FISHERY BULLETIN: VOL. 83, NO. 2 



Flatfish (Pleuronectidae, Bothidae, and Cynoglos- 

 sidae) and rockfish (Scorpaenidae) accounted for 

 65.5% of the affected species and 99.2% of the 

 affected individuals; Dover sole (Pleuronectidae) 

 accounted for 88.9% of the affected individuals. 



The number of species affected by fin erosion 

 declined from a high of 18 in 1971 to a low of 3 in 

 1981 (Fig. 2); the decrease w^as highly significant 

 (r = -0.766, n = 12, 0.002 <P < 0.005). There 

 was no significant change in the number of species 

 collected over the same period (Fig. 2) (r = -0.291, 

 n = 12, 0.20 <P < 0.50). 



80-1 



TOTAL 



" YEAR ^« 



82 



Figure 2. — Annual total number offish species collected and 

 number with fin erosion collected by otter trawl on the Palos 

 Verdes shelf from 1971 to 1982. 



but the increase was not significant at TO (Table 

 2). ANCOVA detected a significant difference 

 among the regression coefficients of the 61 m sta- 

 tions (F = 5.02, 0.003 <P < 0.005) (Table 3). 



The total number of calico rockfish collected in a 

 10-min trawl at 61 m decreased significantly at T4, 

 but did not change at TO, Tl, and T5 (Table 2). The 

 regression coefficients for these collections were 

 not significantly different (F = 1.02, P > 0.25). 



REX SOLE 



Seven percent of the rex sole, Glyptocephalus 

 zachirus, had fin erosion; as a species, they ac- 

 counted for 2% of all fish with the disease (Table 1). 

 More than 99% of the rex sole collected were 

 caught at 137 m. Less than 1% of the fish collected 

 at station TO-137 m had fin erosion. The incidence 

 of fin erosion among rex sole at the remaining 

 137 m stations declined significantly (Table 4). 

 ANCOVA did not detect a significant difference 

 among the regression coefficients for these collec- 

 tions (F = L05,P > 0.25). 



The number of rex sole caught in a 10-min trawl 

 at the 137 m stations did not change over the study 

 period (Table 4), and the regression coefficients for 

 these collections were not significantly different 

 (F = 1.43, 0.10 <P< 0.25). 



CALICO ROCKFISH 



DOVER SOLE 



Calico rockfish, Sebastes dallii, were rarely col- 

 lected before 1975. Beginning in 1975, they were 

 collected at all stations; the majority (72.4% ) were 

 collected at 61 m. Ten percent of the individuals 

 collected had fin erosion; as a species, they ac- 

 counted for 6% of all fish with the disease (Table 1). 

 The incidence of fin erosion among calico rockfish 

 increased at all 61 m stations from 1975 to 1982, 



Dover sole. Microstomas pacificus, was by far 

 the most affected species. Thirty-four percent of 

 Dover sole collected had fin erosion; as a species, 

 they accounted for 89% of all fish with the disease 

 (Table 1). The incidence of fin erosion among Dover 

 sole declined significantly at all stations except 

 TO-137 m (Table 5). ANCOVA detected a signifi- 

 cant difference among the regression coefficients 



Table 2. — Linear regressions of A) the proportion (p) of calico rockfish, 

 Sebastes dallii, in one 10-min trawl with fin erosion (transformed to arcsin 

 \ p) and B) the total number of calico rockfish caught in one 10-min trawl 

 [transformed to logio ^x + 1)\ against time (numbered in consecutive 

 months from 1971 through 1982). n = sample size; LI = lower limit of 95% 

 confidence interval of the regression coefficient ib); L2 = upper limit; 

 P = probability that b came from a sampling population with fi = 0. 



198 



