Seasonal Migration And Distribution Of Female Red King Crabs In A Southeast Alaska Estuary.

Abstract

Seasonal movements and distribution of primiparous and multiparous red king crabs (Paralithodes camtschaticus) were monitored approximately weekly for one year in Auke Bay, Alaska, using ultrasonic biotelemetry. Patterns of seasonal movements were generally similar for all crabs, although movements of multiparous crabs were more conservative and coordinated between individuals. Groups of crabs remained in relatively discrete areas for several weeks before moving, usually as a group, to a different area. The annual range of primiparous crabs (x = 11.9 km$\sp2$) exceeded (P $<$ 0.025) that of multiparous crabs (x = 3.6 km$\sp2$). All crabs displayed distinct seasonal shifts in depth distribution and habitat use. Depth distribution was significantly correlated with photoperiod and the abrupt, synchronous movement of crabs between habitats was coincident with thermohaline mixing. Females displayed a highly aggregated distribution, especially during winter in shallowwater areas. Podding behavior of adult crabs was documented for the first time. Possible causes and functions of this highly specialized behavior are discussed. <p>