DISTRIBUTION OF POGONOPHORA (TUBE-WORMS) IN BRITISH-COLUMBIAN FJORDS

The large perviate pogonophore Polybrachia canadensis, previously known from deep water off the west coast of British Columbia (B.C.), Canada, and from Tasu Inlet on the west side of the Queen Charlotte Islands, has been found at 6 stations along Rivers Inlet/Moses Inlet, a mainland B.C. fjord complex opening from Queen Charlotte Sound. The pogonophore was a dominant element in the benthic macrofauna. It was not found in samples from nearby Seymour and Belize Inlets, a smaller and shallower fjord complex to the south of Rivers Inlet. Pogonophora have not been seen in any samples from the southern B.C. fjords sheltered by Vancouver 1. or the inlets along its west coast. Perviate pogonophorans such as Polybrachia live in reducing sediments and are nourished by endosymbiotic chemoautotrophic bacteria that derive energy from particulate sulphides in the sediment. It is unlikely that reducing conditions that produce such sulphides are any different in the southern B.C. fjords. Explanations suggested for the differences in distribution of the pogonophores include greater density and stability of the bottom waters of the northern fjords and their proximity to the deep sea population. The presence of a sizeable deep-sea pogonophore at 200 to 300 m depth in the northern B.C. fjords is not paralleled in the Norwegian fjords.