Depth and habitat distributions of three species of rockfish (Sebastes) in British Columbia: observations from the submersible PISCES IV

Abstract

I describe a technique to quantify spatial distribution patterns of deep reef-fishes, and apply this technique to inshore rockfish (Sebastes) communities in the Strait of Georgia, British Columbia, Canada. Observations were made along vertical transects between 21–140 m using the submersible PISCES IV. A total of 31 transects were completed at 14 sites during 16 submersible dives. S. elongatus, S. maliger and S. ruberrimus were the dominant rockfish species that were observed. S. elongatus and S. ruberrimus had similar depth distributions, but tended to segregate by habitat type. S. elongatus was most abundant on mud and cobble substrates that interspersed rocky areas. S. maliger and S. ruberrimus were both abundant in complex rock habitats, but tended to segregate by depth. For all three species there was an increase in size with depth. Hence, habitat type and depth were important influences on distribution patterns of this species group.