366 
Fishery Bulletin 1 10(3) 
Table 2 
Growth parameters (L oo = average maximum length, r=mean growth coefficient, t 0 =mean theoretical age a fish would have been 
at zero length) for female sablefish (Anoplopoma fimbria) in Alaska estimated with the von Bertalanffy model fitted to age-length 
data stratified by region and time period, where n is the number of age-length observations and an asterisk (*) indicates a signifi- 
cant difference between the 2 survey periods, 1981-93 and 1996-2004, for that particular region. Standard errors of the mean 
(SE) are presented in parentheses. RSS=residual sum of squares. 
Region 
Survey period 
k 
*0 
RSS 
n 
All regions combined 
1981-93 
75.0 (0.35) 
0.263 (0.01) 
-2.00 (0.29) 
3945 
4788 
1996-2004* 
80.1* (0.26) 
0.223 (0.01) 
-1.92 (0.14) 
1191 
3493 
1981-2004 
77.1 (0.77) 
0.25(0.02) 
-1.91 (0.32) 
23,963 
8281 
Chirikof 
1981-93 
75.3 (1.29) 
0.298 (0.04) 
-0.798 (0.58) 
1275 
165 
1996-2004 
77.5 (0.51) 
0.294 (0.02) 
-0.802 (0.40) 
609 
485 
1981-2004 
76.8 (0.56) 
0.302 (0.02) 
-0.697 (0.33) 
2201 
650 
Aleutian 
1981-93 
73.8 (0.84) 
0.197 (0.04) 
-3.888 (1.30) 
4839 
1037 
1996-2004* 
77.9* (1.31) 
0.218 (0.03) 
-2.246 (0.69) 
2191 
795 
1981-2004 
73.8 (0.69) 
0.248 (0.03) 
-2.210 (0.70) 
9466 
1832 
Kodiak 
1981-93 
74.5 (0.84) 
0.305 (0.04) 
-1.288 (0.51) 
3334 
831 
1996-2004* 
78.6* (0.50) 
0.311 (0.03) 
-0.49 (0.42) 
1081 
602 
1981-2004 
76.7 (0.63) 
0.292 (0.03) 
-1.220 (0.40) 
7231 
1433 
Shumagin 
1981-93 
73.2 (0.69) 
0.295 (0.03) 
-1.724 (0.58) 
1993 
975 
1996-2004* 
81.6* (1.30) 
0.177* (0.02) 
-3.046 (0.49) 
877 
563 
1981-2004 
74.7 (0.72) 
0.256 (0.02) 
-2.028 (0.48) 
4830 
1538 
Bering 
1981-93 
68.3 (0.59) 
0.351 (0.05) 
-1.79(0.76) 
1925 
993 
1996-2004* 
76.4* (0.87) 
0.223* (0.02) 
-2.746 (0.62) 
695 
533 
1981-2004 
70.2 (0.74) 
0.306 (0.05) 
-2.163 (0.82) 
6979 
1526 
Southeast 
1981-93 
78.3 (1.02) 
0.189 (0.03) 
-3.579(0.95) 
4488 
787 
1996-2004* 
80.8* (0.50) 
0.273* (0.02) 
-0.816* (0.42) 
964 
515 
1981-2004 
79.3 (0.72) 
0.217 (0.02) 
-2.489 (0.61) 
8949 
1302 
Table 3 
Comparison of 4 age-length models used for analyses of regional and temporal effects on growth of male sablefish ( Anoplopoma 
fimbria) in Alaska. The most reasonable model, indicated with an asterisk (*), is the reduced model with a residual sum of squares 
(RSS) not significantly greater than the RSS for the full model. rc = the number of observations, and £ 2 =the chi-squared value. 
Model 
RSS 
t 
P 
No. of parameters 
n 
Data split by each combination of region and survey period * 
11,729 
36 
Data split into 2 survey periods 
16,354 
114.7 
<0.001 
6 
Data split into 6 regions 
18,449 
156.3 
<0.001 
18 
All data pooled 
21,642 
211.3 
<0.001 
3 
6043 
estimates (PcO.OOl) and the growth curves were sig- 
nificantly different (P<0.001; Table 2) between the 2 
periods. 
A comparison of male growth curves between the 2 
survey periods, stratified by region, showed a consis- 
tent pattern of slower growth and smaller asymptotic 
lengths during the earlier survey period. There were 
significant differences between growth curves fitted to 
the 2 periods in 5 of the 6 management regions (Fig. 3, 
Table 1). Fish from most regions had a smaller asymp- 
totic length and slower growth during the earlier survey 
period than during the more recent period. In contrast, 
during the earlier survey period versus the more recent 
one, males in the Shumagin region reached a smaller 
maximum length but grew faster and males in the 
Chirikof region displayed a larger asymptotic length 
and grew more slowly. 
Age-length relationships for females between the 2 
survey periods differed significantly in 5 of the 6 man- 
agement regions (Fig. 4, Table 2). Female asymptotic 
