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Vol. 53 - Alaska Resources Library and Information Services

Vol. 53 - Alaska Resources Library and Information Services

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which provides for adequate food (i.e., hydroids <strong>and</strong> bryozoans) <strong>and</strong><br />

protection from predators (see discussion in Armstrong, et al. 1983b).<br />

The distribution of such suitable substrates in the study area was<br />

extremely patchy <strong>and</strong> it is believed that settling in areas where such<br />

substrates are absent or limited would hasten natural mortality.<br />

The substrates inhabited by juvenile red king crabs during this study<br />

also supported a characteristic attached invertebrate fauna, primarily<br />

stalked sea squirts (Boltenia ovifera), bryozoans, <strong>and</strong> colonial tubedwelling<br />

polychaetes in the Kvichak Bay area. Although it appears that<br />

a direct relationship exists between the distributions of red king crabs<br />

<strong>and</strong> certain attached epifaunal taxa, the relationships are not yet<br />

clearly defined. Samples of Boltenia ovifera, for example, indicated<br />

that their greatest concentration was in the 50-70 m deep area of the<br />

inner Bristol Bay sampling subarea; no red king crabs younger than age<br />

3+ were found in this area, even though this was the area of greatest<br />

pre-settlement larval concentrations during June.<br />

Although YOY in the present study were found in depths of 20-50 m,<br />

successful settlement is known to take place in shallower as well as<br />

deeper waters. In Kodiak Isl<strong>and</strong> waters, young crabs one to 12 months<br />

old were commonly found in the littoral zone (Powell <strong>and</strong> Nickerson<br />

1965). The maximum depth at which post-larval crabs smaller than 16 mm<br />

have been captured was 106 m off Kodiak Isl<strong>and</strong> (Powell <strong>and</strong> Nickerson<br />

1965). The Japanese king crab tangle net fishery in the eastern Bering<br />

Sea from 1956 to 1959 captured 5,495 juvenile crab from 2 to 33 mm<br />

carapace length (INPFC 1960). They were caught 139 to 213 km northwest<br />

<strong>and</strong> seaward of Port Moller, at an average depth of 55 m.<br />

The hypothesis that post-larval survival is related to settlement onto<br />

appropriate "refuge" habitat (Armstrong, et al. 1983b) is supported by<br />

the apparent distribution of juvenile crabs found in this study. This<br />

refuge habitat is thought to consist of gravel or larger-sized substrates<br />

inhabited by any of several attached epifaunal invertebrate<br />

394

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