Right whale ecology in the northwest Atlantic ocean

• Main Author: Baumgartner, Mark F.
• Other Authors: Mate, Bruce R., Williamson, Ken, Ramsey, Fred, Miller, Charlie, Abbott, Mark, College of Oceanic and Atmospheric Sciences, Oregon State University. Graduate School
• Format: Doctoral or Postdoctoral Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Right whales > Ecology > North Atlantic Ocean; Lower Bay; Calanus finmarchicus; Eubalaena glacialis; North Atlantic; North Atlantic right whale; Northwest Atlantic; Copepods
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/rv042w31r

The ecology of the North Atlantic right whale (Eubalaena glacialis) was examined at three spatial scales during the summer and early fall on their northern feeding grounds. The diving and foraging behavior of right whales was investigated at spatial scales of hundreds to thousands of meters by tagging right whales with time-depth recorders to document their diving behavior. The vertical distributions of temperature, salinity and copepods were measured along the tagged whale's track with a conductivity-temperature-depth instrument (CTD) and an optical plankton counter (OPC). Right whales were observed diving to and presumably feeding on discrete layers of their primary prey. older stages of the calanoid copepod Calanus finmarchicus, aggregated just above the bottom mixed layer. Simultaneous visual and oceanographic surveys conducted in the lower Bay of Fundy and Roseway Basin were used to examine right whale distribution at spatial scales of tens of kilometers. Right whale occurrence was associated with greater depths and thicker bottom mixed layers in these regions. There was additional evidence of an association between right whales and ocean fronts in Roseway Basin. Right whale distribution was also examined on spatial scales of hundreds of kilometers by outfitting whales with satellite-monitored radio tags. Movements of the tagged whales were compared to climatological and remotely-sensed environmental datasets to elucidate habitat preferences. The tagged whales moved extensively throughout the Gulf of Maine and western Scotian Shelf where they frequented shallow basins with cold bottom waters, but avoided deep, comparatively warmer basins. Two of the right whale ecology studies described here depended on the OPC for measures of right whale prey distribution and abundance. A final study was conducted to investigate the response of the OPC to C. finmarchicus copepodite stage 5 (CS). Comparisons between collocated OPC casts and zooplankton net samples indicated that the OPC was adept at detecting C. ...