Vol. 53 - Alaska Resources Library and Information Services

female crabs sampled in late May and early June by National Marine
Fisheries Service surveys have immature (recently extruded) egg masses
(Somerton 1981).
The initial hatchout period of C. opilio larvae was not documented
as well as that for C. bairdi.
There appeared to be a considerably earlier
hatchout for this species, as shown in Table 4.3 with data from
1977 and 1978. Although there is a considerable range in larval densities
shown over time (possibly due to a wider range of sample locations
than was used for C. bairdi), high densities were clearly found by 20
April in both years (sampling started 6 April 1977 and 11 April 1978).
Throughout most of the area of the southeastern Bering Sea sampled in
this study, 1980 and 1981 were both markedly "poor" years for C. opilio
larvae (see later discussion) and collections were not adequate in either
year to define a hatchout curve.
However, larval densities typical
of those two years were also found by middle April.
Data on development
rates of Stage I (SI) zoeae of C. opilio and on the time of appearance
of Stage II
(SII) zoeae of this species in 1981 (see Incze 1983 and following
section) further support the suggestion that significant hatchout
of C. opilio larvae occurred two to three weeks prior to the major hatch
of C. bairdi larvae.
4.5.2 Rates of Larval Development
The rates of development of C. bairdi and C. opilio SI zoeae in the
southeastern Bering Sea were analyzed by examining the ratio of SI to total
zoeae (SI:SI+SII) for each species at stations where at least six
individuals of a species were examined in the sample or subsample. Using
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