California sea lions, starving in their rookeries, take heat for salmon losses

Marine mammal rescuers struggle for the third consecutive winter with effects of global warming

ASTORIA, Oregon; SAN FRANCISCO, California––From the Channel Islands to the Farallons, the heart of California sea lion breeding habitat, marine mammal rescuers are struggling for the third consecutive winter to save some of what appears to be fast becoming a lost generation of the species.

Conservationists, paradoxically, including U.S. Representative Kurt Schrader (D-Oregon) and recently retired U.S. Representative Doc Hastings (R-Washington), are agitating to kill more sea lions in the Columbia River estuary, for allegedly consuming too many spawning salmon and steelhead.

Both threats to sea lions appear to result in large part from human-induced global warming, even as many of the same politically conservative voices claiming to support salmon recovery, including Hastings and his hand-picked successor Dan Newhouse (R-Washington), contend that human-induced global warming does not exist.

Weaning failures

Thousands of sea lion pups have starved to death soon after weaning since December 2012. The adult sea lion population has not yet visibly declined, but young sea lions are increasingly unable to feed themselves.

“Scientists say changes in the coastal California current have pushed fish populations farther from the sea lion rookeries in the Channel Islands, where the pups are born around June,” recently summarized Kim Smuga-Otto of the San Jose Mercury-News. “And the diminishing number of sardines and anchovies have forced nursing mothers to switch to [eating] rockfish and squid. These changes are believed to have contributed to a lower quality of milk and higher number of malnourished pups.”

Carrying capacity

California sea lions are considered to be a conservation success story, recovering from just 11,000 at the passage of the Marine Mammal Protection Act in 1972 to a peak population of about 240,000 along the California coast, with about 80,000 along the western shore of Baja California, Mexico, and another 31,400 in the Gulf of California.

Growing at up to 5% per year for decades, the California coastal sea lion population leveled off circa 2000. Since 2008 the Gulf of California population has declined 20% since 2008.

Initially unconcerned, marine mammologists suggested that perhaps California sea lions had just reached the carrying capacity of the habitat.

Now the carrying capacity of the habitat seems to be diminishing. Charged with enforcing the Marine Mammal Protection Act, the National Oceanic & Atmospheric administration became concerned enough about the 2013 starvation of sea lion pups to appoint a committee of scientists to investigate.

El Niño

The committee warned sea lion rescuers to expect more of the same, attributing the decline of carrying capacity to the El Niño weather effect.

Not exclusively an effect of global warming, but closely associated with it, “El Niño brings warm ocean waters that push down nutrient-dense upwellings that fuel ecosystem richness, forcing sea lions to hunt longer distances and do deeper dives for their prey,” explained Orange County Register staff writer Erika I. Ritchie.

“Sea lion mothers––to nourish themselves and provide milk––swim as far as 120 miles north [of the Channel Islands rookeries] toward Monterrey in search of sardines and anchovies,”  Ritchie continued.  “In the El Niño climate, some of these are scarce and they feed on less fatty fish, producing less nutrient-rich milk. The mothers generally spend three to four days hunting,” between nursing sessions with their pups.

“Diminished prey can make them stay out for six days. In their struggle to survive, pups follow older sea lions out into the ocean too early. Those that make it litter Southern California beaches,” where many are found and rescued, but “Thousands more die along the way,”  Ritchie finished.

“Prepare for the worst”

Said National Marine Mammal Laboratory wildlife biologist Sharon Melin, “We’ve told the rescue centers to prepare for the worst.”

“Marine mammal centers in 2013 took in more than 1,500 sea lion pups––five times higher than in a normal year,” wrote Ritchie.

The numbers of rescued sea lions were somewhat less in 2014, as “sea lions produced just half the number of pups following the high death rate” of 2013, Ritchie continued, but “In the first three weeks of 2015, sea lion rescues were up almost 20% over 2013.”

As of January 26, 2015, Ritchie recounted, citing numbers reported by rescue centers to the National Marine Fisheries Service, “Sea World in San Diego had 48 sea lions. The Pacific Marine Mammal Center in Laguna Beach had 28. Fort MacArthur in San Pedro had 73, the Channel Islands Marine & Wildlife Institute had 10, and the Marine Mammal Center in Sausalito had 35.”

Unlike in 2013, “We’re not just seeing little pups,” Marine Mammal Stranding Center veterinarian Lauren Palmer told Ritchie. “Females and yearlings are coming in with respiratory issues and elevated abnormalities in their blood work.”

Of most concern, eight-month-old sea lions are frequently found to have gained only five pounds or less since birth.

The ratio of rescued sea lions to deaths is unknown, but may be anywhere from dozens to hundreds of sea lions lost for every one who is successfully rehabilitated.

