Biggest Chinook Salmon Haul Going to Sea Lions, Seals & Killer Whales

A young resident killer whale chases a chinook salmon in the Salish Sea near San Juan Island, Washington, in September 2017. Oregon State University, Flickr Creative Commons

It’s been a long haul, but West Coast seal and sea lion populations have recovered over the past 40 years. All those extra predators may be eating more chinook salmon than people are catching, according to a new study.

Increasing numbers of marine predators could be bad news for chinook salmon — and for critically endangered Southern Resident killer whales.

In a new study published in the journal Scientific Reports, researchers used models to estimate how many salmon marine mammals are eating.

“The reality is, if (marine mammal) population numbers are increasing, undoubtedly their consumption and predation is also increasing,” said Brandon Chasco, the study’s lead author and a Ph.D. candidate at Oregon State University.

Turns out, sea lions, harbor seals, and growing populations of killer whales in Alaska and Canada are consuming almost 150 percent more chinook salmon than they did 40 years ago. That’s compared to a 41 percent decrease in the amount of chinook salmon fisheries are harvesting.

“This sort of thing has been documented around the world — recovery of seals and sea lion predation on fish that lots of people care about and harvest,” said Isaac Kaplan, with NOAA Fisheries Northwest Fisheries Science Center and study co-author. “But really putting the diet information together and doing the sort of careful accounting … it really emphasizes the strength of that impact on the chinook salmon population.”

As the juvenile salmon swim out to sea, they get eaten by seals and sea lions. Then some salmon swim clear up the coast to Alaska, where booming populations of killer whales take a bite out of the chinook numbers.

As the salmon then migrate back to spawn in Northwest streams, there are fewer fish for the southern resident killer whales in Washington’s marine waters.

The researchers said all that means chinook salmon could be doing better than previously thought — they’re just getting gobbled up before returning home and getting counted.

“There is a conflict. There is a trade-off here,” Kaplan said. “To some extent, it means that recovery of chinook salmon populations has been more successful than we realized — it’s just that some of that success is going towards feeding marine mammals.”

The sea lions and seals are protected by the U.S. Marine Mammals Protection Act of 1972. At the same time, the Endangered Species Act protects chinook salmon.

Columbia River tribes of Native Americans have recently fought to protect salmon runs from the pinnipeds, asking for authorization to kill more of the sea lions that feast on the fish.

The study, funded by the Pacific Salmon Commission, found that sea lions and seals are eating more individual fish, while killer whales are eating more biomass, or weight, of fish. It’s unclear, right now, which number has a bigger impact on salmon numbers, Chasco said.

The researchers said salmon recovery efforts must take into account all the different challenges salmon face, including these increasing marine mammal predators studied.

Right now many salmon survival models focus more on ocean conditions and commercial and recreational fisheries. Taking more of an ecosystem approach to managing salmon might be a better way to go, the researchers said.

“There’s more than just fishing to the story (of salmon recovery). There’s also predation,” Kaplan said. “This study helps us understand that there are multiple pressures acting on salmon.”

But there’s still much more to study, Chasco said.

For example, he said, “Is this an additive effect, or is it these predators simply taking fish out of the mouths of other predators?”

Originally published: http://www.opb.org/news/article/salmon-haul-seals-sea-lions-killer-whales/

Record Salmon Run Expected

“The Klamath River expects a record chinook salmon run this year, the most since 1978. Much like the abundant forage – such as sardines and squid – that live off California’s coast, the high numbers of salmon reflect both strong precautionary fishery management practices and good ocean conditions.

– California Wetfish Producers Association (CWPA) 

Epic forecast for fall run on Klamath River

Written by Adam Spencer, The Triplicate

The largest projected return of fall-run chinook salmon since 1978 is looming over the Klamath River.

A valley of the Klamath River. Courtesy of U.S. Fish and Wildlife Service

Fishery managers project that roughly 380,000 adult chinook salmon  will migrate up the Klamath this fall to spawn — three times the estimated run of 2011 adult chinook and 50 percent greater than the highest run on record (245,242 total fish in 1995).

Starting Wednesday, sport fishermen will be allowed to keep four adult chinooks per day, with a possession limit of eight adult chinooks.

The abundant forecast is a boon for sport anglers, tribal fishermen and the guides, hotels and restaurants that benefit from tourism dollars.

“I think it’s going to be the best season I’ve ever seen,” said fishing guide Gary Hix, who has already booked up much of his season on the Klamath.

“We haven’t had a four-fish quota since the quota era started,” said Wade Sinnen, senior environmental scientist with the California Department of Fish and Game.

Sinnen said it was a “tough sell” to convince the California Fish and Game Commission to adopt the four-fish limit, but the projections warrant it. “Even with a four-fish adult bag, it’s very unlikely we will obtain our quota,” he said. “This is a test year to evaluate the capacity of the sport fishery.”

It’s important to get as close as possible to the sport-fishing quota of 67,600 chinooks, because conditions are ripe for another event like the 2002 fish kill when tens of thousands of salmon died from diseases before spawning — partly due to more fish than usual.

An estimated 34,000 to 78,000 salmon died primarily from a gill-rotting disease known as “ich” (Ichthyopthirius multifilis).

“I was out there counting those dead fish; it was a smelly, disgusting mess — it was sad really,” Sinnen said. “People are nervous this year that the same thing could occur due to the record forecast of salmon and dry to average water conditions in the Klamath basin.”

To prevent a repeat fish kill, the Bureau of Reclamation started releasing additional water from the Lewiston Dam on the Trinity River to keep the flow of the lower Klamath River at 3,200 cubic feet per second throughout the peak of the fall run.

Mike Belchik, senior fisheries biologist for the Yurok Tribe, presented a case for higher flows for the fall-run chinook to the multi-agency Trinity River Fall Flows Workgroup, which was well received.

Maintaining a minimum flow of 2,800 cfs for an above-average run had already been established, but this run’s bigger than that.

Belchik emphasized to the group that excellent salmon fishing on the ocean provided reason to trust the predictions, and “in order to decrease the odds of fish kill happening we would like to increase the flow from 2,800 to 3,200,” he said.

Read the full article on Triplicate.com.