Palos Verdes Peninsula, as a result 

 of past discharges, have the highest levels of total 

 PCB and total DDT found in marine sediments of 

 the Bight (Young et al. 1976a, b). 



The Dover sole is one of the most abundant 

 and most frequently encountered species in trawl 

 catches taken in the vicinity of the southern Cal- 

 ifornia submarine municipal wastewater outfalls 

 (Southern California Coastal Water Research 

 Project 1973). In southern California, as in north- 

 ern California where it is the focus of a major 

 bottom fishery (Hagerman 1952), Dover sole 

 undergo seasonal onshore-offshore migrations 

 (Mearns and Sherwood 1974). Individuals move 

 offshore in the winter and onshore in the summer 

 and have been collected off southern California at 

 depths generally greater than 25 m. 



In May and August 1972, trawl catches taken 

 in the vicinity of the Orange County outfall sys- 

 tem in south San Pedro Bay contained higher 

 numbers of Dover sole with fin erosion than did 

 previous catches (6 of 684 individuals and 34 of 

 611 individuals, respectively). This increase was 

 associated with a large influx of Dover sole into 

 the area. Only 273 individuals had been collected 

 in February 1972. Orange County trawls were 

 taken at a standard set of eight stations with the 

 same gear and vessel combination. Only larger 

 individuals (generally >120 mm standard length, 

 SL) were affected with the disease; this contrasted 

 with the situation off Palos Verdes, where Dover 



Manuscript accepted February 1977. 

 Fishery Bulletin: VOL. 75, NO. 3, 1977. 



513 



