A Comparison Between Megafaunal Presence and Oxygen Concentration at Two Sites in the Barkley Canyon, Vancouver Island

Abstract

Barkley Canyon is a submarine canyon located on the west continental margin of Vancouver Island, British Columbia in the Northeast Pacific Ocean. This area is known for seasonal upwelling, which accounts for lower, temporally varying oxygen levels along the margin at depth. Oxygen concentration data from in situ CTD’s and video footage, obtained from Ocean Network Canada installations in Barkley Canyon, were used to examine correlations between megafaunal abundance and diversity, and oxygen fluctuations from two sites at Barkley Canyon. The Upper Slope site is located along the slope ridge and at a depth of approximately 400 meters and the Mid-Canyon site is located within the canyon towards the base at approximately 890 meters. There is a decrease in the number of species present at the Mid-Canyon site, in correlation with the decrease in oxygen concentrations. A similar correlation was not observed at the Upper Slope. Oxygen is necessary for most organisms to live, whose importance increases at depths that contain lower oxygen levels than surface waters.