468 
Fishery Bulletin 96(3), 1 998 
used for stock assessments is M = 0.10 or less (Methot 
et al., 1994). Thus fish tagged in the early 1970s were 
still contributing to recoveries as of 1993 (Table 5). 
It is also notable that sablefish tagged offshore are 
usually not recaptured immediately; recoveries are 
typically protracted over many years. 
Results related to population structure 
Mapping the location of the 14,903 sablefish tag recov- 
eries shows a geographic continuity in sablefish distri- 
bution and commercial fishing effort (Fig. 2). The few 
offshore recoveries in midocean were located on sea- 
mounts. If we plot the source of these seamount recov- 
eries (Fig. 3), we see that they came from virtually all 
areas of release (see Shaw and Parks, 1997, for details). 
Table 6 lists the area of release against the area of 
recovery for the 27 areas in Figure 1. The data show 
that sablefish tagged off Alaska north of 50°N lati- 
tude have a 96.5% chance of being recaptured north 
of 50°N. Similarly, sablefish tagged off the west coast 
south of 50°N latitude have a 95.6% chance of being 
recovered south of 50°N. 
Table 6 suggests that Alaska sablefish mix in ar- 
eas 1-19. It is noteworthy that all Alaska areas show 
reciprocal migrations to all other Alaska areas. Mix- 
ing is also suggested from the fact that the recovery 
rate for fish tagged in all these areas is similar (Table 
4). In contrast, west coast sablefish (areas 20-27) 
largely confined their movements within the area of 
release (64.4% of west coast tag recoveries came from 
the same areas as their release compared with 35.8% 
for Alaska). 
Tag recoveries indicate that Alaska sablefish on 
average move considerably further than west coast 
sablefish (Fig. 4). More than 30% of tagged Alaska 
Table 4 
Table showing the percentage of tags recovered from releases in each area. Also shown by size category are the percentage of 
tagged fish moving north or west, staying put, and moving east or south. Areas are described in Table 2 and Figure 1. 
Size less than 57 cm Size greater than 57 cm 
All sizes 
Percent 
Percent 
Percent 
Percent 
Percent 
Percent 
Percent 
north or 
in area of 
east or 
north or 
in area of 
east or 
Area 
recovered 
west 
tagging 
south 
west 
tagging 
south 
1 
2 
3 
5.4 
0.0 
11.8 
88.2 
0.0 
2.2 
97.8 
4 
6.3 
0.0 
24.4 
75.6 
0.4 
13.0 
86.6 
5 
n 
6.2 
2.4 
32.7 
64.9 
1.8 
20.9 
77.3 
D 
7 
3.8 
0.0 
0.0 
100.0 
0.0 
29.2 
70.8 
8 
5.3 
0.0 
28.6 
71.4 
2.9 
28.3 
68.8 
9 
5.5 
9.1 
30.5 
60.4 
4.1 
26.8 
69.1 
10 
5.8 
20.0 
16.5 
63.5 
10.6 
18.5 
70.9 
11 
6.1 
26.6 
21.3 
52.1 
4.8 
15.6 
79.6 
12 
6.8 
17.4 
31.3 
51.4 
10.5 
18.8 
70.7 
13 
5.8 
19.3 
27.4 
53.3 
10.9 
17.9 
71.2 
14 
5.4 
20.5 
36.6 
42.9 
9.8 
29.2 
61.1 
15 
4.9 
34.9 
29.5 
35.7 
15.2 
43.4 
41.5 
16 
4.9 
46.4 
34.0 
19.6 
25.9 
42.8 
31.3 
17 
6.3 
41.9 
36.7 
21.3 
24.2 
56.8 
19.0 
18 
19 
20 
7.9 
40.9 
42.7 
16.4 
29.2 
59.3 
11.6 
8.0 
10.7 
74.5 
14.8 
6.4 
76.0 
17.6 
21 
7.6 
22.5 
66.6 
10.9 
19.5 
71.4 
9.1 
22 
6.0 
16.1 
73.6 
10.4 
18.3 
70.7 
11.0 
23 
14.8 
17.6 
64.9 
17.5 
18.9 
67.1 
14.0 
24 
8.4 
31.5 
61.9 
6.6 
38.7 
55.5 
5.9 
25 
9.1 
41.3 
54.3 
4.5 
32.9 
64.4 
2.7 
26 
8.8 
44.6 
54.4 
0.9 
53.6 
46.4 
0.0 
27 
6.7 
36.3 
63.7 
0.0 
57.7 
42.3 
0.0 
