198 
Fishery Bulletin 113(2) 
Oocyte color 
Figure 4 
Percent occurrence of oocyte colors seen in 146 female Atlantic wolffish 
( Anarhichas lupus) captured on the Stellwagen Bank National Marine 
Sanctuary, Massachusetts, from 23 May to 8 June 2011. Color range rep- 
resents degree of oocyte development from white (least) to orange-red 
(most). Colors were classified by the same individual by gross visual in- 
spection of frozen, then thawed ovaries. Only one color was assigned to 
each ovary. 
females. Although sexual dimorphism of Atlantic wolf- 
fish has not been evident in captivity, other than swol- 
len “pot-bellied” females in the 4-5 months before 
spawning (Johannessen et al., 1993), historically, males 
tend to be heavier than females throughout the year in 
the wild (Templeman, 1986a). The largest fish captured 
in Templeman’s (1986a) study were a 127-cm-TL male 
and 121-cm-TL female from the Grand Banks in 1966. 
However, more recently, Nelson and Ross (1992) did not 
find any differences in length between 
males and females (n=132), and they 
attributed this lack of differences to 
small sample sizes. 
Total mortality 
If natural mortality CM) is assumed 
to be 0.15 (Keith and Nitschke 5 ), then 
fishing-induced mortality (F) is 0.20. 
The latest stock assessment for Atlan- 
tic wolffish in the GOM estimated F 
at 0.07 in 2010 and a mean F of 0.29 
for the period 2006-2010 (Keith and 
Nitschke 5 ). The differences in methods 
used make it difficult to compare these 
values, but the fact that the estimate 
from our study lies within the range 
found in the stock assessment increas- 
es our confidence in that stock assess- 
ment. An F of 0.20 for fully recruited 
Atlantic wolffish is relatively low and 
consistent with the findings of the lat- 
est stock assessment that overfishing 
is not occurring ( F<F msy Proxy(0.33)). 
Reproductive status 
In the U.S. GOM-GB region, Atlan- 
tic wolffish reach sexual maturity at 
40-47 cm TL, or about 5-6 years of 
age (Templeman, 1986b; Nelson and Ross, 1992; Mc- 
Bride 9 ). Because the smallest fish in this study was 59 
cm TL and eggs were >0.5 mm in diameter in all fe- 
males (Table 4), it is clear that the SBNMS fish were 
mature. Less clear, because of the lack of proper gonad 
McBride, R. 2012. Personal commun. Northeast Fish. 
Sci. Cent., Natl. Mar. Fish. Serv., 166 Water St., Woods Hole, 
MA 02543. 
Table 3 
Numbers of Atlantic wolffish ( Anarhichas lupus; n= 146) with oocytes within the following 
ranges of size (min. to max). Oocytes were collected from ovaries of individuals captured 
from 23 May to 8 June 2011 on Stellwagen Bank National Marine Sanctuary, Massachusetts. 
Minimum oocyte 
diameter (mm) 
Maximum oocyte diameter (mm) 
0.5-0. 9 1.0-1. 4 
1.5-1.9 
2. 0-2. 4 
2. 5-2. 9 
3. 0-3. 4 
3. 5-4.0 
>6.1 
0.5-0. 9 
1 6 
2 
1.0— 1.4 
8 
17 
1 
4 
1.5-1. 9 
18 
25 
2 
2 
4 
2. 0-2. 4 
4 
11 
8 
2 
2. 5-2. 9 
1 
16 
2 
3. 0-3. 4 
6 
4 
1 
3. 5-4.0 
1 
Total 
1 14 
35 
30 
14 
36 
7 
9 
