Vol. 53 - Alaska Resources Library and Information Services

and then increased through 1979 (Otto 1981a).
However, abundance estimates
for total male king crab in this area have declined from 181 million
animals in 1977 to 129 million in 1982 (Otto et al. 1982).
Most
importantly, estimates of sublegal males one to two years from entering
the fishery have declined nearly threefold from 64 to 17 million, leading
to predictions of several consecutive years of poor fisheries.
Abundance
estimates of legal male crabs dropped from over 45 million animals
in 1979 to about 5 million in late 1982 (Fig. 3.5; Otto et al. 1982; M.
Hayes, NMFS, Seattle, pers. communication), which has resulted in severe
reductions in commercial landings from 130 million lb to less than 4
million in the same period (see Section 1.0).
Change in abundance of king crab populations is an important biological
factor to consider later in discussing oil impacts.
Cycles of
abundance suggest that year class failure or success may be based on
survival of critical life-history stages such as larvae or young juveniles,
probably in nearsnore habitats.
Annual instantaneous mortality
rates of juvenile and sublegal, sexually mature crab are estimated to be
low, about .10 until entering the fishery (Balsiger 1976; Reeves and
Marasco 1980).
Consequently the magnitude of a future fisheries cohort
is largely determined by the reproductive success and survival of larvae
and young-of-the-year (0+ crab) in nursery areas.
Vagaries of temperature,
food supply, and predator populations are factors affecting survival,
now the question of potential oil perturbations could add to natural
pressures on larval and juvenile populations and further suppress stocks.
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