Vol. 53 - Alaska Resources Library and Information Services

Kon (1970) reported on the basis of laboratory studies that the
duration of the larval stages of C. opilio was inversely proportional to
temperature over some physiologically acceptable range of temperatures.
This response has been experimentally demonstrated with the larvae of
other crabs as well (Anger and Nair 1979; Johns 1981), and the results
presumably also apply to Chionoecetes spp. larvae in the plankton.
During the course of this study, however, temperature effects on duration
of the larval stages could not be isolated for certain from the
effects of other environmental factors (Incze 1983).
A period of about
30 days for each zoeal stage and a period of at least 30 days for the
megalops stage appears to be a reasonable estimate of the duration of
larval stages of these species over the shelf of the St. George Basin
and outer portion of the middle shelf.
4.6 Vertical Distribution of Larvae in the Water Column
Knowledge of the vertical distribution of larvae is essential to
understanding the role various factors and processes may have in determining
larval distribution and abundance. For example, the influence of
environmental temperature on rates of growth, development and metabolism;
the effects of subtidal- and wind-driven transport on larval distribution
patterns; the impact of predators on larvae; the availability of
appropriate food for larval feeding and the impact of catastrophes, such
as major oil spills, cannot be properly interpreted without fairly accurate
knowledge of vertical distributions.
Estimates of larval abundance
made from oblique plankton tows, such as with Bongo nets, can also be
improved when patterns of depth distribution of larvae are known.
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