Orca sighting in Vancouver inner harbour shows health of transient killer whale population: researcher
Vancouverites were thrilled Tuesday with an up-close look at a visiting pod of orcas, who made their way as far east as the Second Narrows Bridge in the city’s inner harbour.
But the visitors weren’t members of the region’s famously endangered southern resident population.
They were, like the pod of orcas spotted hunting just off the shore of Bowen Island last weekend, transient, or “Biggs” killer whales — a genetically different group of whales that’s seen a resurgence in recent years.
Tuesday’s visit was from a well-known family of transients known as the T101 group: the 45-year-old matriarch T101 and her three sons, T102, T101A and T101B, according to Caitlin Birdsall, a researcher with the BC Cetacean Sighting Network at Ocean Wise.
“Transient killer whale populations are doing quite well right now, and over the last decade or so we’ve actually seen them start to use the Salish Sea and the Strait of Georgia more and more,” said Birdsall.
It’s a shift Simon Pidcock, owner and lead captain of whale watching company Ocean Ecoventures says he sees daily on the waters.
“It’s been a huge shift, I’ve been doing this for 17 years now, and when I started 99 per cent of our encounters were the southern resident killer whales,” he said.
“In the last four years we’ve seen a huge shift and its come 180 degrees the other ways. About 85 per cent of our tours now are with the Biggs killer whales.”
Unlike their endangered cousins, who eat only salmon, the transients dine on pinnipeds — seals and sea lions, a group whose population has surged in recent years.
WATCH: Video captures pod of orcas hunting off Bowen Island
A recent Department of Fisheries and Oceans estimate showed about 105,000 harbour seals on B.C.’s coast. That’s about 10 times the number recorded in the early 1970s.
Researchers with the Vancouver Aquarium say that number reflects a return to the historical average after mass killings in the 20th century, while fishers argue its a population explosion that needs to be culled.
Either way, it’s created ideal conditions for the transients who Birdsall said are not only returning to the inner coast, but are also beginning to gather in larger numbers.
“In the early 1970s we really thought of the transients as travelling in really small groups, often alone, and it was really uncommon to see them in larger groups. And in the last decade or so we’ve started to see transient families get together in these large, large groups,” she said.
WATCH: Bowen Island man describes orca close encounter
One of those larger groups is exactly what one of Pidcock’s boats observed on the Sunshine Coast near Sechelt earlier this month.
“We came across an aggregation of pretty much the largest documented group of Biggs killer whales ever in our waters,” he said.
“We came up with the number of 41 animals. When we used to encounter the Biggs killer whales it would usually be just one family group, anywhere between three to five animals.”
Birdsall said a grouping of transients that big would have been “unheard of” 10 or 15 years ago.
Compared to the Southern Residents, who now number just 74, Ocean Wise estimates there are about 304 inner coast transients and 217 outer coast transients for more than 500 living in the region.
Pidcock said that population is also growing rapidly, with up to 20 new calfs born a year, and 70 new births — nearly the entire population of southern resident orcas — recorded in five years.
“When you spend a lot of time on the water they kind of become your extended family and it’s really wild to look at the images and look at both species and see the difference in their body conditions,” he said.
“The transients are just so robust, and I hate to use the word ‘fat,’ but they’ve got a really great blubber layer, they look really good and when we do see the southern residents its really noticeable the difference in body size and shape.”
But while Birdsall says the transients could be viewed as a success story in terms of their rebound, they remain sensitive to the same stresses as their cousins.
She said their better body conditions mean they are able to better withstand threats like disturbance, noise and pollution — but only so much.
“But we do want to really make sure that just because these animals have plentiful prey, we still need to enact some protections for them.”
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