494 
Fishery Bulletin 96(3), 1998 
Table 1 
Number of fish-impingement samples taken during normal operations at four coastal electrical power generating stations from 
1977 to 93. 
Year 
Huntington Beach 
Ormond 
Redondo (units 7-8) 
San Onofre 1 
San Onofre 2 
San Onofre 3 
1977 
0 
0 
87 
76 
0 
0 
1978 
13 
13 
67 
90 
0 
0 
1979 
55 
68 
73 
93 
0 
0 
1980 
98 
100 
103 
34 
0 
0 
1981 
60 
58 
52 
42 
0 
0 
1982 
47 
43 
35 
19 
27 
0 
1983 
57 
55 
48 
23 
61 
8 
1984 
57 
50 
58 
28 
65 
70 
1985 
56 
54 
55 
63 
84 
67 
1986 
53 
57 
49 
28 
69 
101 
1987 
45 
57 
43 
51 
57 
60 
1988 
41 
47 
25 
42 
57 
47 
1989 
38 
46 
47 
40 
46 
58 
1990 
26 
37 
30 
36 
55 
43 
1991 
16 
43 
50 
48 
46 
57 
1992 
37 
44 
38 
58 
78 
68 
1993 
67 
40 
31 
24 
65 
69 
Total 
753 
799 
737 
629 
710 
648 
All data presented were obtained during “normal” 
power plant operations. During normal operation, 
fishes are entrained in the cooling water and flow 
through conduits to the station where they are im- 
pinged on traveling screens in the forebay of the 
power plant. “Normal” fish-impingement surveys 
consist of counting all fishes impinged during a 24-h 
period of routine plant operations (e.g. on full flow 
days). Impinged fishes are separated from inciden- 
tal debris, sorted by species, identified, counted, and 
measured to standard length (mm). 
Because flow rates differed slightly among stations 
and years, all abundance data are presented as the 
number of fishes per million gallons of water pass- 
ing through the intake. Flow rates also varied within 
each station from month to month but remained con- 
stant during any given month. Thus, it was neces- 
sary to calculate monthly mean catch rates for each 
site. Annual mean catch rates are presented in this 
paper. For most analyses, annual catch is the grand 
mean of all monthly means across all sites for that 
year. For one comparison, mean annual catch rates 
are calculated for the Redondo station only. 
Results 
During this survey, 27,546 rockfishes, representing 
16 identifiable species, were caught (Table 2). Olive 
rockfish ( Sebastes serranoides) were the most com- 
Table 2 
Number of rockfish impinged during normal operations at 
four coastal electrical power generating stations from 1977 
to 93. 
Species 
Common name 
Number 
Sebastes serranoides 
Olive rockfish 
14,571 
S. auriculatus 
Brown rockfish 
5586 
S. paucispinis 
Bocaccio 
3262 
S. mystinus 
Blue rockfish 
1640 
S. serriceps 
Treefish 
1124 
S. rastrelliger 
Grass rockfish 
1092 
Sebastes spp. 
Unidentified rockfish 
129 
S. carnatus 
Gopher rockfish 
65 
S. dalli 
Calico rockfish 
44 
S. caurinus 
Copper rockfish 
9 
S. miniatus 
Vermilion rockfish 
8 
S. atrovirens 
Kelp rockfish 
8 
S. goodei 
Chilipepper 
5 
S. melanops 
Black rockfish 
2 
S. oval is 
Speckled rockfish 
1 
S. maliger 
Quillback rockfish 
1 
S. flavidus 
Yellowtail rockfish 
1 
Total rockfish 
27,546 
monly taken, followed by brown rockfish {S. auricu- 
latus ), bocaccio ( S . paucispinis), blue rockfish {S. 
mystinus), treefish (S. serriceps ), and grass rockfish 
{S. rastrelliger). These six most abundant species 
represented 99% of all rockfish caught. From the 
lengths of the fishes sampled (Fig. 2), we determined 
