From the field: Grey whale tales

Jul 11, 2013

The BC Cetacean Sightings Network, as part of the Vancouver Aquarium’s Cetacean Research Program, spends time each summer surveying the coast of British Columbia investigating the distribution and ecology of cetaceans. 2013 will mark our fifth season using our generously-donated research vessel, “Skana”, and focusing our research on the Central Coast area.

Field season is here at last! June 27th saw the Skana wave farewell to Vancouver as we departed for more northerly waters. In seasons past we have traveled the inside waters between Vancouver Island and the mainland to relocate to our study area on the central coast of B.C. between Port Hardy and Bella Bella. This year, however, we decided to make our way north via the west coast of Vancouver Island. A new adventure!

What did we find along the way? Grey whales! Starting in the mouth of Barkley Sound and continuing past Nuchatlitz Inlet, grey whales were spotted in eight different locations with 18 animals recorded. As typical of greys, they were mostly spotted near sandy-bottom bays, around kelp beds, and close to rocky outcrops. These areas are often full of the mysid shrimp or bottom-dwelling invertebrates favoured as prey by this species. In fact, a foraging grey whale may consume between 250-1100 kg of prey a day in the summer depending on the size of the animal!

The majority of the eastern grey whale population travels past our coast on their migration to their primary foraging grounds in the Bering and Chukchi Seas. However, B.C. has a small summer resident population that is part of the Pacific Coast Feeding Aggregation (PCFA). PCFA is just a fraction of the overall population of Eastern grey whales and represents the animals that spend the summer between northern California to south-eastern Alaska. This small group (estimated to be only a few hundred animals) is most commonly seen along the west coast of Vancouver Island in B.C. With past years of research focused on the central coast and eastern Vancouver Island where grey whales are less abundant, we were excited to spend some time documenting this species. Like many whales, greys can be photo identified. The flank of the animal is used and its unique pattern of mottling helps distinguish one animal from another, as well as their tail flukes.

As we continued north, we also observed several humpback whales, a few porpoise groups, but most abundantly, sea otters. The west coast of Vancouver Island is ground zero for the recovery of the sea otter population in B.C. Once extirpated as a result of the fur trade, sea otters were first re-introduced to B.C. in Checleset Bay near Kyuquot. Since that re-introduction of 89 animals between 1969-1972, the sea otter populations has increased and expanded its range. The most recent population estimate for sea otters on our coast is approximately 5000 animals. They are now found regularly from Clayoquot Sound near Tofino all the way to the McMullin Group on the central coast. Along our survey we encountered multiple rafts (groups of sea otters), as well as many singular animals. In fact, one evening, we were joined in our anchorage by a lone animal grooming nearby.

The first leg of the field season ended in Coal Harbour, near the northwest corner of Vancouver Island. We had been experiencing some problems with the Skana’s stern drive for a couple of days, and decided to haul her out for repairs before we continue further north. Stay tuned for events during leg two of our summer research, starting on July 8.

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From the field: Grey whale tales

Vancouver Aquarium

From the field: Grey whale tales

Vancouver Aquarium

From the field: Grey whale tales

Vancouver Aquarium

From the field: Grey whale tales

Vancouver Aquarium