194 
Fishery Bulletin 113(2) 
Table 1 
Summary of data from trips dedicated to sampling of Atlantic wolffish ( Anarhichas lupus) from 23 May to 21 June 2011 on 
Stellwagen Bank National Marine Sanctuary, Massachusetts. Catch per unit of effort (CPTJE) was measured as the number 
of Atlantic wolffish captured per hour. Mean tow durations and bottom temperatures are given with standard errors in pa- 
rentheses. Substrate types were identified by fishing captains: G=gravel, HS=hard sand, SS=soft sand, S=sand, SG=sandy 
gravel, euth=euthanized. 
Number Number Mean Mean SD 
Total of of tow SD Tow Speed bottom bottom 
Total wolffish wolffish wolffish Fishing duration duration range Depth temp temp 
Trip 
Date 
tows 
caught CPUE 
euth. 
tagged 
l period 
(min) 
(min) 
(knots) 
(m) 
(°C) 
(°C) 
Substrate 
1 
23 May 
3 
107 
22.8 
107 
0 
5:35-10:55 
95.33 
6.81 
2.7-3. 1 
28 
6.06 
0.79 
G 
2 
26 May 
4 
187 
37.8 
187 
0 
4:22-10:35 
73.00 
9.06 
- 
31-40 
6.40 
0.03 
HS, G 
3 
7 June 
6 
7 
1.8 
7 
0 
8:30-13:33 
35.50 
9.44 
2. 5-3.0 
29-39 
- 
- 
HS, G 
4 
8 June 
4 
3 
1.2 
2 
1 
8:18-13:05 
55.25 
13.96 
2. 8-3. 2 
29-35 
5.00 
0.00 
HS, SS, G 
5 
10 June 
5 
2 
0.6 
0 
2 
6:44-12:15 
41.80 
15.37 
2. 6-2. 7 
29-36 
5.75 
0.71 
HS, SS, G 
6 
13 June 
7 
9 
2.4 
0 
9 
7:15-12:58 
34.14 
7.38 
2. 5-2. 9 
28-46 
5.53 
0.39 
S, SG, G 
7 
16 June 
8 
6 
1.2 
0 
6 
7:30-13:12 
26.88 
11.28 
2. 5-2. 9 
27-38 
6.51 
0.29 
G, S, SG 
8 
17 June 
5 
29 
10.8 
0 
26 
7:49-12:54 
32.33 
3.08 
2. 6-2. 7 
28-38 
6.70 
0.33 
SG 
9 
20 June 
5 
5 
1.8 
0 
5 
8:50-13:35 
39.40 
7.64 
2. 7-2. 8 
29-37 
- 
- 
SG 
10 
21 June 
6 
40 
18.6 
0 
37 
7:37-12:57 
33.00 
15.11 
2. 8-2. 9 
27-38 
6.00 
0.28 
SG 
tory analyses. The remaining sampling days yielded 85 
wolffish that were tagged and released for a separate 
study, and 6 wolffish were released untagged because 
of poor condition. As a result of damaged caudal fins, 
13 euthanized fish (7 females and 6 males) were ex- 
cluded from analyses of size and growth. 
Age, growth, and sex 
Annuli in otolith sections were easily discernible as 
thin hyaline zones. As growth slows in older fishes, the 
annuli form closer together, requiring a higher mag- 
nification and thinner sections to enumerate them ac- 
curately. Coefficients of variation between each of the 
3 readers were 2.93%, 2.60%, and 2.57%. Atlantic wolf- 
fish captured from late May to early June 2011 ranged 
in age from 7 to 33 years old with a mean (1 stan- 
dard deviation [SD]) age of 20.1 years (SD 4.5; Fig. 
2A), with equal numbers of males and females caught 
(% 2 =0.1617, P=0.69). Sexual dimorphism was evident 
in this group with males being longer (Mann- Whitney 
U statistic ((71=8147.5, P<0.001; Fig. 2B) and slightly 
heavier ((7=9586.5, P=0.014), although some of these 
differences may be attributed to the males also being 
older than the females ((7=8313.0, P<0.001; Table 2). 
Total mortality 
The age at full recruitment to the trawl gear was 21 
years (Fig. 2A); therefore, age 22 was used as the start- 
ing point for the Chapman-Robson calculation. With 
that calculation we estimated that Z was 0.35 (stan- 
dard error 0.034). We explored the sensitivity of this 
estimate to the choice of starting age by running the 
analysis with starting points of 21 and 23 years. The 
starting age had little effect on the estimate; results 
for Z were 0.36 and 0.38 for starting ages 21 and 23, 
respectively. 
Reproductive status 
Gonad size (weight) increased with increasing fish size 
(female W: coefficient of correlation (r) 0.665, P<0.05; 
male W: r=0.408, P< 0.05; female TL: r= 0.632, P<0.05; 
male TL: r=0.781; P<0.05) and age (females: r=0.590, 
P<0.05; males: r=0.408, P<0.05) in both male and fe- 
male Atlantic wolffish. In females, GSI was correlated 
positively with age (r=Q.463, P<0.Q5) but not in males 
(r=0.097, P=0.258; Fig. 3). Mean GSI values ranged 
from 0.0003 (SD 0.0) at age 16 to 0.0008 (SD 0.0002) at 
age 27 in males, whereas, in females, they ranged from 
0.003 (SD 0.0) at age 7 to 0.029 (SD 0.016) at age 26. 
Female reproductive state was not easy to classify 
because ovaries were frozen and then thawed instead 
of inspected fresh or preserved in a fixative; as a result, 
only 146 samples were usable, and, even so, interpreta- 
tion was difficult. The majority of oocytes ranged from 
yellow to orange in color (Fig. 4), and all inspected 
oocytes were >0.5 mm (Table 3), indicating that all 
females were mature and most of them were in pre- 
spawning stages (Gunnarsson et al., 2006). 
Feeding ecology 
Atlantic wolffish sampled (n=286) were actively feed- 
ing; only 2 stomachs were empty. The feeding index 
