Vol. 53 - Alaska Resources Library and Information Services

et al. 1975; Donaldson et al. 1980); 50% maturity in C. opilio females
occurs at about 50 mm carapace width in the Gulf of St. Lawrence (Watson
1970) and the southeastern Chukchi Sea (Jewett 1982), and slightly more
than this in the Sea of Japan (Ito 1970).
These data and size frequency
plots of female crab of the two species found in the southeastern Bering
Sea (e.g., Pereyra et al. 1976) provide an approximation of the size of
sexually mature crabs in the study area.
Fecundity varies with size and reproductive year of these crabs.
Haynes et al. (1976) estimated the number of eggs from 42 female C.
bairdi of mixed spawning history (primiparous and multiparous spawners)
from the southeastern Bering Sea in the autumn (September-October).
Using a regression equation relating number of eggs to carapace width
gives an estimate of about 175,000 eggs per 95 mm female, which roughly
corresponds to the average mature female C. bairdi from the 1975 survey
of the southeastern Bering Sea (Pereyra et al. 1976:325).
The regression
estimate of number of eggs produced by an average size, 60-65 mm carapace
width, female C. opilio is about 40,000 eggs for primaparous
spawners from the southeastern Bering Sea (23 specimens) and multiparous
spawners from the Gulf of St. Lawrence (99 specimens).
[The
numbers are not strictly comparable because the St. Lawrence crabs were
caught in spring and presumably had lost part of the egg mass during
winter (Hilsinger 1976)].
Most of the difference in female egg production
between the two species appears to be due to differences in average
size of the crab.
Haynes et al. (1976) found similar egg numbers for
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