Physical forcing of space-time variation in the copepod prey-field of right whales in Roseway Basin at diel and tidal scales
Davies, K. T.
Schillinger, D. J.
Hay, A. E.
Taggart, C. T.
MetadataShow full item record
Defining the critical feeding habitat for endangered species is the goal of many marine science initiatives. In the pelagic zone, habitat boundaries are difficult to define statically in space because the prey-field is subject to advection and mixing by regional flow fields. Here we address this issue in relation to defining the critical feeding habitat of the endangered North Atlantic right whale. These whales feed on diapausing, lipid rich copepods that are aggregated in high concentrations, near bottom, in the deep (>100m) basins of the Scotia-Fundy region. We ask can variation in the spatial distribution of the right whale prey-field at short (tidal, diel) time scales be explained by variation in the current regime in Roseway Basin. Current speed and acoustic backscatter (zooplankton abundance) data were simultaneously collected using moorings at three locations in the Basin. Two moorings, fitted with upward looking Acoustic Doppler Current Profilers (ADCP; one 300 kHz and one 600 kHz), downward looking Aquadopp profilers, and CTDs (SBE-37), straddled a sloping region on the edge of the Basin where whales feed and were located within one tidal excursion from one another. This ensured a full profile of current and backscatter estimates and measures of the near-bottom hydrographic properties. The third mooring (upward looking 300 kHz ADCP) was located at the deepest portion of the Basin. The area was concurrently surveyed using a ship-mounted echo-sounder (Simrad, 120 kHz). We illustrate how zooplankton abundance varies in response to tidal advection of water masses and the residual circulation.
Davies, K. T., D. J. Schillinger, A. E. Hay, and C. T. Taggart. "Physical forcing of space-time variation in the copepod prey-field of right whales in Roseway Basin at diel and tidal scales." Canadian Meteorological and Oceanographic Society, McDonald Building 150 Louis Pasteur, Ste 112 Ottawa, ON, K1N 6N5 Canada. [np]. CMOS Congress 2009 - Sea and Sky Come to Life, Halifax, Nova Scotia (Canada), 31 May - 4 June 2009.