Love et al.: Declines in rockfish recruitment and populations 
497 
Olive rockfish 
Brown rockfish 
Figure 4 
Annual number of rockfishes impinged per million gallons of water pumped 
for the six most commonly impinged species, 1977-93. Note log scale. See 
text for description of the calculation of mean. Error bars are ±1 SE. 
It is likely that the decline in rock- 
fish abundance in the southern Califor- 
nia Bight was well underway by 1977 
when the current impingement surveys 
started. The King Harbor survey began 
in 1974 and results showed that the 
abundance of blue rockfish and bocac- 
cio were at much higher levels from 
1974 to 1977 than in later years. For 
example, blue rockfish were extremely 
abundant in King Harbor in 1974 but 
since 1983, not a single blue rockfish 
has been observed or impinged. There 
were also occasional impingement col- 
lections dating back to 1975 and these 
also indicate that pre-1977 rockfish 
catches were as high or higher than 
1977 levels. These pre-1977 impinge- 
ment surveys were too temporally 
sparse to be included in the complete 
data set, but they are suggestive. Thus, 
it appears that, despite larger variation 
in year to year rockfish impingement 
during the late 70s and early 80s, there 
has been an overall decrease since that 
time which probably reflects a decrease 
in nearshore populations of these spe- 
cies throughout the southern California 
Bight (Stephens 4 ; Love et al., in press). 
Although none of the previously men- 
tioned nearshore studies conducted dur- 
ing the 1950s-1970s were designed to 
focus on rockfish year-class strength, it 
appears from these surveys that the 
widespread abundance of nearshore 
rockfishes before the early 1980s was 
generated by a series of strong year 
classes. During this same period, South- 
ern California trawl studies of two other 
deeper-dwelling rockfish species im- 
plied a similar phenomenon (Mearns et 
al., 1980). It is likely that recent de- 
clines in abundance of these nearshore 
species were due to a decade-long se- 
ries of very poor year classes. 
What might be responsible for this 
poor rockfish recruitment? The succes- 
sion of poor year classes off southern 
California is likely linked to decade-long 
changes in oceanographic conditions. 
Most rockfishes are primatively vivipa- 
rous (Boehlert et al., 1987) and rockfish 
larvae are found primarily in the upper 
mixed layer (Ralston and Howard, 1995). After ap- 
proximately one month, rockfish larvae metamor- 
phose into pelagic juveniles that spend 3-6 months 
in the water column as plankton and micronekton 
