Vol. 53 - Alaska Resources Library and Information Services

Ecological Vulnerability. Armstrong, et al. (1983b) discussed in detail
the types and magnitudes of stress that could affect larvae, and also
the spatial and temporal vulnerability of this stage. They criticized
some assumptions about larval biology used in previous models to predict
oil impact (e.g., Sonntag, et al. 1980), and updated biological information
obtained through 1983 in order to better portray possible oil
stress. Information on larvae obtained during the present study helps
to substantiate conclusions made by Armstrong, et al. (1983b) and
improves a sense of the relationship between larval settlement and young
juvenile distribution nearshore. Yet, the relative importance of
nearshore, coastal domain larvae is not so clear given the higher
offshore densities found over Bristol Bay in June 1983.
This life history stanza still seems particularly susceptible to oil
pollution given physiological, ecological and spatial characteristics of
larvae. Data through 1982 indicate that a major portion of the larval
population occurs along the 50 m isobath and probably is transported by
long-shore currents to the northeast as hypothesized by Hebard (1959),
Haynes (1974) and Armstrong, et al. (1983b). Although the frontal
system depicted by Kinder and Schumacher (1981a) is not as well studied
along the NAS as in upper Bristol Bay, its integrity might be such as to
entrain subsurface oil at the front with resultant transport concurrent
with larval crab. Cline, et al. (1981) concluded from methane profiles
originating from Port Moller that material rarely penetrated more than
20 km offshore and was mostly entrained shoreward of the 50 m front
while moving to the northeast, thus substantiating the notion of a
strong front in this region. While movement of oil as a surface film by
winds results in extensive coverage within brief time periods in the
models of Leendertse and Liu (1981) and Pelto and Manen (1983), mixing
of oil into the water column along the 50 m isobath might pose a more
serious threat to red king crab larvae along the NAS for 10-20 days
after a spill.
Larval distribution and abundance in April and June 1983 furnish
new information on three points: 1) there is probably considerable
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