Saturday, September 18, 2021
Sept. 18, 2021

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Record heat, drought threaten L25, the oldest orca — and the winter Chinook she depends on

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She is still out there: L25, the oldest of the orca matriarchs, leaders of the southern resident J, K and L pods.

L25 was most recently photographed June 7 on the west end of the Strait of Juan de Fuca, at Swiftsure Bank.

“It was exciting to see her again,” said Mark Malleson, who photographed her for the Center for Whale Research. He knows L25 at a glance, from 25 years of photo-identification work for the center.

“She is a beautiful animal, she is unmistakable, she has a pretty large dorsal and a distinct saddle patch,” he said referring to the white markings on either side of an orca’s dorsal fin.

“Every year, it is, ‘Is she still alive?’ “ Malleson said. “She has been around a long time.”

No one really knows when she was born, but if her estimated birth year of 1928 is correct or even close, L25 has been traveling the seas of our region over uncounted miles for some 93 years.

And this year, with its record heat and drought, is testing even the toughest survivors, including winter-run Chinook that L25 and her family still travel all the way to the coast of Central California to hunt. These succulent salmon once were a staple of the southern residents’ diet, the prize of the Sacramento River system, once second only to the Columbia River in the Lower 48 as a salmon producer.

Both southern resident orcas and the Chinook they primarily depend on are in a fight for their lives as environmental conditions turn increasingly hostile. Chinook, with few exceptions, are in trouble throughout their range.

The southern residents are often thought of as a Puget Sound whale because of J Pod, which of the three pods is the most frequently seen there. But the southern residents actually hunt Chinook over a vast area — and truly live up to their name. A recent paper documented that the southern residents take Chinook from the Taku River in Alaska to the Snake River in Washington to the Sacramento. The Columbia was by far the most important source.

The southern residents are an endangered predator seeking increasingly endangered prey, and climate change is raising the stakes for both species. Today, California winter-run Chinook number only in the thousands — in a good year. Mortality rates for eggs from this year’s spawning run are estimated at nearly 90% because of high water temperatures.

The entwined stories of winter-run Chinook and L25 illustrate the larger web of life that salmon weave, noted Rachel Johnson, biologist at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center.

Salmon don’t make up a monolithic block, but are a mosaic of populations, particular to their place, each convolved with certain environmental conditions and with other species they support.

“Their behaviors, and how and where they aggregate, the timing of their migration — are cues for animals looking to eat them,” Johnson said.

In this way, the decline of the orcas, hunting Chinook heading back to the Snake, Columbia and Sacramento rivers, is connected.

L25 was photographed with her family off Monterey Bay in the spring of 2019, and it’s likely she continues to forage there for Chinook — like her mother, and her mother before her.

Warming waters

Historically, winter-run Chinook spawned in cold mountain streams. But construction of Shasta Dam without fish passage confines them to spawning in the baking-hot Central Valley floor, in the main stem of the Sacramento River below the dam.

Dam operators release precious water during the spawning run from deep in the reservoir, effectively trying to make as least part of the river function like the cold mountain streams that allowed these endangered Chinook, the only summer-spawning Chinook in the world, to thrive.

During the peak of their run this summer, the fish are confronting water so hot, they are acting strangely, bumping into boats, covered with fungus and even dying before they spawn, reports Doug Killam, senior environmental scientist with the California Department of Fish and Wildlife. Efforts to understand why are ongoing, but high water temperatures are a likely culprit, Killam said.

Usually the Bureau of Reclamation operates Shasta Dam to maintain a pool of cold water, for winter-run Chinook, stretching some 60 miles downstream from the base of the dam.

But this year, the river system is so stressed by competing uses, heat and drought that the cold-water pool will shrink to just 5 miles by the end of the season, Killam said. “When the cold water is used up and the river heats up above 62 degrees, any eggs in the gravel at that point are basically toast.

“It’s depressing for all of us,” Killam said.

Efforts, years in the making, to relocate the fish to their historic habitat in the cold waters of the McCloud River above the dam were aborted by the Trump administration and have yet to be restarted, said Jonathan Ambrose, relocation coordinator for the National Marine Fisheries Service in its Central Valley office, in Sacramento.

Support for the run from a conservation hatchery and relocation efforts in Battle Creek have shown what the winter run can do when given the chance. Fish surprised scientists by returning in bigger numbers to Battle Creek than expected, after a trial release of surplus hatchery fish to the creek. Overall numbers of winter run also ticked up after welcomed rains in 2018 and 2019.

But then came two more years of severe drought.

Fish are routinely transported by truck in Washington to work around lack of fish passage at dams, or to help them survive hostile conditions. Fish managers, once again, are getting ready right now to rescue sockeye from hot water in the Lower Snake River, trucking them their last miles to an inland hatchery. The main stem Columbia and Lower Snake, impounded by eight dams, routinely reach water levels too hot for salmon in summer and temperatures could be lethal this year.

But in California’s Central Valley — one of the world’s most-altered river systems — the idea of transport is often criticized as “unnatural,” Ambrose said.

L25’s unmatched knowledge

Chrome-bright and full of fat, winter-run Chinook were always a prize catch, for southern resident orcas and anglers alike. A 1903 edition of Sunset magazine reports on the joy of salmon fishing in Monterey Bay — and the fisherman’s alarm at the sight of black orca fins slashing through the water. Could it have been L25’s mother and her kin?

Orcas have long ecological memories and deeply imbued cultural practices. They pass on teachings, dialects and hunting skills generation to generation.

Ambrose said he can’t help empathizing with an orca like L25: “You think about these long-lived animals and what must be going through their head. These fish are supposed to be there and not understanding why they are not.”

L25 already has endured and survived so much, including the capture era in the 1970s, when orcas were rounded up and taken from their families and shipped around the world to aquariums. All the southern residents taken during that time — a third of the pods — are dead today but one. Lolita, still alive after more than 50 years of captivity at the Miami Seaquarium. She makes L pod calls. Is she L25’s daughter?

L25 was born before any of the vast environmental change she now confronts: before construction of the Columbia or Snake River dams, before Shasta Dam, and back when the population of Washington was just over 1 million people. Over her long life, L25 has also had to cope with a steady decline in both the number and size of Chinook salmon.

“She has to work extra hard; it’s kind of sad,” Malleson said. Especially when fish are scarce, the pods depend on the matriarchs to lead them to fish. After L25’s passing, there will be no one with her depth of knowledge. The next orca in line is some 40 years younger.

“She has seen it all, I can’t even imagine all she has seen,” Malleson said. “It must be disheartening for them, ‘Let’s try here, it should be good, keep looking.’

“She is a pretty good forager, she can dive down for a long time pretty easily, she has always looked like a solid whale. She is a big, old gal.”

On the rare occasions when the J, K, and L pods all come together, Ken Balcomb, founding director of the Center for Whale Research, said he always sees L25 gathering with the older matriarchs.

“She is definitely part of the grandmother group, the senior females gather together, they exchange stories about where they have been and how their families are doing; they get together for days, it is a peer-to-peer kind of gathering.”

If L25 could tell her story directly, “it would be quite a trip, it would be mostly about swimming here, then swimming there,” Balcomb said. “Looking.”

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