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Vol. 53 - Alaska Resources Library and Information Services

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on larvae hatched elsewhere, including areas south of the <strong>Alaska</strong> Peninsula<br />

(Hebard 1959; Haynes 1974).<br />

Hebard (1959) calculated that larvae<br />

hatched at Amak Isl<strong>and</strong> could be transported over 60 miles to the northeast<br />

<strong>and</strong> metamorphose at Port Moller (net current speed of 0.04 knot<br />

moving northeasterly along the North Aleutian Shelf; Kinder <strong>and</strong><br />

Schumacher 1981, show a current speed of 2-5 cm/sec in that region).<br />

He<br />

further discussed possible transport of larvae from south of the Peninsula<br />

through Unimak <strong>and</strong> False Pass.<br />

Haynes (1974) adds credence to this<br />

supposition by showing a northernly dispersion of king crab larvae off<br />

the southwest tips of Unimak Isl<strong>and</strong>, <strong>and</strong> a northeast shift in areas of<br />

larval abundance from Black Hills into Bristol Bay (May-July, 1969 <strong>and</strong><br />

1970; this pattern may in part be due to inadequate spatial sampling).<br />

Transport of larvae by currents is also important to consider in predicting<br />

oil impacts.<br />

Oil reaching relatively unproductive areas of the<br />

North Aleutian Shelf (low female abundance, few larvae hatched) could<br />

still be lethal if larvae are transported through such contaminated<br />

areas.<br />

Alternatively, oil <strong>and</strong> larvae could be transported together in a<br />

water mass resulting in relatively long-term exposure of sensitive zoeal<br />

stages to hydrocarbons.<br />

Temperature is considered one of the most crucial physical factors<br />

affecting survival <strong>and</strong> growth of larvae, <strong>and</strong> Kurata (1960, 1961) calculated<br />

that 460 degree-days were required to progress from hatch to metamorphosis.<br />

Lethal temperatures are those greater than 15°C or lower<br />

than 0.5-1.8°C (Kurata 1960).<br />

He found greatest survival of zoeae between<br />

5-10°C <strong>and</strong> formulated an equation that relates developmental time<br />

to temperature.<br />

Time from egg-hatch to molt of stage I (SI) to stage II<br />

542

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