March 02, 2007  Fish and Wildlife Columbia Basin Bulletin

The bullets -- in this case rubber -- began flying Thursday in what is the earliest and most ambitious attempt to disturb the eating habits of California and stellar sea lions in the area below the Columbia River's Bonneville Dam.

"This is going to be more intense that last year," the U.S. Army Corps of Engineers' Bernard Klatte told the Technical Management Team Wednesday. The multi-entity "hazing" effort below Bonneville began Thursday and will continue through the end of May, seven days a week during the daylight hours.

"This is considered a maximum effort where we'll likely be hazing from dawn to dusk" throughout the spring chinook salmon migration, and sea lion residency, in the river, according to Robert Stansell, the Corps' leader for research at the dam that has for the past six years evaluated sea lion predation's impact on the salmon runs. Two of the upriver stocks, Upper Columbia spring and Snake River spring/summer chinook, are listed under the Endangered Act.

Those impacts have been judged severe enough that states of Idaho, Oregon and Washington late last year applied to the federal government for permission to lethally remove some of the California sea lions, which are protected under the Marine Mammal Protection Act. The stellar sea lions are ESA listed.

But even if permission is gained, it is not likely to come within the next two or three years. So efforts to make the pinnipeds uneasy and/or chase them away will be stepped up this year. The sea lions have for the past several years gathered at the base of the dam in springtime to feast on spawning chinook salmon that come looking for fish ladders to continue their journey.

Historically few of the marine mammals swam the 140 miles upstream. But, coincident with the new millenium's increase in salmon numbers, more and more pinnipeds have found their way to the dam each year. They are also arriving earlier, and staying longer as years go by.

The Corps researchers estimate that the sea lions' predation on salmon has also increased, from 0.35 percent of the total upriver spring chinook run in 2001 (1,010 salmonids) to 3.4 percent or 2,920 salmon in 2005. Last year the lions consumed an estimated 2.8 percent of the upriver run in the area immediately below the dam.

Observers this year noted the presence of both sea lion species at the dam in mid-January. The stellars have appeared that early before, but it is by far the earliest California sea lion arrival, Stansell said. In 2002, the first California sea lion sighting was later in March and each year that date has slid back farther on the calendar. Last year the first was seen in early March.

"They're eating steelhead so far," as well as lamprey, Stansell said of the California sea lions. The upriver spring chinook run has not yet begun to flow with only one counted passing Bonneville to-date. The first chinook taking by the pinnipeds was witnessed Monday, a day in which seven stellar and seven California sea lions were sighted at the dam. In past years as many as 100 individual California sea lions have made their way upriver eventually. The spring chinook run normally peaks in late April.

The large stellar sea lions last year focused on white sturgeon. They were observed killing 276 of the big fish in the area immediately below the dam.

This year already the stellar sea lions have been seen taking "over 300 sturgeon" of all sizes in the dam's tailrace, Stansell said. He said he did not expect that number to swell greatly. Last year, as soon as the hazing began the shyer stellar sea lions left the area, while the recalcitrant California pinnipeds were little deterred.

"I think we're going to see a reduction" in predation on white sturgeon immediately below the dam, Stansell said, with the stellars moving downstream. Some hazing of the big creatures will likely continue downstream, where fishery officials are on the river conducting white sturgeon surveys.

State officials are very concerned about the potential effects of sea lion predation on white sturgeon, according to Charlie Corrarino, the ODFW Conservation and Recovery Program manager. Many of the stellar targets are mature females, 30 years old or older. So they are not quickly replaced.

"They're often eating the cream of the crop," he said.

In 2005 a first hazing effort was launched but spanned only four days. Last year, efforts were increased in an attempt to evaluate hazing's effects on the pinnipeds' behavior. The evaluation was carried out in four-day blocks -- two days with hazing and two days without -- from March 5 through May 27 with a total of 42 days of hazing. Verbal and physical hazing, rubber bullets and buckshot, cracker shells, seal bombs, and other tactics were used from the dam itself and from boats downstream of the boat restricted zone immediately below the dam. Acoustic deterrence devices were also used.

A task force that will be formed to recommend whether or not the state should get permission to lethally remove individual sea lions will review what tactics have been used in the past to deter the sea lions, Corrarino said.

It will ask "what have the states done already?" Corrarino said. So the maximum hazing effort will employ all legal means to disrupt the plundering of chinook and sturgeon.

The results showed that the hazing made little difference in the California sea lions' salmon consumption. Most that were stirred by the hazing returned almost immediately.

So the effort will be intensified. U.S. Department of Agriculture Wildlife Services agents will work from the dams, and the Oregon and Washington fish and wildlife agencies and state police and Columbia River Inter-Tribal Fish Commission biologists, and others, will work from boats for about 10 miles downstream. They will this year be allowed to haze in the boat restricted zone for the first time. The sea lions last year found safe haven in the zone, only to quickly return to the dam when the hazers backs were turned.

Corrarino said that the law also allows the use of non lethal deterrents by certain groups of people (sport anglers, commercial fishermen, marina operators, etc.) in specific situations. Private individuals can deter marine mammals from damaging private property, including fishing gear and catch, so long as the methods used do not result in the death or serious injury of an animal.

NOAA Fisheries, charged by the MMPA with protecting the pinnipeds, last May issued a draft list of legal hazing methods for California sea lions and Pacific harbor seals. That list can be found at http://www.nwr.noaa.gov/Marine-Mammals/Seals-and-Sea-Lions/Deterring-Pinnipeds.cfm

Any hazing must be consistent with local ordinances, Corrarino said. Seal bombs and cracker shells, as an example, may require a permit. And, it may be illegal to discharge a firearm in certain areas.

Fishermen can only use the non-lethal deterrents when actively fishing with gear in the water. Fishermen must be able to distinguish among the different species of marine mammals because the deterrents are for Pacific harbor seals and California sea lions, not Steller sea lions which are ESA listed.

Sea Lion Exclusion Devices – huge grates that allow fish passage but don't allow the pinnipeds in – have already been installed at nearly all of the dam's 12 fish ladder entrances, Stansell said. The SLEDS were built and first installed last year the sea lions were seen climbing all the way up the ladders.