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Fishery Bulletin 113(3) 
62°N 
61°N 
60°N 
59° N 
58°N 
57°N 
56° N 
55°N 
54° N 
53"N 
62°N 
61°N 
60°N 
59° N 
58°N 
57°N 
56°N 
55°N 
54'N 
53°N 
62°N 
61°N 
60° N 
59° N 
58° N 
57°N 
56°N 
55°N 
54°N 
53°N 
Distributions of morphometrically mature (MM; large-clawed) and 
adolescent (small-clawed) male snow crabs ( Chionoecetes opilio) in 
the eastern Bering Sea during July, based on data collected annually 
(and pooled across years; 1989-2011) during National Marine Fish- 
eries Service summer bottom trawl surveys. Distributions are classi- 
fied within 4 categories of males: (A) small (70-100 mm in carapace 
width [CW]) males with new-shell condition (B) large (>100 mm CW) 
males with new-shell condition, (C) small males with older-shell con- 
dition, and (D) large males with older-shell condition. Distributions 
Assuming, on the basis of the data from 
DSTs, that large commercial-size MM males 
do not migrate inshore far enough, or soon 
enough, to mate with pubescent-primiparous 
females, the most likely partners for pubes- 
cent-primiparous mating were small (70-100 
mm CW) MM males. Adolescent males from 
the Gulf of St. Lawrence have been found to 
mate with pubescent-primparous females in 
the laboratory (Moriyasu and Conan 6 ; Sainte- 
Marie and Lovrich, 1994; Sainte-Marie et ah, 
1997), but their reproductive contribution in 
the field was thought to be limited (Sainte- 
Marie et al., 1999; Sainte-Marie et ah, 2008). 
Instead, small MM males were found to be 
the primary partners of pubescent-primipa- 
rous females (Sainte-Marie and Hazel, 1992). 
It is not known if MM males <100 mm CW 
in the eastern Bering Sea undergo seasonal 
migrations, but given their close proximity to 
primiparous females during summer (Figs. 5 
and 7C), they were the most readily available 
group of males to mate with these females. 
Differences in the male-female mating dy- 
namics of snow crabs from the eastern Bering 
Sea and those from eastern Canada are like- 
ly. Opportunities for different mating associ- 
ations among the various reproductive stages 
(e.g., pubescent-primiparous and multiparous 
females and adolescent and MM males) could 
be greater in areas of steep bathymetry, for 
example, as a result of shorter migratory 
distances (Sainte-Marie et al., 2008) and re- 
lated energetic costs (Foyle et al., 1989). The 
eastern Bering Sea shelf is flatter and wider 
than the Gulf of St. Lawrence. Because snow 
crabs are distributed along depth and tem- 
perature gradients according to their size 
and reproductive stage, the physical separa- 
tion of these different groups may be greater 
over the eastern Bering Sea shelf than over 
the Gulf of St. Lawrence. Despite the geo- 
6 Moriyasu, M., and G. Y. Conan. 1988. Aquari- 
um observation on mating behavior of snow crab, 
Chionoecetes opilio. ICES Council Meeting (C.M.) 
Documents 1986/K:9, 21 p. [Available at web- 
site.] 
Figure 7 legend cont. 
of adolescent males are classified by (E) small 
(70-100 mm CW) and (F) large (>100 mm CW) 
size classes. Relative abundance at each station 
was quantified as the proportion of MM males at 
each station in relation to MM males summed over 
all stations for all years. Dot sizes represent the 
following proportion ranges from smallest to larg- 
est: <0.002; 0.002-0.004; 0.004-0.008; 0.008-0.020; 
>0.020. Values of Zij AVjj are the sum of males cap- 
tured at all stations i for all years j. The black line 
indicates the 100-m bottom-depth contour. 
