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Vol. 53 - Alaska Resources Library and Information Services

Vol. 53 - Alaska Resources Library and Information Services

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populations are probably well protected from benthic pollution by virtue<br />

of the vast size of the species range.<br />

Ecological Vulnerability of Females. One proviso must be integrated<br />

into the topic of acute toxicity. The NAS lease sale area lies adjacent<br />

to the coastal domain of the Izembek Lagoon <strong>and</strong> Port Moller. Spills in<br />

this area could be driven by nearshore currents (Leendertse <strong>and</strong> Liu<br />

1981) <strong>and</strong> transported northeast into shallow water. A very large spill<br />

(in excess of 500,000 bbl) could cover a significant portion of the<br />

coastal domain <strong>and</strong>, in this turbulent, well mixed system, reach the<br />

benthos in unknown concentrations. As shown for past years, a large<br />

fraction of the mature female population sometimes occurs nearshore <strong>and</strong>,<br />

thus, could be vulnerable to acute oil toxicity. If the event occurred<br />

prior to peak egg hatch in early May, then loss of those females <strong>and</strong> any<br />

resultant impact on the population would be exacerbated by loss of a<br />

portion of the annual reproductive effort. Redistribution of mature<br />

females around the SEBS on an annual basis would change the relative<br />

vulnerability of the population as far as exposure in shallow, nearshore<br />

water. Data presented in this report show a shift away from the coastline<br />

in 1983 compared to distributiuon in 1979/80, for example, <strong>and</strong> so<br />

the spatial vulnerability of mature females relative to nearshore spills<br />

would probably be reduced as a consequence.<br />

Effects on Reproduction. The effects of oil need not be manifested in<br />

overt mortality to impact the adults <strong>and</strong>, in turn, younger stages of the<br />

species. Sublethal toxicity might perturb the population through a<br />

combination of physiological <strong>and</strong> behavioral processes that regulate<br />

reproduction. Oil in water <strong>and</strong>/or sediments could affect reproduction<br />

in several ways: 1) Sediment <strong>and</strong> infaunal concentrations of hydrocarbons<br />

become so high that feeding of crabs is curtailed either by loss of prey<br />

(clams, polychaetes,other crustaceans)<strong>and</strong>/or anorexia. Thus, energetic<br />

requirements are not met <strong>and</strong> gamete production is reduced or inhibited.<br />

2) Hydrocarbons are absorbed <strong>and</strong>/or ingested with food <strong>and</strong> deposited in<br />

eggs <strong>and</strong> sperm. At critically high (but as yet unknown) concentrations,<br />

405

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