Laidig: Influence of ocean conditions on the timing of early life events for Sebastes mystinus 
445 
settlement was 17 May 1993 for fish 
off Mendocino and 23 April (occurring 
in both 2001 and 1993) for fish from 
Monterey; the latest settlement date 
was 1 July 2002 for fish off Mendocino 
and 4 June 2002 for fish off Monterey. 
Settlement dates were later in 2002 
and 2003 and earlier in 1993 than in 
the other years. 
The duration of the larval and pe- 
lagic juvenile stages was not signifi- 
cantly different between the two areas 
in any particular year (Figs. 5 and 
6). The average duration for the lar- 
val stage was 69 days (range = 41-100 
d) for fish off Mendocino and 68 days 
(range = 47-90 d) for fish off Mon- 
terey. The average duration for the 
pelagic juvenile stage was 56 days 
(range=26-90 d) for fish off Mendoci- 
no and 52 days (range = 14-81 d) for 
fish off Monterey. Duration of pelagic 
larval and juvenile stages generally 
was longer for fish born in the 2000s 
than for fish born in the 1990s. Fish 
settled at younger ages at both study 
sites in the 1990s than in the 2000s 
(Fig. 7). Age at settlement was signifi- 
cantly different (P<0.05) between the 
two locations only in 2003; fish from 
Mendocino settled at an older age than 
those from Monterey. 
From the PCA, 56% of the variabili- 
ty in otolith data was explained by the 
first eigenvector for fish off Mendocino 
and Monterey. This vector was char- 
acterized by the inverse relationship 
of birth date and settlement age, i.e., 
the earlier the birth date, the older 
the settlement age. The second eigen- 
vector explained 41% and 39% of the 
variability in otolith data for fish off 
Mendocino and Monterey, respectively; 
this vector was characterized by later 
settlement dates and birth dates. The 
first eigenvector for oceanographic 
data explained 60% of the variability 
from Mendocino and 61% of the vari- 
ability in data from Monterey; this 
vector was associated with the inverse 
relationship of upwelling and sea level 
during the months of March through 
June off Mendocino and May and June 
off Monterey. The second eigenvector 
in the oceanographic data was related 
to the inverse relationship between 
upwelling and sea level in April at 
both sites and explained 30% and 28% 
of the variability in data from Men- 
docino and Monterey, respectively. 
ii 
March 
Q1 -j 
19 
February 
09 
20 
January 
♦ Mendocino 
■ Monterey 
1993 
1994 
# 
2001 
2002 
2003 
Year 
Figure 3 
Average birth dates (in calendar days), back-calculated from otolith data, 
for blue rockfish ( Sebastes mystinus) from two study areas in California. 
Black stars indicate significant differences (P<0.05) between study areas 
for a particular year. Dashed lines represent the 5-year average for each 
site. Vertical bars represent one standard error. Horizontal lines on the 
y axis separate months. 
29 i 
19 
♦ Mendocino 
■ Monterey 
June 
09 
30 
20 
May 
10 
* 
* 
★ 
* 
* 
1993 1994 
2001 
Year 
★ 
* 
★ 
* 
I 
2002 2003 
Figure 4 
Average settlement dates (in calendar days), back-calculated from oto- 
lith data, for blue rockfish (Sebastes mystinus ) from two study areas in 
California. Black stars indicate significant differences (PcO.001). Dashed 
lines represent the 5-year average for each site. Vertical bars represent 
one standard error. Horizontal lines on the y axis separate months. 
