494 
Fishery Bulletin 107(4) 
was significantly higher (P<0.05) during the 1922-46 
warm regime than during the 1947-76 cool, and 1977- 
2000 warm regimes. Mean M3 was significantly higher 
(25%; Dunn’s test, nonparametric test; P<0.05) during 
the 1947-76 cool regime than during the 1922-46 warm 
regime but not significantly higher (P>0.05) than the 
mean M3 during the 1977-2000 warm regime. Growth 
variables within a brood were not significantly corre- 
lated (Table 2). 
The regional C-0 indices in the North Pacific varied 
in association with the warm (1922-46), cool (1947-76), 
and warm (1977-2000) C-0 regimes (Fig. 3). Compared 
to the 1947-76 cool regime, the 1977-2000 warm regime 
had 1°C higher SST, a 54% higher PREC, weaker coast- 
al downwelling near Prince William Sound, 42% higher 
AFI, and 61% lower NOI. Compared to the 1947-76 cool 
regime, the 1922-46 warm regime had a 27% higher 
PREC and a 47% higher AFI. 
Influence of regional C-O conditions 
on mean sockeye salmon growth 
Regional C-0 indices correlated significantly with juve- 
nile (Ml) and immature (M2) scale growth, but not with 
maturing growth (M3) (Table 3). Growth was correlated 
with C-0 indices for the 1951-2000 period, but not with 
C-0 indices for the 1922-2000 period. Growth indices 
were correlated with two of the five C-0 indices. Ml 
had a significant positive association with AFI (r=0.40; 
P= 0.005). M2 had a strong positive relationship with the 
PREC (r=0.39; P=0.005). FW and M3 did not correlate 
with the five C-0 indices. 
Interrelationships among regional C-O conditions, 
mean growth, and annual survival of sockeye salmon 
Survival, as indicated by the residuals from the stock- 
recruitment model, was higher than expected during 
warm regimes and lower than expected during the cool 
regime (Fig. 4), and there was a brief high from 1959 
to 1965. The linear regression model of the logarithm 
of the recruits per spawner [ln(P/P)J as a function of 
spawners (E) was 
In (R t+r / E , ) = -0.48039 x 10 7 -E + 0.7668. (3) 
A reduction in the number of recruits per escapement 
at higher escapement levels is characteristic of strong 
density-dependence at high stock levels (r 2 - 0.1035; 
P=0007). Residuals of the model were used as an index 
for survival. 
Survival was not significantly correlated with growth 
(Table 4), but it was significantly correlated with four 
of the five C-0 indices and with C-0 indices during all 
marine life stages (Table 5). For the 1921-89 broods, 
survival was correlated positively with SST (0.409, 
0.567, 0.536) and AFI (0.314, 0.307, 0.364) during the 
Ml, M2, and M3 years spent at sea by the age-2.2 fish 
in the brood (Table 5). For the 1948-89 brood years, 
survival correlated positively with SST (0.409, 0.607), 
Table 2 
Correlation coefficients (r) and P-values among growth 
variables for broods of age-2.2 sockeye ( Oncorhynchus 
nerka) that returned as adults to the Karluk River weir 
during the early run . Scales were used for measurements. 
Smolt length (freshwater, FW), and juvenile (first-year 
marine, Ml), immature (second-year marine, M2), and 
maturing (third-year marine, M3) growth were esti- 
mated from measurements of the scales of age-2.2 sock- 
eye salmon that returned to the Karluk system, Kodiak 
Island, Alaska. There were no significant relationships 
between any pair of variables in the correlation table at 
5% (P<0. 008 = 0. 05/6) and 1% (P<0.002 = 0.01/6). 
Brood Growth 
year variables Ml M2 M3 
1919-95 
n=71 
FW 
r 
-0.150 
-0.079 
-0.214 
p 
0.212 
0.512 
0.073 
Ml 
r 
0.24 
0.253 
p 
0.060 
0.033 
M2 
r 
0.009 
p 
0.940 
1948-95 
II 
OO 
FW 
r 
0.287 
0.055 
0.065 
p 
0.051 
0.722 
0.675 
Ml 
7' 
0.138 
-0.098 
P 
0.372 
0.527 
M2 
r 
-0.291 
p 
0.050 
PREC (0.397, 0.349), and AFI (0.447, 0.477) during the 
first and second year at sea. A significant negative cor- 
relation of 0.421 occurred between UI and survival in 
the final year at sea. 
Discussion 
Influence of C-O regimes 
on mean sockeye salmon growth 
The synchronous patterns between sockeye salmon 
mean Ml and M2 growth indices and the two most 
recent ocean regimes may indicate that changes in C-0 
conditions in the North Pacific Ocean influenced the 
marine growth of sockeye salmon from Karluk River 
and Karluk Lake. The increase in juvenile and imma- 
ture growth and the reduction of maturing growth 
in the final year at sea of sockeye salmon from the 
northern Gulf of Alaska after the 1976-77 regime 
shift is distinct from the growth pattern seen in sock- 
eye salmon stocks from the Bering Sea off western 
Alaska. For western Alaska, the Ml of Bristol Bay 
sockeye salmon and Ml and M2 of Chignik sockeye 
salmon tended to increase soon after the 1976-1977 
climate shift (Ruggerone et al. 2007). However, for 
