Vol. 53 - Alaska Resources Library and Information Services

protection against predators, as well as to organize the crabs into a
coordinated group, so that, acting as a unit rather than as individuals,
they can benefit from their coexistence (Powell 1974).
The following is
an account of a pod observation near Kodiak Island (Powell and Nickerson
1965):
"On two occasions elongated dome-shaped piles of crabs were
observed lying parallel to the beach at depths of four to 35
feet. These piles appear to be numerous pods joined in a
line. On February 19, 1961, the first group of an estimated
6,000 crabs averaging 30 mm was observed and described in
field notes as a long windrowed pile. A similar observation
on April 25, 1962 revealed an estimated 500,000 crabs 34 to 98
mm in carapace length having modes at 61 and 84 mm. One foot
from an end of the 12-foot zig zag pile was a pod of approximately
1,000 crabs, giving rise to the idea that spherical
pods form elongate piles when they congregate. Thousands of
other crabs remained scattered and feeding."
Pods have been observed during every month of the year, and all of them
contain both males and females of similar size and of the same age.
Most podding crabs are between 2 and 3+ years old (29-73 mm), although
the above observation testifies that crabs with a mode of 84 mm were one
of the two distinct size classes in a pod.
Few pod-sized crabs (29-73 mm) were collected during the three sampling
periods of 1983. During the April-May and June sampling, age 2 and 2+
crabs were rarely found. However, ages 3 and 3+ were more numerous,
mainly occurring at deeper stations (stations TB350, TB550, BB557 and
PH350) than the previous age group. In September, ages 2, 2+ and 3 were
absent and only one age 3+ crab was found. The data collected do not
indicate that crabs were sampled while podding. Although each station
was briefly sampled, it is expected that if a pod was sampled there
would be a high number of similar-sized individuals. Among those
stations that yielded pod-size crab both the quantity and the proportion
at podding size were low. Presumably the lack of pod-size crab in
September is a reflection of the lack of effort in central Bristol Bay,
however, it may also be due to their patchy transient nature. Podding
has been documented on the North Aleutian Shelf near Akutan and Unalaska
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