EUPHAUSIID ECOLOGY AND WATER MASS ASSOCIATIONS IN ROSEWAY BASIN MEASURED FROM AN OCEAN GLIDER

Abstract

The goal of this thesis is to quantify spatial and temporal variation in the concentration and distribution of zooplankton, with an emphasis on euphausiid krill, in Roseway Basin, on the Scotian Shelf. We used an autonomous ocean glider with an integrated echosounder and CTD to continuously monitor variation in zooplankton and water masses over two months in autumn 2015. The glider data revealed intra-seasonal variation in euphausiid concentrations that depended upon water mass presence in the basin. I provide evidence that the Nova Scotia Coastal Current plays a significant role in transporting euphausiids in Roseway Basin. Glider-derived estimates of euphausiid concentration were similar in magnitude with those in known baleen whale feeding habitats, indicating that Roseway Basin may represent a viable feeding habitat for whales on the Scotian Shelf. The process-based information provided by the glider is critical for identifying feeding habitat for whales and for determining if prey-field variation explains the presence and persistence of whales to support monitoring and conservation efforts.