“Too many” sea lions on the Columbia

Yet while California sea lions as a species may be approaching a population crash, the recreational and commercial salmon fishing industries believe there are entirely too many California sea lions making their way up the Columbia River estuary, dividing Washington from Oregon, to the waters below the Bonneville hydroelectric dam, 146 miles upstream from the river’s mouth.

The Columbia River estuary is more-or-less where the northernmost range of California sea lions meets the southernmost range of the much larger and scarcer Stellar sea lion, listed as endangered until 2013.

The two sea lion species’ range overlaps throughout the Salish Sea region, including Puget Sound in Washington and the Georgia Strait in British Columbia, and historically overlapped as far south as the Channel Islands, but most of the sea lions venturing into the Columbia River estuary area from either north or south today are vagrant males.

The vagrant males tend to wander away from the rookeries to the ends of their species’ ranges, leaving the more accessible parts of sea lion range to nursing females and young.

Overfished

First formally described as a species in 1828, California sea lions were as early as 1841 observed hunting salmon in the vicinity of the rapids that were submerged by the construction of the first Bonneville dam in 1934.

The pre-settlement salmon and steelhead runs along the Columbia River and tributaries have been estimated at 10 to 16 million fish. But, beginning in 1866, intensive commercial netting rapidly depleted the runs.

Perhaps the primary culprit, opened in 1873, was the J.W. & Vincent Cook Brothers salmon cannery at Clifton, Oregon, closed in 1906.

The first legislation to protect Columbia River salmon took effect in 1908, with the support of then-U.S. President Theodore Roosevelt. Since then, salmon fishing within the Columbia River basin has been restricted to recreational fishers and tribal fishers exercising treaty rights––but the Columbia River runs, along with smaller runs from other Pacific Northwest river systems, have continued to help feed the offshore salmon industry.

The Bonneville dam

If the salmon and steelhead recovered at all, however, the Bonneville dam and 14 other hydroelectric dams built during the next 50 years undid the progress. The largest salmon run on the Columbia since 1938 was just 3.2 million fish. Since 1990, and especially since an unusually poor fishing season in 1994, government agencies have spent an estimated $500 million to $1 billion per year trying to bring the Columbia River salmon runs back from the low hundreds of thousands into the millions of fish annually.

Monitoring sea lion predation on spawning salmon at the Bonneville dam, the U.S. Army Corps of Engineers found that from 2002 through 2013, California sea lions consumed an average of less than 1.7% of the spring run. Sea lion predation, by both Steller and California sea lions, peaked at under 4%.

But spring chinook salmon survival fell from 82% in 2012 to 69% in 2013 and just 55% in 2014. And about 45% of the 2014 spring chinook run disappeared between the Bonneville dam and the mouth of the Columbia, according to the Northwest Power & Conservation Council, an entity created in 1980 by the federal Pacific Northwest Electric Power Planning & Conservation Act. Among the Northwest Power & Conservation Council duties is ensuring that salmon conservation efforts do not conflict with providing electrical power to Oregon, Washington, and Idaho.

More sea lions come north

The decline in spring chinook survival coincided with the rise in sea lion pup starvation off the California coast, and with an increase in the California sea lion population observed by Oregon Department of Fish & Wildlife staff at haul-out sites near Astoria from 72 in 2011 to 616 in 2014.

For whatever reason, more California sea lions appeared to be venturing into the Columbia River estuary in search of a meal––and more Steller sea lions, too. The U.S. Army Corps of Engineers attributed 62% of the sea lion predation on salmon to California sea lions, one third to Stellers.

Fireworks

Blaming sea lions for the failure of salmon to recover, despite the slim likelihood that predation averaging 1.7% of the stock had anything to do with it, the U.S. Army Corps of Engineers and the Oregon and Washington departments of conservation began using fireworks to haze them away from the waters beneath the Bonneville dam in May 2005. Vigilante shootings of sea lions along the Columbia River were first reported in 2007.

The National Marine Fisheries Service authorized killing up to 85 California sea lions in March 2008, but implementation was repeatedly delayed and eventually limited to killing no more than 30 California sea lions per year by litigation led by the Humane Society of the U.S.

Fifty-eight California sea lions were killed and about a dozen relocated to zoos or aquariums through 2014. Stellar sea lions have been hazed but have not yet been subjected to “selective removal,” as culling has been euphemistically called.

Schrader moves to kill more

Hoping to accelerate the pace of culling, Oregon Congressional Representative Kurt Schrader, DVM, in January 2015 introduced the “Endangered Salmon and Fisheries Predation Prevention Act,” a proposed amendment to the Marine Mammal Protection Act which would allow members of Native American tribes to shoot sea lions and harbor seals.

