Sogard and Berkeley: Movement, growth, and survival of Anoplopoma fimbria off Oregon 
235 
Table 1 
Releases of tagged sablefish {Anoplopoma fimbria) off Newport, Oregon, from February 1996 to May 1998 (tagging set 1), 
with gear used, depth of sampling (in meters), surface temperature, fish sizes (measured in fork length [FL]), number of fish 
tagged, and number of fish recaptured for each sampling trip. 
Trip (month/year) 
2/96 
3/96 
5/96 
6/96 
10/96 
9/97 
5/98 
Gear 
Trawl 
Trawl 
Trawl 
Trawl and pot 
Pot 
Trawl 
Trawl 
Depth range 
371-644 
431-565 
221-293 
141-631 
421-581 
227-649 
221-406 
(and mean) 
(460) 
(506) 
(240) 
(214) 
(503) 
(347) 
(265) 
Mean surface temperature (°C) 
12.2 
11.4 
12.9 
14.4 
14.3 
18.3 
12.7 
Number of fish tagged 
42 
139 
2221 
3002 
(2913 trawl, 89 pot) 
1977 
48 
80 
Size range (cm FL) 
40.8-77.9 
46.8-75.9 
34.8-83.5 
30.7-81.5 
44.5-83.5 
41.4-80.3 
41.9-81.0 
Mean size (cm FL) 
56.2 
54.3 
48.1 
49.7 
57.8 
54.3 
53.6 
Number of recaptured fish and 
5 
24 
322 
393 
489 
8 
13 
percentage of total fish tagged 
(11.9%) 
(17.3%) 
(14.5%) 
(13.1%) 
(24.7%) 
(16.7%) 
(16.2%) 
of 12-20°C indicate that discarded fish may fare poorly 
during periods of elevated surface temperatures (011a 
et ah, 1998; Davis et ah, 2001). The additional stress 
imposed on fish caught in deeper waters may also in¬ 
crease discard mortality rates. Current management 
objectives have resulted in a greater spread of fishing 
effort throughout the year, but survival of discarded 
fish remains a concern in stock assessments. For ex¬ 
ample, total discards in the southern stock in 2013 
were approximately 755 t, and applied mortality rates 
were 20% for fixed-gear fisheries and 50% for trawl 
fisheries (Somers et ah, 2014). 
Objectives 
Our objectives were to examine patterns of movement, 
growth, and survival for sablefish residing in slope wa¬ 
ters off central Oregon. We examined small-scale move¬ 
ments among depths and large-scale movements asso¬ 
ciated with long distance migrations, comparing the 
latter to prior studies of the 2 sablefish stocks. Tagging 
of fish captured at discrete depths and contrasting sur¬ 
face temperatures allowed us to examine the potential 
effects of temperature and depth on discard mortality. 
Growth rates were compared by depth and in relation 
to migration distances. All patterns were compared 
in relation to initial fish size, sex, and time at large, 
where possible. 
Materials and methods 
Fish capture and tagging 
All tagging was conducted off Newport, Oregon. For the 
first tagging event (tagging set 1), fish were captured 
primarily in trawls from 4 chartered fishing vessels 
during 8 trips from February 1996 to May 1998 (Table 
1). Fish were measured, tagged with a uniquely num¬ 
bered Floy FD-94^ nylon spaghetti tag (Floy Tag Inc., 
Seattle, WA) inserted on the left side just beneath the 
anterior end of the first dorsal fin, and immediately 
released. The goal of this tagging effort was to provide 
data for a preliminary evaluation of growth, as well 
as small- and large-scale movements. Boat captains 
selected fishing locations to maximize the number of 
fish available for tagging. A range of depths along the 
outer shelf and upper slope was sampled, with depths 
clustered within 2 groups, designated as depth zone 1, 
which represented fish captured at depths of 141-302 
m, and depth zone 2, which represented fish captured 
at depths of 335-649 m. 
For tagging set 2, fish were captured with pots de¬ 
ployed from 1 vessel at 2 depth ranges (327-366 m and 
1112-1225 m) during 2 trips with expected warm (Sep¬ 
tember 2003) and cool (May 2004) surface temperatures 
(Table 2). Depths were designated as depth zone 2 (to 
match tagging set 1) and depth zone 3. One objective 
of the sampling design was to test for effects of depth 
and surface temperature on discard mortality. The 
numbers of fish tagged were evenly distributed among 
the 4 depth and surface temperature combinations to 
provide a balanced design. Surface temperatures were 
measured during tagging, and bottom temperatures 
were estimated with the Simple Ocean Data Assimila¬ 
tion data set (Carton et al., 2005) and obtained from 
the Environmental Research Division Data Access Pro¬ 
gram server of the NOAA Southwest Fisheries Science 
Center (website). 
Recaptured fish were reported by commercial fish¬ 
ermen, observers, and processors, with varying levels 
of information. For each analysis described below, re- 
^ Mention of trade names or commercial companies is for iden¬ 
tification purposes only and does not imply endorsement by 
the National Marine Fisheries Service, NOAA. 
