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Vol. 53 - Alaska Resources Library and Information Services

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months within a single year can be seen by comparing larval abundance<br />

for April, May <strong>and</strong> June during PROBES 1978 (Fig. 6.20 a <strong>and</strong> b). Distribution<br />

in April was widely spread over the outer shelf domain <strong>and</strong><br />

greatest concentrations were found beyond the shelf break (Fig. 6.20a).<br />

Distribution in May <strong>and</strong> June 1978 seemed to be concentrated mainly into<br />

2 b<strong>and</strong>s; one just west of the 100 m isobath <strong>and</strong> one just beyond the<br />

shelf break at the 200 m isobath.<br />

By this time of year some larvae were<br />

found up in the middle shelf domain.<br />

The highest concentration of<br />

larvae (12,000 larvae/100 m 2 ) was found at the western tip of Unimak<br />

Isl<strong>and</strong>.<br />

Further work to identify the species within the hippolytid<br />

group would help to delineate distribution patterns of individual<br />

species.<br />

Figure 6.21 illustrates mean larval hippolytid densities by month<br />

<strong>and</strong> by years in stratum 3 just west of the 200 m isobath.<br />

consistently<br />

high mean larval densities (1000-2400 larvae/100 m 2 ) were found in the<br />

months of April, May, <strong>and</strong> June in stratum 3 during the years 1977-1981.<br />

By comparison, slightly lower mean larval densities (600-1650 larvae/100<br />

m 2 ) were found during May <strong>and</strong> June in stratum 2 during those years.<br />

A more complete picture of mean larval densities for hippolytids is<br />

given in Table 6.7 for PROBES May <strong>and</strong> June 1978 data. Strata beyond the<br />

shelf break again had the highest mean densities which were three-fold<br />

greater toward the Aleutian Isl<strong>and</strong>s (stratum 4)<br />

than toward St. George<br />

Isl<strong>and</strong> (stratum 7).<br />

Hippolytid larvae were found from 0-80 meters in the water column.<br />

Figure 6.22 illustrates the larval depth distribution of hippolytids<br />

745

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