Vol. 53 - Alaska Resources Library and Information Services

megalopae.
These combinations of years and larval stages are similar to
data for red king crab (Fig. 3.17a and b). There is, however, an
indication that larval hatch and, therefore, metamorphosis might occur
somewhat earlier for blue king crab based on data of 1981. All larvae
in early July were megalopae and many were approaching the molt to first
instar juveniles. Almost 50% of megalopae held in rearing chambers
onboard ship molted to first instars within a week of capture (by July
14; D. Armstrong, University of Washington, unpublished data).
Metamorphosis to the benthos for blue king crab might, therefore, occur
by mid to late July; a month earlier than predicted for red king crab.
3.4.4. Molt Frequency and Growth
Red King Crab: Data on molt frequency for red king crab larvae were
previously summarized in Figures 3.17a and b. A preliminary analysis of
frequency of occurrence of various larval stages was done on data of
1978 (Fig. 3.19; Armstrong et al. 1981). Based on the proportion of
each larval stage (SI, II, II, IV, megalops) in samples from four
cruises between April 10 to June 29 (see Section 2.0 for cruise maps),
it was estimated that larvae molt every 2.5-3.0 weeks (Fig. 3.19). If
so, then the elapsed time of development from hatch to metamorphosis
would be about 12.5-15.0 weeks, or about 3.0-3.5 months. However, a
summary of larval stage data from all years 1976 to 1982 combined,
indicates that development might take 4.0 to 4.5 months from hatch to
metamorphosis (Fig. 3.17b). Although annual hatching time will vary
(section 3.4.3), mid-April seems a reasonable annual time to expect the
hatch of P. camtschatica larvae. Megalopae are common from early July
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