Macro- and megabenthic communities in the high Arctic Canada Basin: initial findings

We investigated the macro- and megabenthos of the Canada Basin, one of the biologically least known areas of the Arctic deep sea. Macro-infauna was collected with 11 box cores at six stations ranging from 640 to 3,250 m water depth. Total abundance ranged from 3 to 265 individuals 0.04 m(-2) ( 75-6,625 individuals m(-2)) and decreased with increasing depth. Biomass ranged from 0.04 to 228 mg wet weight 0.04 m(-2) ( 1-5,700 mg wet weight m(-2)) and followed the same trend. Polychaetes, crustaceans and bivalves dominated the faunal densities, biomass and species numbers. At Northwind Ridge ( 800 and 1,800 m), apparently historic ( similar to5,000 years BP) fish otolith deposits were abundant. The invertebrate epi-megafauna was qualitatively analyzed from 9.2 h of video and 853 still images collected at four remotely operated vehicle stations. The epifauna was dominated by polychaetes, crustaceans, echinoderms, cnidarians and fish, with most suspension-feeders occurring in the Northwind Ridge area. A total of 90 benthic invertebrate species/taxa from four biogeographic affinities were identified, including at least three new species of Isopoda. The evident low abundances and biomass are in agreement with findings from the Eurasian Arctic deep sea.