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Vol. 53 - Alaska Resources Library and Information Services

Vol. 53 - Alaska Resources Library and Information Services

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shows high similiarity between the stations from August <strong>and</strong> less<br />

similiarity between the stations from June.<br />

The results confirm the hypothesis that juvenile king crab depend upon<br />

soft-bodied readily digested prey items to a greater extent than<br />

previously thought <strong>and</strong> indicate that polychaete worms are a consistent <strong>and</strong><br />

substantial proportion of the crab's diet by bulk <strong>and</strong> by energy. The diet<br />

of the smallest juveniles contains soft-bodied meiofaunal groups detected<br />

immunologically but not observed in the diet of larger juveniles.<br />

POTENTIAL IMPACTS FROM OIL AND GAS DEVELOPMENT ON JUVENILE CRABS<br />

Potential impacts from oil <strong>and</strong> gas development could derive from<br />

habitat disturbance, exposure to contaminants from platform discharges,<br />

<strong>and</strong> oil spills. The assessment of risk from these potential impacts<br />

requires judgments concerning, first, the manner <strong>and</strong> extent to which<br />

disturbance <strong>and</strong> contaminant exposure is likely to occur <strong>and</strong>, secondly, the<br />

direct <strong>and</strong> indirect consequences likely given the anticipated extent of<br />

disturbance <strong>and</strong> exposure. The potential impacts differ with life stage.<br />

This study was concerned with evaluating possible impacts on juvenile king<br />

crab. Because of their different habitats <strong>and</strong> diets, impacts are assessed<br />

separately for the smallest juveniles (CL 40 mm).<br />

Assessment of impacts requires consideration of the highly aggregated<br />

or clumped distribution of juvenile king crab. The larger juveniles (CL<br />

>40 mm) were essentially exclusively concentrated off Port Moller in water<br />

depths of 45 to 75 m. In this region larger juvenile king crab appear to<br />

aggregate along the seaward side of an oceanographic structural front now<br />

being studied by other NOAA/OCSEAP investigators. The temporal changes in<br />

the distribution of the larger juveniles may be related to movements in<br />

the front's position. The thought that the shallow nearshore zone north<br />

of the <strong>Alaska</strong> Peninsula held abundant juvenile king crab was not confirmed<br />

by this survey for the larger juveniles. The smallest juvenile king crab<br />

do occur in the nearshore zone amid patches of cobble <strong>and</strong> rock with<br />

abundant epifauna. These patches provide food <strong>and</strong> shelter from predation<br />

in an area of open, high-energy s<strong>and</strong>y bottoms. More detailed information<br />

on the distribution of juvenile crabs along the North Aleutian Shelf will<br />

come from another NOAA/OCSEAP study now in progress. The current<br />

perception of juvenile crab distribution indicates that for the smallest<br />

juveniles impacts from disturbance <strong>and</strong> platform discharges are unlikely<br />

whereas impacts from oil spills need consideration. For the larger<br />

juveniles (CL >40 mm) potential effects from disturbance, discharges <strong>and</strong><br />

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