[5] Mysterious Sea Lion Deaths Haunt Salmon Run

The late spring chinook run in the Columbia River is finally beginning to run after all.

By the middle of last week, more than 3,000 fish were passing Bonneville dam each day. On April 30, more than 6,000 springers cleared the dam. On May 3, the number jumped to 10,000. And along with the salmon, more sea lions than ever have shown up to feast on the run.

Some have been trapped and hauled away, but that has stopped after six of them were found dead last Sunday in cages below the dam. First reports indicated they had been shot, but NOAA Fisheries announced May 7 that no evidence of gunshot wounds had been found when the animals were examined.

According to a statement released by the federal agency, "An x-ray examination conducted yesterday identified metal fragments in soft tissue around the neck area of two of the animals. In addition, a metal slug was found in the blubber of one animal. However, neither the fragments nor the slug appear to have caused death, and may have been associated with old wounds.

"The agency said it would continue its investigation to determine how the animals died and how the doors to the traps on which they were found could have been closed. Anyone with information that may assist in this investigation is asked to call the NOAA Enforcement Hotline at 1-800-853-1964."

Only one of the six had been identified as a salmon predator, another two were Stellar sea lions, a species listed for protection under the ESA, and who favor sturgeon over salmon. There is some speculation that the animals died from dehydration.

After getting federal approval, fish managers were prepared to use lethal means to keep some California sea lions from doing any more damage to the run. But a district court decision that allowed states to lethally remove some of the pesky salmon predators was blocked when the 9th Circuit Court issued an emergency order that called for the animals to be trapped and hauled away.

A three-judge Niners' panel sided with the Humane Society, who argued that the expected take of listed spring chinook would not do irreparable harm to the salmon run. Federal biologists say sea lions ate more than 4 percent of last year's spring run--about 3,000 salmon.

However, the court said the sea lions could still be trapped and moved to aquariums, while the federal district court in Oregon decides the fate of the sea lions. Oral arguments are scheduled for May 8.

Unfortunately, one sea lion had already died last week after being moved to the Point Defiance Zoo in Tacoma, beginning an outcry from the Humane Society calling for trapping to end, as well. On May 5, Washington and Oregon wildlife managers suspended the trapping effort until further notice.

On April 24, seven sea lions were trapped, including two Stellars, which were released. Several had previously been branded and were trucked to the Tacoma zoo, where they were being held for transfer to Sea World Orlando. The others were driven downriver to Astoria and released.

One of the captured sea lions, branded as C319, has been seen at the dam every spring since 2002, and has even gained another 85 pounds since weighing in last year at 1,151 lbs.

The sea lion that died at the zoo while under anesthesia for a physical exam weighed in at 1,451 pounds. Biologists speculate that its weight problem had something to do with its death. It had been captured April 28.

According to the Corps of Engineers' April 30 report on pinniped predation, 63 California sea lions had appeared at the dam by April 16, nine more than the previous one-day record from last year. More than 30 of the 60 animals already listed for potential lethal take have been back this year--with an additional five animals added to the list of incorrigibles, those who are not fazed by hazing efforts, which have been considerable.

The report says USDA personnel have used 4,000 cracker shells from shotguns, 1,500 shells from pistols and 800 bean bags in their effort to deter predation on the spring chinook run. Other devices to keep sea lions out of fishways have also been deployed and noise abatement techniques began way back in January.

The Corps admits the fusillade has been only partly successful, and that some mammals are not leaving the buffet area, even after multiple cracker shells or rubber bullets.

Corps biologists estimate that predation by sea lions is similar to last year--so far, about 2,400 salmon, 270 steelhead, and more than 600 sturgeon have been observed to have been taken. They say Stellar sea lions are back in the area as well, and have been seen stealing salmon from California sea lions.

By April 30, only about 40,000 chinook had been counted at Bonneville Dam. But daily numbers were still rising, which encouraged biologists who have predicted a spring run of nearly 270,000 fish. Sport and recreational fishermen had caught about 28,000 hatchery spring chinook below the dam before their fishing was curtailed.

On April 29, Columbia Basin managers met to gage the run size. They felt the upriver spring run is likely to come in short of expectations, more like 200,000 or so, but they didn't believe the run was 50-percent complete by the end of the month, which they noted makes run size projections difficult. By May 6, the Bonneville count was about 68,000 springers.

They also noted that river conditions are not very favorable for fish migration, but the high catch-per-unit-effort in the lower-river fisheries has shown abundant numbers. They made no official statement on any change from their preseason estimate. -B. R.

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