FISHERY BULLETIN: VOL. 83, NO. 2 



Survival Rates 



The survival rates of Dover sole with and with- 

 out fin erosion from Paios Verdes were not signifi- 

 cantly different from age 1 to age 2 {t ^ 1.267, df 

 = 4, 0.10 < P < 0.25) and from age 2 to age 3 

 {t - 0.741, df = 4,P = 0.25) (Fig. 6). The survival 

 rates were significantly lower for individuals with 

 fin erosion from age 3 to age 4 (^ = 2.826, df = 4, 

 0.01 <P < 0.025) and from age 4 to age 5 

 (t = 2.890, df= 4,0.01 <P < 0.025). No individu- 

 als with fin erosion older than age 5 were collected 

 (Fig. 6). 



FIGURE 6. — Survival rate of Dover sole, Microstomas 

 pacificus, with fin erosion (solid line) and without fin erosion 

 (dashed line) from year t to year t + 1. Data presented as mean 

 and 1 SE (vertical line). 



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OUTFALLS 



Figure 7. — Contour maps of total DDT (ppm dry weight) and 

 copper (ppm dry weight) concentrations in surface sediments 

 on the Palos Verdes shelf in 1975. Maps redrawn from Her- 

 shelmanet al. (1977). 



DISCUSSION 



Current and Sediment Characteristics 

 on the Palos Verdes Shelf 



Near the outfalls, the net current movement 20 

 m from the bottom in 61 m of water is 5.5 cm/s 

 upcoast (northwest). Both net flow and major 

 current fluctuations are oriented in the upcoast 

 direction (Hendricks 1980). Sewage particles sus- 

 pended in freshwater are discharged from the out- 

 falls, rise in the water column, and are carried 

 generally upcoast as they settle back to the bot- 

 tom. Trace metal and chlorinated hydrocarbon 

 contaminants measured in surface sediments re- 

 veal the characteristic "footprint" of the settled 

 particles (Fig. 7) (Young and Heesen 1978; Young 

 et al. 1978). The concentrations of DDT (Table 9), 

 trace metals (Table 10), and organic material (Ta- 

 ble 11 ) in surface sediments are highest around the 

 outfalls and decline upcoast, and generally have 

 declined during the study period. 



Table 9. — Total DDT concentration (ppm dry weight) of surface 

 sediments at the sampling transects from 1972 to 1981. Note that 

 the deeper samples were taken at 152 m while the trawls were 

 made at 137 m. Depth of sediments analyzed at bottom of the 

 table. (SCCWRP and LACSD, unpubl. data.) 



Spatial Disease Patterns 



Of the three depths sampled (23, 61, and 137 m), 

 <1% of the fish with fin erosion were collected at 

 23 m. This is probably a function of low sediment 

 contamination at the shallowest stations (Table 9). 

 Coastal sediments in southern California are 



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