Oceanographic conditions

Prey abundance, species composition and distribution – how is food quality and quantity changing over space and time? What are the impacts of prey shifts?

The world’s oceans are experiencing pronounced changes.

As the world’s oceans continue to warm, sea ice is lost and important current systems alter course, reductions in marine biodiversity are expected. Already researchers are noting pervasive shifts in the distribution, abundance and composition of zooplankton. Although zooplankton are nearly microscopic organisms (about the size of a grain of rice) they are an important food source for fish and marine mammals. However, how changes in low trophic organisms like zooplankton may scale up to higher trophic species such as toothed and baleen whales is poorly understood. To help answer this gap in knowledge, we collect biological and physical oceanographic data near whales to characterize their prey field.

Technologies Used

OCEAN CONDITIONS

    • Nets with fine mesh sizes are used to collect zooplankton samples from different depths in the water column.

    • These samples are then examined under a microscope to identify and enumerate zooplankton species.

    • Researchers analyze the composition, abundance, and distribution of zooplankton populations to understand their role in marine ecosystems.

    • OPCs are automated instruments that use optical sensors to count and size particles in seawater.

    • They are deployed at discrete depths in the water column to provide real-time data on plankton abundance and size distribution.

    • OPCs are useful for studying variations in plankton populations over time and space, and for assessing the impact of environmental factors on plankton dynamics.

    • This instrument captures images of plankton as it descends through the water column.

    • It provides high-resolution data on the abundance, size, and taxonomic composition of plankton at different depths.

    • The images collected by the profiler allow researchers to study the vertical distribution of plankton and understand their ecological roles in marine ecosystems.

    • These instruments emit sound waves at multiple frequencies and measure the echoes reflected back from organisms in the water column.

    • Multi-frequency echosounders are used to characterize the horizontal and vertical distribution, abundance, and biomass of zooplankton and fish.

    • They provide valuable data for studying predator-prey interactions, migration patterns, and ecosystem dynamics in the ocean.

    • Environmental DNA (eDNA) sampling involves collecting water samples and analyzing them for genetic material shed by organisms present in the environment. 

    • eDNA analysis can identify the genetic signature of multiple trophic species, including zooplankton, fish, and marine mammals.

    • This non-invasive sampling technique provides insights into species diversity, community structure, and ecosystem health in marine environments. We’re fortunate to be working with researchers (Dr. Julie LaRoche) and engineers (Dr. Vincent Siben) from Dartmouth Ocean Technologies and Dalhousie University on this exciting project!

By utilizing these oceanographic sampling techniques, we gather comprehensive data on zooplankton and their interactions with the surrounding environment. This information is essential for understanding the effects of anthropogenic impacts on marine ecosystems.

Video of Calanus spp. Collected off the western shore of NewFoundlandNew Foundland in the Gulf of St. Lawrence provided by Dr. Laura Helenius (Research Associate).

Example of images taken by the Underwater Vision Profiler 6 (UVP) in Iqalujjuaq Fjord in August 2023. Based on manual taxanomic classification we found that A) Chaetognath. B) Ctenophore C) Calanoid Copepod D) Hyperiidea and E) Euphausiacea provided by Caitlin Huard (MSc student).

Oceanographic cage with Conductivity Temperature Depth sensor (CTD) (A), Underwater Vision Profiler (UVP) (B) and Dartmouth Ocean Technologies (DOT) eDNA sampler (C). Photo taken by Iain Grundke (Dartmouth Ocean Technologies).

Our oceanographic sampling team (left to right) Connor Mackie (Dartmouth Ocean Technologies), Hayley McLennan (University of St. Andrews) and Manon den Haan (Dalhousie University).

Oceanographic cage deployed in Cumberland Sound, NU with Conductivity Temperature Depth sensor (CTD), Underwater Vision Profiler (UVP) and Dartmouth Ocean Technologies (DOT) eDNA sampler. Photo taken Katrina Pyne, Hakai Institute.

Rhyl Frith (Dalhousie University) sampling bowhead whale scat for diet analysis.

Example of zooplankton sampled from a net in the Gulf of St. Lawrence during summer 2023. Image provided by Rhyl Frirth (MSc student).

Example of what Calanus spp. Copepods from the Gulf of St. Lawrence looks like under a dissecting microscope. Image provided by Jay Kirkham (PhD Candidate).

Aerial image of our research team collecting biological and physical oceanographic data near a tidal front in Cumberland Sound, NU. Image captured by Katrina Pyne at Hakai Institute.

Team Bowhead

  • MANON DEN HAAN

    Manon Den Haan

    PhD student, Dalhousie University

    Bowhead foraging ecology and energetics  in Cumberland Sound, NU

  • Hayley McLennan

    PhD student, University of St. Andrews

    Using active acoustics to quantify the feeding threshold of bowhead whales in Cumberland Sound, NU. 

  • Alexis Bazinet

    Alexis Bazinet

    MSc student, Dalhousie University

    Bowhead body condition and health in Eastern Canadian Arctic

  • CAITLIN HUARD

    Caitlin Huard

    MSc student,Dalhousie University

    Borealization of bowhead whale copepod prey in Cumberland Sound, NU

Team Right Whale

  • JAY KIRKHAM

    Jay Kirkham

    PhD candidate, Dalhousie University

    Determining the spatial dimensions of risk to foraging right whales in the Gulf of St. Lawrence


  • RHYL FRITH

    Rhyl Frith

    MSc student,Dalhousie University

    Evaluating the energetic consequences of North Atlantic right whales shifting habitats from the Bay of Fundy to the Gulf of St. Lawrence

  • Dr. Laura Helenius

    Dr. Laura Helenius

    Research Associate, Dalhousie University

    Examining the seasonal variability in abundance and quality of Calanus spp. as prey for zooplanktivores in the northeastern Gulf of St. Lawrence 

Associated Publications

McLennan, H1, S. Fortune2, Manon den Haan2*, Alexis Bazinet2*, Martin Cox3, Roland Proud1, Connor Mackie4, Ricky Kilabuk5 and Andrew S. Brierley1†. In Revision. In situ zooplankton density estimates at a foraging site in the Canadian Arctic are below minimum prey thresholds for adult bowhead whales (Balaena mysticetus). ICES Journal of Marine Science  ICESJMS-2024-227.