While Squamish residents swarmed the shoreline to see more than 200 Pacific white-sided dolphins visit its waters, a pod of orcas was out for lunch.
On Saturday (March 15), spectators watched killer whales hone their hunting skills in the Howe Sound off Nexen Beach, while a large pod of dolphins clustered for safety in the Mamquam Blind Channel.
It was amazing, said Squamish Streamkeeper Jack Cooley, who stood in the rain for more than an hour watching the spectacle.
From the video and photographic documentation, it looks the orcas were Bigg's (transient) whales, said Dr. Lance Barrett-Lennard, Marine Mammal Research Program director at the Vancouver Aquarium. Bigg's are one of two types of killer whales in and around the Georgia Strait, the other being resident whales.
Bigg's orcas have shorter, more pointed dorsal fins. They don't vocalize as often as resident killer whales and rarely stay in one place for more than a few hours. Unlike resident orcas, Bigg's predominantly hunt mammals, mainly seals, sea lions and Dall porpoises.
But on the weekend, they had their eyes on a large pod of Pacific white-sided dolphins, Barrett-Lennard said.
They make a business of being unpredictable, he said, noting the element of surprise and ambush are key to the transient orcas' hunting.
Pacific white-sided dolphins are agile. Instead of going after the dolphins' tails or trying to hit them with their own tails as orcas do with seals the killer whales aim to ram them. They drive the dolphins to the surface, dive under them before driving up into their bodies, sometimes missing and jumping out of the water.
If they can hit it, then likely the dolphin will be crippled, Barrett-Lennard said, noting the orcas only successfully connect with the dolphins about a quarter of the time. The easiest why to get a dolphin is to hunt them into a bay.
Barrett-Lennard said he has seen killer whales hunt dolphins off the central B.C. coast. Once the tide went out, there were a number of dead dolphins on the shore, he said, noting killer whales may stay put if there's an ongoing buffet. A large male orca consumes 100 pounds of food per day and a Pacific white-sided dolphin weighs between 280 and 300 pounds.
One dolphin would feed three killer whales for a day, Barrett-Lennard said.
Until 10 years ago, it was rare to see white-sided dolphins in the Strait of Georgia. The growth of the pod that is commonly sighted around Nanaimo and Cowichan Bay is a testament to the health of local waters, Barrett-Lennard said, noting their numbers are growing.
Scientists estimate the pod includes up to 300 dolphins. The Squamish Steamkeepers' initiative to wrap creosote pilings to encourage the herring spawn seems to be working, he added.
Howe Sound has a larger herring bio-mass than it did for many years, Barrett-Lennard said. I think it is great that they are going into Howe Sound.
Herring had spawned in the channel in February, Cooley said. A second spawn was anticipated on Sunday (March 16).
We wouldn't have had this display of dolphins if they didn't have the herring to catch, Cooley said, noting he expects the dolphins will become regular visitors.
The Vancouver Aquarium has a research hotline to track whales and dolphins. Barrett-Lennard asked that anyone that sees a whale call 1-866-ISAWONE. You can also report them online at www.wildwhales.org.
Video by David Safarik on YouTube -
