444 
Fishery Bulletin 107(4) 
multiple regression analysis, wild abundance and date 
significantly affected condition factor in the inner inlet 
in 2005, and hatchery abundance had no significant 
effect. 
Habitat type and inlet location 
Figure 9 
Fork length (mm) of chum salmon ( Oncorhynchus keta ) 
fry in Taku Inlet, Alaska, during the outmigration 
period for wild fry (late April to mid- June), by loca- 
tion and habitat in (A) 2004 and (B) 2005. Sample size 
for early hatchery fry in neritic habitat in the inner 
inlet in 2005 was too small to be included in analysis. 
No late hatchery fish were caught in the inner inlet 
during either year. Vertical bars represent standard 
error about the mean. 
Condition factor of wild fry in the outer inlet was 
positively correlated with wild fry abundance but not 
with hatchery fry abundance in 2004 (Table 3). In the 
multiple regression analysis, wild fry abundance had 
a significant and positive effect on condition factor. 
Date also had a significant and positive effect, whereas 
salinity had a negative effect. Abundance of hatchery 
fry was not significant in the model in 2004. In 2005, 
condition factor of wild fry was not correlated with 
wild fry abundance but was positively correlated with 
hatchery fry abundance. In the multiple regression, 
hatchery fry abundance had a significant positive effect 
on condition factor, whereas wild fry abundance had a 
significant negative effect when included in the model 
with hatchery fry abundance (Table 3). 
Discussion 
The objectives for this study were 1) to determine the 
abundance and spatial and temporal overlap of wild 
chum salmon fry and hatchery chum salmon fry sub- 
jected to early and late rearing strategies in different 
habitats of Taku Inlet; 2) to compare the body size and 
condition of these groups of fry; and 3) to document 
environmental factors that potentially could explain the 
distribution, size, and abundance of fry. The ultimate 
goal for this study was to evaluate the potential for 
interactions between wild and hatchery chum salmon 
in Taku Inlet. Our results indicated that the greatest 
spatial and temporal overlap between wild and hatch- 
ery chum salmon fry occurred between wild and early 
hatchery fry in littoral and neritic habitats of the outer 
inlet. Both wild and early hatchery salmon were cap- 
tured together in the same habitats in Taku Inlet for up 
to four weeks. Hatchery production corresponded with a 
20-fold increase in overall abundance of chum salmon fry 
in the outer inlet, indicating a substantially increased 
likelihood of density-dependent interactions at this time 
(Simenstad et al., 1982; Levings et al., 1986; Willette, 
Table t 
Relationships of wild chum salmon ( Oncorhynchus keta) fry abundance to environmental factors and to hatchery chum salmon 
fry abundance from beach-seine collections in littoral habitat by inner and outer location in Taku Inlet, Alaska, during the 
outmigration period for wild fry (late April to mid-June), 2004-05, determined with stepwise multiple regressions (Eq. 1) and 
correlation analyses. SST = sea surface temperature; NS = not significant. 
Bivariate correlations with wild fry abundance 
Significance of regression parameters 
Inner 
Outer 
Inner Outer 
r P 
r P 
2004 
hatchery abundance 
Positive P<0.01 
Positive P<0.01 
0.365 
<0.01 
0.645 
<0.01 
SST 
NS 
NS 
0.198 
0.110 
0.027 
0.865 
salinity 
NS 
NS 
-0.246 
0.047 
0.099 
0.526 
2005 
hatchery abundance 
NS 
Positive P<0.01 
0.097 
0.460 
0.626 
<0.01 
SST 
NS 
NS 
-0.314 
0.025 
-0.200 
0.205 
salinity 
NS 
NS 
0.272 
0.035 
0.056 
0.695 
