Vol. 53 - Alaska Resources Library and Information Services

to early August (Fig. 3.17b), and still have three to four weeks development
before molt to first instar juveniles; an event predicted to
occur from mid-August to September.
Molt frequency of larval red king crabs is estimated to be once
every three weeks, based on a simple division of four months development
time by five larval stages.
Examination of frequency-of-occurrence data
for all years combined (Fig. 3.17b), shows a major shift in the proportion
of larval stages occurs in three-week intervals depicted.
It is
not known from these data, however, if the intermolt duration changes
with stage (e.g. shorter as SI, longer as megalopae) as a function of
temperature and mass, or is rather constant as assumed above. Relative
to oil pollution, it seems reasonable to assume that exposure of larvae
for a week or more would encompass ecdysis of some portion of an
asynchronous population (see Section 8.0 for further discussion of this
point).
Growth of larvae is substantial during this four-month period.
From a mean egg weight of 220 mg dry wt., larvae increase almost
six-fold to 1300 mg as megalopae (Fig. 3.20). The data of Figure 3.20
were obtained by collecting fresh red king crab larvae in the southeastern
Bering Sea, staging, drying and weighing each animal on an
electrobalance. The data not only show the weight gain from one larval
stage to the next, but also the increase in dry weight within a single
stage (i.e. intermolt growth).
Stage II larvae had initial mean weights
of 370 mg/larva but increased to 440 mg/larva prior to the molt from SII
to SIII (Fig. 3.20).
Likewise, the mean weight of SIV larvae was
580