Vol. 53 - Alaska Resources Library and Information Services

esulted from the apparent concentration of crab larvae along the 50 m
isobath. Addition of the other independent variables in multiple
regressions did not meet criteria for significance.
3.2.2 Vertical Distribution
During cruise 83-1 (April-May), a diel series of horizontal plankton
tows was conducted at station PM350. The 40, 30, 20 and 10 meter
samples were collected with a Tucker trawl; the surface sample was
collected with a Sameoto Neuston sampler. The sampling was conducted at
local noon, dusk, midnight and sunrise. The resulting larval red king
crab densities are shown in Figure 3.2-4, and show strong evidence of
diel vertical migration. No larvae were collected at the surface. The
noon and midnight samples exhibit the greatest difference in vertical
distribution; the dusk and dawn samples are intermediates.
During cruise 83-3 (June), a single vertical series of horizontal tows,
0-50 m, was conducted with the Tucker trawl. The larval red king crab
densities are presented in Figure 3.2-5. This figure also indicates the
zoeal stage distribution of the samples. The results do not show any
difference in vertical distribution between stages. The two larger
samples, from 20 and 50 m depth, contained very similar proportions of
zoeal stages 2, 3 and 4.
3.3 Larval Development and Growth
The most appropriate time series by which to measure larval development
was collected in the Port Moller subarea. Samples were collected at six
times: 23-25 April; 1-2 May; 27 May; 6-8 June; 14-16 June; and 11-13
September (Table 3.3-1). Larvae were present from April until mid-June.
First stage zoeae, though present until mid-June, were most abundant in
early May. The next three zoeal stages were sequentially predominant
over the second through fourth visits off Port Moller. This may be seen
in Figure 3.3-1, which has averaged the results from the two visits
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