Boldt and Rooper: Abundance, condition, and diet of Sebastes alutus 
281 
0.08 -i A 
0.06 - 
0.04 - 
0.02 - 
0 
- 0.02 - 
- 0.04 - 
- 0.06 - 
- 0.08 - 
- 0.1 - 
-I— 
B N, June 
□ N, August 
□ S, August 
<160 
1— -r r ~^ ' 
<210 
>210 
6000 -| C 
S 
ct > 5000 
"co 
O 4000 
> 
o> 
o 
3000 
<160 <210 >210 
Size class (fork length in mm) 
Figure 3 
The average condition of three size classes (<160 mm, <210 
mm, and >210 mm fork length) of juvenile Pacific ocean perch 
( Sebastes alutus) collected with a bottom trawl at the north (N) 
and south (S) Samalga Island sites in August and at the N site 
in June. Condition is shown three ways: (A) log-transformed 
length-wet-weight residuals; (B) log-transformed length-dry- 
weight residuals; and (C) whole body energy content (calories 
per gram dry weight). Standard error bars are shown and 
asterisks indicate significant differences. 
fish: age 1 and 2 (small), 3 (medium), and 4 and 5 
years (large; D. H. Hanselman, Alaska Fisheries 
Science Center, personal communication). August 
sample sizes of small, medium, and large fish 
were 4, 4, and 43, respectively, at the north site, 
and 126, 93, and 67, respectively, at the south 
site. Only the large size class of juvenile POP was 
found in June at the north site (n = 34). 
Juvenile POP condition 
Generally, juvenile POP were in better condition 
at the north site than at the south site in August 
(Fig. 3). The linear regression of log wet weight 
as a function of log length was significant, as 
was the linear regression of log dry weight as a 
function of log length (P<0.001). There was no dif- 
ference in the dry weight expressed as a function 
of wet weight between the drying methods; there- 
fore, no correction factor was needed for drying 
technique. Both wet- and dry-weight residuals 
were higher at the north site for most size classes. 
Wet-weight residuals were significantly higher 
for both small and medium fish at the north site 
(P<0.05; Fig. 3). Dry-weight residuals were sig- 
nificantly higher for medium fish (P<0.001) and 
insignificantly higher for large fish (P= 0.686) at 
the north site (Fig. 3). Dry-weight residuals for 
small fish appeared to be lower for fish at the 
north site; however, the difference was not signifi- 
cant (P=0.156; Fig. 3). Because of small sample 
sizes of small and medium fish at the north site, 
variability in estimates were high and contributed 
to the opposing patterns of dry- and wet-weight 
residuals for small fish in the north. Large fish 
had similar wet- and dry-weight residuals at the 
two locations. Large fish sampled in June had 
significantly lower dry-weight residuals (P= 0.001) 
but similar wet-weight residuals (P=0.605) as 
those for large fish sampled in August at either 
site (Fig. 3). 
Energy content as estimated with a calorimeter 
provided more precise estimates of fish condi- 
tion (with lower variability) than length-weight 
residuals. Oven-drying resulted in a slightly 
lower energetic content than freeze drying ( 2 % 
difference in the means between the two meth- 
ods, SE = 0.002). A linear relationship (slope=1.31, 
intercept = -1363.86, r 2 = 0.964) predicting the 
freeze-dried energetic content from the oven-dried 
energetic content was applied as a correction fac- 
tor to the energetic value of the remaining oven- 
dried fish. Energy content varied significantly 
between the sites for all size classes (P<0.006), 
but not between sampling times (June and Au- 
gust; P=0.178) at the north site. Energy content 
of all size classes of fish was significantly higher at 
the north site than at the south site in August (Fig. 3). 
Energy content of individual juvenile POP ranged from 
3,463 to 5,569 cal/g dry weight. Small fish at the south 
site had the lowest average energy content (4,618 cal/g 
dry weight), whereas, the small and medium fish at 
the north site had the highest average energy content 
(5,295 and 5,213 cal/g dry weight, respectively). 
