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Ecology and salmon related articles

Three Little Pigs Could Save the Salmon

by Mike Stahlberg
The Register-Guard, April 1, 2008

April Fool's Day it is, so beware of predatory pranksters.

Here in the Outdoors section, however, there's no space for such nonsense. We'll focus on news of real predators - like wolves, bears, smolt-eating birds and three little pigs.

Given that Tax Day looms and folks are thinking like accountants anyway, we'll look at predators by the numbers.

Four: The number of breeding pairs of wolves that must be documented in Oregon over three consecutive years before wolves are no longer protected by the state Endangered Species Act.

So far there are no documented breeding pairs here, although the presence of one radio-collared gray wolf was confirmed in northeast Oregon in January, and credible public reports of wolf sightings continue, according to ODFW biologists.

The U.S. Fish and Wildlife Service on Friday officially removed the northern Rocky Mountain gray wolf from the federal list of endangered species in an area that includes all of Montana, Idaho and Wyoming, plus the eastern third of Washington and Oregon, and a small corner of north-central Utah.

According to the USFWS, there are more than 1,500 wolves and at least 100 breeding pairs in Montana, Idaho and Wyoming.

So the states now assume full management authority for the continued conservation of the gray wolf.

In Oregon's case, that means wolves will still be considered endangered until the aforementioned four or more breeding pairs are established.

????: The number of bears in Oregon remains something of a mystery, which is why the Oregon Department of Fish & Wildlife is requiring successful hunters to "check-in" their bears at ODFW offices within 10 days of harvest.

Spring bear hunts begin today in parts of western Oregon and the western Blue Mountains, and ODFW biologists want to pull a tooth from every bear harvested. The teeth will be checked for tetracycline, an antibiotic that leaves a permanent stain visible under UV light on the teeth of bears that ate treated baits placed in the wild.

The ODFW knows how many bears ate bait, and ratio of unmarked to marked teeth obtained from harvested bears will allow researchers to calculate the size of the bear population.

Bear check-ins were made mandatory, incidentally, because getting hunters to do so voluntarily turned out to be like pulling teeth.

10,300,000: The number of juvenile salmon and steelhead eaten by cormorants on the Columbia River in 2006, according to an Oregon State University researcher.

(Birds may not meet the classic definition of "predator," but tell that to all the Pacific salmon fishermen who'll be staying ashore this summer.)

In any event, researcher Dan Roby says cormorants have replaced Caspian terns as champion consumers of young Columbia Basin salmonids migrating toward the Pacific Ocean. An estimated 13,700 breeding pairs nested on East Sand Island in the Columbia estuary in 2007.

Meanwhile, about 9,900 nesting pairs of terns gobbled up "only" 5.5 million smolts, according to a summary of the research published by the Columbia Basin Bulletin.

Between them, the two species of birds wiped out about 20 percent of the smolts.

The predation estimates "were developed through visual identification of the prey birds brought to their nests, stomach content analysis and through the retrieval of tags inserted in fish upstream as part of other research efforts," the report said.

Cormorants are four times the size of terns, and better at catching smolts.

"Cormorants continue to be an increasing threat to salmon survival," said Ken Collis, a consultant to the OSU researchers.

Nearly half of the entire West Coast population of double crested cormorant nested on East Sand Island last year.

Wildlife officials are working on a plan to encourage terns to nest along other waterways where they could feed on fish species other than salmon and steelhead. So far, however, cormorant are not responding to those tactics.

Both species of seabirds are federally protected, and both have few natural enemies (although gulls and crows occasionally eat their eggs).

Fishermen, of course, are fast becoming enemies of the birds, and anglers are believed to be behind our final predator tally of the day.

Three: the number of little pigs, weighing 30 to 50 pounds each, that ate all 2,500 eggs laid by cormorants nesting on Snake Island in north Lake Michigan last year.

"Whoever placed the pigs on the island lovingly built a shelter for them, a little lean-to to protect them from the wind and rain," according to a story published in the Nov. 15 Detroit News.

"The state wonders whether a fisherman was behind the releasing of the swine," the story said. "Anglers hate cormorants because they believe the birds feast on the fish they're trying to catch - yellow perch and smallmouth bass."

On other islands in the Great Lakes "people have used raccoons to kill the birds," a state biologists told the paper.

A vigilante-style swine solution for East Sand Island would be illegal, and I'm certainly not suggesting that.

But I am intrigued by this statement that appeared in The Detroit News report:

"The U.S. Department of Agriculture's Wildlife Services limits the cormorant population, which has surged in the past decade, by regularly shooting adults and coating eggs with vegetable oil that kills embryos."

If the Feds can control predatory birds eating bass and perch in the Great Lakes, why not in the Columbia River, where terns and cormorants are impacting 13 stocks of fish listed under the Endangered Species Act?

Mike Stahlberg
Three Little Pigs Could Save the Salmon
The Register-Guard, April 1, 2008

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