the film

New Bonneville Fish Ladder Barrier
No Match for Determined Sea Lion

by Erik Robinson, staff writer
The Columbian, March 8, 2006

(Dave Olson) Workers using a crane install a temporary steel grate measuring 12 feet wide by 37 feet tall at the opening of one of 12 fish ladders at the foot of Bonneville Dam. The Army Corps of Engineers might have to come up with a new name for the sea lion branded by researchers as "C-404."

Maybe Harry, as in Houdini.

In early February, the corps unveiled a series of steel barricades designed to keep sea lions out of the fish ladders at Bonneville Dam. Officials weren't sure the gates would do much to reduce the bite sea lions are taking out of endangered salmon runs, but they thought they had at least saved themselves from the irritation of watching sea lions cavort within the fish ladders.

They thought wrong.

It took less than a month for this sea lion to make a mockery of man's latest effort to separate salmon-munching pinnipeds from imperiled salmon. As best anyone can figure, the animal managed to squeeze his head through the 151/2-inch gaps in the steel grates and powered his way into fish ladders on both the Washington and Oregon sides. Once ensconced in the ladder, he waits for a veritable buffet of delicious fish to swim his way.

A corps biologist pointed out that C-404 is a particularly pesky creature.

"He is the one that caused all the commotion last year," said Robert Stansell, a fisheries biologist for the corps. "He's just a very inquisitive, adventurous animal and he wants to get in there."

Despite spending more than $1 million building and installing a dozen steel barricades to keep salmon-munching sea lions out of the dam's fish ladders, the wily and apparently limber C-404 managed to breach security over the weekend. Stansell said the California sea lion, which he described as small to medium in size, meaning it probably weighs several hundred pounds, arrived at Bonneville by Feb. 26 in pursuit of the first arrivals of the spring salmon migration.

The barricades were designed to provide gaps big enough to block sea lions while allowing salmon to pass, but the first field test didn't come until C-404 migrated 140 miles up the Columbia River from the Pacific Ocean.

"It's just hard to believe he can go through a 151/2-inch gap," Stansell said. Bonneville observers figured the sea lions gobbled about 3.4 percent of the salmon that arrived at the dam last year.

While that might not sound like much, it's a big increase over the 0.4 percent of the run eaten by sea lions in 2002.

And, in the highly engineered environment of the modern Columbia River, the U.S. government makes major investments for incremental improvements in salmon survival. For example, the corps spent $55 million three years ago building a gigantic concrete chute to carry ocean-bound juvenile salmon around the dam a project expected to boost survival by 1 percent to 3 percent.

Even though many runs of wild salmon are now protected by the Endangered Species Act, sea lions have the Marine Mammal Protection Act in their corner.

Brian Gorman, spokesman for the National Marine Fisheries Service in Seattle, said there is no practical or quick way to target nuisance sea lions such as C-404 under existing federal law. Gorman noted that it took several years before a trio of sea lions ensconced a few years ago at a similar salmon bottleneck, at Ballard Locks on Lake Washington in Seattle, were trapped and hauled away to Sea World in Florida.

Short of lethal force, there is little to be gained by moving sea lions elsewhere.

"It's like moving drug dealers off a street corner," Gorman said. "They just go somewhere else."

Related Pages:
Sea Lions Barred at Dam, BPA Journal, 3/6
Bonneville Dam Now a Gated Community, by Erik Robinson, The Columbian, 2/15/6

Erik Robinson, Staff Writer
New Bonneville Fish Ladder Barrier No Match for Determined Sea Lion
The Columbian, March 8, 2006

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