Dolphins delight with return to B.C. waters, but some see 'invasive species'

After 100 years of absence, large numbers of Pacific white-sided dolphins are back in the northern part of British Columbia's Salish Sea.

But while their return is being greeted by some with delight, the head of a commercial fisheries group is dismayed by the appearance of what he calls an “invasive species,” alongside increasing numbers of seals and sea lions.

Simone Thom, a BC Ferries catering worker, said she was thrilled to see a superpod of hundreds of Pacific white-sided dolphins, frolicking in the wake of a ferry from Comox to Powell River last month.

Thom's video of the “exhilarating” encounter went viral on social media.

“It (was) truly magical to see them in their natural state doing their ballet,” said Thom. “I've lived here on the island pretty much my whole life and I've never seen this.”

So many dolphins in that particular area is rare, said Professor Andrew Trites, director of the Marine Mammal Research Unit at the University of British Columbia.

Although there are estimated to be one million Pacific white-sided dolphins, they are usually found in the open ocean.

Small numbers began to visit the Georgia Strait in the early 2000s, with about 100 to 200 eventually taking up residence in the Salish Sea, Trites said.

“We know they were here in the past,” Trites said.

Their remains have been found in First Nations middens going back 2,000 years, but they all but disappeared for 100 years, he added.

“So that's a strange thing, like where did they go and what brought them back?”

Their return coincides with an increase in the number of seals, sea lions and transient killer whales that prey upon marine mammals.

Trites said one possible explanation was that through complex food web interactions, the increase in the number of seals may lead to more young herring for dolphins to feed on.

“Before this time, we had heavy culling of seals. There was whaling. We've come through a period of removing marine mammals and trying to control nature. And now, since they've been protected, I think the ecosystem is re-establishing itself and re-establishing a natural balance which is healthier overall.”

Others vehemently disagree.

“These dolphins are here because the balance in the waters is off,” said Tom Sewid, a commercial fisherman from Kwakwaka'wakw First Nation. He said the dolphins are “an invasive species” driven into new waters by driftnet fleets.

As for the increasing number of seals and sea lions over the past fifty years, Sewid said it was another example of how the ocean is out of balance.

“We've forgotten our Indigenous ways of harvesting seals and sea lions, and in those areas, we're seeing a great overpopulation,” he said, adding that he believed overpopulation of seals and sea lions was a major contributor to the depletion of salmon stocks.

Sewid is the president of Pacific Balance Marine Management, an organization seeking to protect salmon and other fin fish stocks from being “eaten into extinction,” by redeveloping a First Nations-led commercial seal and sea lion harvest.

He said a series of fisheries ministers had “basically ignored” their requests.

Sewid said he addressed federal Fisheries Minister Joyce Murray at last month's first-ever Seal Summit, a two-day conference for stakeholders in the seal industry.

“I said, 'Come hell or high water, coastal First Nations and river First Nations of British Columbia, we will get a licence to sell our seal and sea lion products,'” he said. He said he would take the issue to the courts if necessary.

B.C. First Nations are currently allowed to harvest seals and sea lions for food, social and ceremonial purposes. Sewid says permitting the sale of fur, omega-3 supplements, meat and other products would create 4,000 jobs and allow fin fish populations to recover.

In the past three years, Pacific Balance Marine Management has provided gift cards to First Nations harvesters to purchase bullets.

Sewid estimated that thousands of seals have been removed for food, social and ceremonial purposes from rivers, lakes and estuaries. He said salmon numbers were increasing in some systems as a result.

Stomach samples were being taken for research purposes, and meat and blubber testing for toxins.

Sewid said he would submit a harvest proposal to Murray, and wants a quota set for seals and seal lions.

He estimates an annual harvest of 5,000 to 10,000 seals would be sustainable. According to Fisheries an Oceans research documents, there are approximately 40,000 sea lions and 105,000 seals in all of B.C.

Carl Walters, professor emeritus at the University of British Columbia's Institute for the Oceans and Fisheries, sees the potential for a substantial First Nations-led seal and sea lion harvest based on historical data and modelling predictions. He presented his findings in early December to the Senate committee on fisheries and oceans.

“It's wrong to think things are coming into balance. OK, even if they are, why do we have to accept that kind of balance? Why do we have to accept a balance that has a top-heavy food web with a really large number of ugly, nasty blubberballs hauled out on the rocks?” he asked.

He said a 50 per cent reduction of the seal and sea lion population over two to three years would yield the maximum sustainable yield of seals and sea lions, while rebuilding the Georgia Strait salmon fishery to about half what it was at its peak in the 1980s.

“If it was up to me, we'd knock them down to about 20 per cent of their current level. We'd accept a lower harvest for that population, because the benefits to the fishery would be so much larger.”

He said there's no doubt that seals and sea lions are consuming salmon, but it's not clear if they are actually eating “dead fish swimming” - older or diseased fish that were about to die anyway.

The only way to know for sure, he said, would be to conduct a large-scale experiment to reduce the population by half, and assess the impact on salmon stocks over 10 years.

He said he was “completely confident that there will not be a big food web effect.”

“We had a 60-year period from 1920 to 1980 where seal populations were low in the Georgia Strait,” he said. “We had a huge long experiment if you like, and nothing went wrong in the ecosystem … In a way, we'd be returning the system to the state that showed really high productivity. It's a no-brainer.”

But Trites warned that such an experiment would be a “huge gamble.”

“The risk of running such an experiment is that you're playing with life.”

Trites said seal and sea lions numbers had been stable for 25 years, something inconsistent with overpopulation or a population out of balance. Present numbers were similar to what they were in the 1880s, when Europeans first arrived, he said.

“I don't see any evidence that if the seals are removed, you're going to see more salmon,” he said.

Researchers had found that juvenile salmon were dying in the open ocean at higher rates.

“The seals are not in the open ocean,” Trites said. “Something else is out there.”

He said there was “generational difference in values” regarding attitudes toward seal and sea lions.

“Those that grew up in the '50s and '60s saw a world where man dominated and we removed the marine mammals and that was just fine,” he said.

“What I see with the current generation of young scientists is they're concerned about conservation. They're concerned about keeping ecosystems healthy, and it's not about resource extraction … In the end, it's just a difference of values.”

In a written response to questions, the Fisheries Department said it worked with First Nations on plans to harvest small amounts of seals and sea lions for food, social and ceremonial purposes.

It confirmed it had received a few proposals for a commercial seal and sea lion harvest. A review is typically a multi-year process taking into account ecosystems, biodiversity and harvest methods, it said.

“Commercial fisheries are not to be used as a tool to control populations,” the department said. “There is a high degree of scientific uncertainty regarding the extent of pinniped 1/8 seal and sea lion 3/8 predation on wild fish stocks.”

This report by The Canadian Press was first published Dec. 25, 2022.

Liana Hwang is a family physician in Alberta with a science degree from the University of British Columbia, and a fellow in Global Journalism at the University of Toronto.