“Before resorting to bullets, the tribal members would first need to make several unsuccessful attempts to move the animals and receive training from the U.S. Fish & Wildlife Service,” wrote Kelly House of the Portland Oregonian. “Currently, the Marine Mammal Protection Act allows only state officials to kill the animals, and only after multiple benchmarks are met.”

The Schrader bill is endorsed by both the Columbia Inter-Tribal Fish Commission and the Coastal Conservation Association, a fishing industry front formed in 1977 as the Gulf Coast Anglers Association.

Sea lion watching

The Sea Lion Defense Brigade and the Sea Shepherd Conservation Society contend that as many as 250,000 people per year visit the Oregon coast to watch California sea lions.  Many of those people,  the  Sea Lion Defense Brigade and the Sea Shepherds say,  eat or stop overnight in Astoria, Newport, and other coastal communities.

This claimed volume of sea lion tourism, if verified, might make sea lions more valuable to the region than salmon fishing. But the weight of history, legislation, litigation, and investment all favors the salmon.

Caspian terns blamed,  too

Sea lions are scarcely the only species blamed for the non-recovery of Columbia River salmon and steelhead. The U.S. Army Corps of Engineers, U.S. Fish & Wildlife Service, and Bureau of Reclamation have been trying since 1999 to break up and disperse the world’s largest colony of Caspian terms, after finding in 1998 that they might have consumed 11 million of the 95 million salmon and steelhead smolts who reached the Columbia River estuary.

The estimated 9,175 mating pairs of terns as of 2005 were about 70% of the entire west coast population.

Luring the terns from Rice Island to East Sand Island, farther from the channels favored by salmon and steelhead smolts, cut the terns’ estimated salmon and steelhead smolt consumption to about 4.5 million. Instead, the terns preyed more heavily on oceanic fish, including herring, anchovy, shiner perch, and sculpins.

The agencies then began dredging to reduce the size of East Sand Island, hoping to encourage dislocated Caspian terns to establish new nesting colonies as far south as San Francisco Bay.

Poop analysis

But dispersing the terns from Rice Island and East Sand Island also sent more terns up the Columbia to Goose Island and Crescent Island, far upstream.

Based on poop analysis, “From 2007-09 about 370 pairs of terns nesting on Goose Island feasted on 14.6% of inland Columbia Basin steelhead,” summarized Annette Cary of the Kennewick Tri-City Herald in February 2014. “In 2004, about 530 pairs of nesting terns on Crescent Island are estimated to have eaten 22% of the Snake River steelhead. The tern population there has since dropped to about 420 pairs. The birds also eat juvenile chinook and sockeye salmon.”

Double-crested cormorants

Meanwhile, evicting Caspian terns from East Sand Island also opened more habitat to double-crested cormorants. From 100 nesting pairs in 1989, the double-crested cormorant population grew to 13,000 nesting pairs, currently blamed for eating 11 million salmon and steelhead smolts per year––the same number the terns allegedly consumed 17 years earlier.

Proposing in mid-2014 to kill 16,000 double-crested cormorants, the U.S. Army Corps of Engineers on February 6, 2014 issued a final environmental impact statement “in response to more than 152,000 public comments on the original plan, nearly all of which expressed opposition to the killing,” reported House of the Oregonian.

“The revised version,” House continued, “calls for shooting nearly 11,000 birds by the end of 2018 and pouring oil over 26,000 nests to prevent eggs from hatching. The Corps’ goal is to reduce the colony by 57%, to about 5,600 breeding pairs.”

“Absolutely horrific”

Objected Portland Audubon Society conservation director Bob Salinger, “We’re talking about killing 15% of the cormorant population west of the Rocky Mountains. That level of lethal control is absolutely horrific.

“What we are seeing,” Salinger told media, “is a wider and wider net being cast to manipulate a variety of species––cormorants, gulls, Caspian terns, sea lions––natural predators that have coexisted for millennia with salmon. In the meantime, we don’t feel the core reasons for salmon declining have been adequately addressed by the Corps––the dams.”

But even if all 14 hydroelectric dams along the Columbia and major tributaries were removed tomorrow, salmon and steelhead likely would not return to runs in the multi-millions.

Global warming

Expected to reduce precipitation over much of the Pacific Northwest, global warming in the coming decades is expected to cut the water flow in some spawning streams to the point that salmon and steelhead can no longer use them. Lower water levels in other streams will expose more eggs, smolts, and adult fish to predators ranging from minnows to birds and bears.

Dams or no dams, the Pacific Northwest habitat has already irrevocably changed. And nature will probably better accommodate the changes than human culture, economic interests, and politics.

(See also The Double-Crested Cormorant:  Plight of a Feathered Pariah.)

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