Vol. 53 - Alaska Resources Library and Information Services

about 5 mm carapace length caught in September were undoubtedly 1983
young-of-the-year crab. In all months, small juveniles were usually
found inside the 50 m isobath where larvae were rare in 1983, but common
in previous years. It is not difficult to imagine that nearshore 0+
juveniles are the survivors of nearshore larvae, entrained and transported
in slow, longshore currents (Figure 4.1-3) that move counterclockwise
to the northeast into Bristol Bay (Kinder and Schumacher
1981b; Schumacher and Reed 1983). Larvae settle out of this current at
fortuitous points along the NAS based on rates of development, but
likely survive only in areas where appropriate substrate affords refuge
(off Port Moller, Cape Seniavin, Port Heiden, Kvichak and Togiak Bays).
The origin of larvae in high abundance between 50 to 70 m is uncertain.
Possibly they were hatched between Black Hills and Cape Seniavin in
early May, and were transported north-northeast in prevailing currents.
Water conditions in June showed two pockets of colder water (5°C or
less) at points along the 50 m isobath north of 57°N that may have
funneled warmer coastal water between Cape Seniavin and Port Moller
offshore (Figure 3.1-8). Or as suggested previously, larvae in this
area were hatched later than those nearshore and were a separate, more
abundant cohort. The arguments in favor of an offshore cohort are: 1)
colder bottom water temperatures (Figures 3.1-10 and 3.1-11) that may
have slowed somewhat the rate of egg development and thus delayed hatch;
and 2) the greater proportion of younger SII and SIII larvae found in
this region (subarea IB; 50 m isobath border of TB) than elsewhere
throughout the study area where SIII and SIV were common (Figure 3.2-3).
Larvae hatched offshore between 50 and 70 m in inner Bristol Bay were
more difficult to account for as benthic 0+ juveniles in shallower water
and, in fact, such larvae (and the spawning females) were thought to be
superfluous to annual reproductive effort by Armstrong, et al. (1983b).
This notion was based on models of current speed and direction that
considered the water of the eastern middle shelf domain to be essentially
static with virtually no net direction (Kinder and Schumacher
385