Stopping chinook fishing might not be enough to feed orcas: salmon expert
‘Everything’s on the table’ to help raise population of southern resident whales
Stopping all fishing of chinook, including harvesting by First Nations, likely won’t provide an instant food solution for endangered southern resident killer whales, the president of the Pacific Salmon Foundation said Tuesday.
Brian Riddell, a former senior official with Fisheries and Oceans Canada, said in an interview there are limited options to help the whales other than to stop salmon fishing.
“Can you do it? Certainly. That’s something that could be done right now, if that was the priority. You could stop all fishing and put all the fish on the spawning grounds,” Riddell said.
“It depends how far you want to take it. These things have repercussions — First Nations use, for example. I think everything’s on the table.”
The Pacific Salmon Commission reports a total catch of 1.69 million chinook in 2016, including 1.15 million by Americans and the rest by Canadian fisheries.
Riddell said he is not convinced that “large-scale immediate actions are going to make an immediate difference” for the whales. He also said it is possible to provide limited in-river First Nations chinook catches without having a major impact on productivity.
In Canada, only conservation takes priority over First Nations’ food, social and ceremonial fishing.
What is needed over the longer term is to increase the overall abundance of chinook, including protection of their habitat, while acknowledging the impact of other marine predators on those same chinook, Riddell said.
“That’s probably the only way we’ll make a significant difference,” he said.
One way to increase productivity is to acclimate chinook smolts through their transition to sea water by feeding them in temporary pens.
Chinook is the largest species of Pacific salmon and the preferred diet of the southern resident killer whales, especially in summer. The fish typically has a five-year life cycle.
“There’s no question the whales are struggling in terms of diet,” Riddell said. “We have to make a major change. If the decision is that southern resident orcas are the priority for recovery, then we’ll have to provide additional food and other actions as well.”
Southern residents are thought to number just 76 in three pods after a young male showing signs of malnutrition disappeared last month. Lack of chinook is thought to be a leading cause of their decline, with other factors including pollution and vessel noise.
Riddell said ongoing research involving the foundation and the University of B.C. shows that harbour seals can have a substantial impact on juvenile chinook migrating downriver to sea and the culling of seal populations may have to be considered at some point. “If you show evidence … I’m quite sure that option is going to be brought up,” he said. “There are a lot of seals around. They’re a significant source of (chinook) mortality.”
Birds are also a significant predator of juvenile fish swimming downstream.
Riddell said that fishing impacts on chinook have already declined by at least 50 per cent in recent decades. The harvest rate on the highly productive Harrison River white chinook population is now below 30 per cent.
“It’s not going to be a single action that’s going to save the whales,” he said. “What is the time frame in people’s minds to accomplish this?
“Something has to change. It’s a matter of how good our data is and what steps can be taken. Invariably, it’s a longer-term goal.”
He added that it also must be established just how many chinook the residents require for their survival.
“If we err on the high side, we’ll have a very significant effect on other uses,” Riddell said.
Mammal-eating transient killer whales have an abundance of prey, especially seals, and continue to increase steadily, numbering close to 300 from Washington to southeast Alaska.
Riddell chaired an invitationonly panel discussion Tuesday in Vancouver on prey availability for southern resident killer whales. A multi-stakeholder symposium on the killer whales continues today and Thursday, but the federal government has banned journalists and the public from attending.
Lara Sloan, a spokeswoman for Fisheries and Oceans Canada, said organizers cited lack of space and a concern that stakeholders would not feel free to speak their minds if reporters are present.
She also insisted “this isn’t a science symposium,” although the official program for the event states that the top objective is to “ensure that all interested parties have a full understanding of the most recent science” on southern resident killer whales.
The symposium is being held as part of the federal government’s oceans protection plan, which was announced last November.