Glacial Fjords in Glacier Bay National Park: Nursery Areas for Tanner Crabs?

Abstract

During summer 2002, the U.S. Geological Survey Glacier Bay Field Station conducted a systematic survey for king and Tanner crab in Glacier Bay. The distribution of Tanner crabs was segregated spatially by size class, with adults predominating in some areas and juveniles in others. Almost half (44 percent) of the juvenile crabs in the survey were caught in Wachusett Inlet and Scidmore-Charpentier Inlet, narrow glacially-influenced fjords where adults were scarce. Where high numbers of juveniles occurred next to high densities of adults in the central bay, juveniles were associated with shallower depths. However, in Wachusett and Scidmore-Charpentier Inlets, where adults were scarce, adults were associated with shallower depths. Because adults prey on or compete with juveniles, the distribution of juveniles could be driven by the distribution of adults. Areas where adults are scarce, such as glacially influenced fjords, could serve as refuges or possibly nursery areas for juvenile Tanner crabs.