Vol. 53 - Alaska Resources Library and Information Services

These results are comparable to those of Tarverdieva (1978) for red
king crab in Bristol Bay during September. The two peaks in feeding found
by Tarverdieva (op. cit.) also occurred at 0300 and 1300 h but in contrast
to the findings here the nocturnal peak was higher than the diurnal one.
During the long photoperiods of June, a nocturnal feeding rhythm present)
at other seasons may break down.
The dry weight of stomach contents standardized by crab wet weight was
a clearer indicator of diel changes than the volume of solid contents as a
percentage of maximum stomach volume. The percentage of stomachs with
soft tissue followed the diel trends in dry weight of stomach contents
(Figure 11).
DAILY RATION
Using the diel feeding chronologies and the clearance rate equation
from Table 2, daily rations in June and August were calculated. Juvenile
king crabs in August consumed slightly less than twice the dry weight of
material consumed in June (Tables 5 and 6). The June daily ration for
juvenile king crab was 6.30 mg dry weight per g crab wet weight per day;
the August daily ration, 11.92 mg dry weight per g crab wet weight per
day.
The daily ration determined by Tarverdieva (1978) for adult king crab
was 3.1 mg/g crab wet weight, about 1/4 to 1/2 of the daily rations. The
difference between the calculations here and Tarverdieva's could be a
reflection of seasonal differences. More likely it is due to correction
for clearance rate in the calculations.
From the daily rations, dietary composition data and caloric
equivalents from the literature, a schedule of the energy derived from
various prey items was calculated and appears in a following section.
DIETARY COMPOSITION
The Frequency of Newly Discovered Prey as a Function of the Number of
Stomachs Examined
Following Vesin et al. (1981), the frequency of newly-discovered prey
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