Vol. 53 - Alaska Resources Library and Information Services

three-day period in June showed rather similar proportions; from 60 to
90 percent of the larvae were SIII and SIV.
Peak hatching may have occurred a week or two later in other parts of
the species range encompassed by strata for Kvichak and Togiak Bay and
Inner Bristol Bay (Figure 3.2-3). Frequency of occurrence of larval
stages in these strata showed substantially fewer SIV and more SIII
larvae, and in the Togiak strata (TB) up to 45 percent SII. Particularly
in the case of Togiak, stations with high proportions of earlier SII
larvae were those near the 50 m isobath on the edge of the Inner Bristol
Bay (IB) stratum.
The possibility that colder water temperatures may have caused later
hatchout in the area of Bristol Bay between 50 to 70 m is suggested by
data for June 1983. Although near-surface temperatures were essentially
the same in that region as elsewhere in June (5° to 7°C, Figure 3.1-8),
bottom water temperatures were still 3° to 4°C (Figure 3.1-11), having
been about 1°C in April (Figure 3.1-10). An ovigerous female caught in
the area during the June cruise had eyed eggs still unhatched in early
summer. Regional and interannual differences in bottom water temperature
may significantly affect the rate of embryonic development in the
egg and, in turn, the appropriate time of hatch each year (Armstrong, et
al. 1983b). The occurrence of many SII larvae in the offshore area of
Togiak in mid-June (stations collected June 12-14) indicates that they
had hatched in the last week of May (based on the molt frequency data of
Armstrong, et al. 1983), some three weeks later than the cohort off Port
Moller.
Correlation to Physical Factors. Larval horizontal distribution and
abundance were analyzed for relationships with station depth, salinity
and temperature at 10 m, time of day when collected, and Julian date.
Station depth yielded the sole significant correlation coefficient
(r=[superscript]+0.344;
171 degrees of freedom), explaining only 11.8 percent of the
variability in the data set.
Residuals indicated the correlation
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