Hello Tweeters:

Charles Swift wrote:

""".....An article today in the Spokane Spokesman-Review claims 4 - 20 million
(a pretty large margin of error!) smolts per year being taken at the mouth of
the Columbia R. by Caspian
Terns. I'm interested if anybody in tweeterland is aware of this research and
what folks' opinions of it are.""""

An article in the Seattle Times of January 17th of this year had the same
information. It indicates that Oregon State University is the one doing the
research. The full article is listed below and copies can be obtained by
going to the Times home page and doing a search.

Jim Brewster
BrewsPad at aol.com
Kent

Copyright 1998 The Seattle Times Company

Science/Health : Saturday, January 17, 1998

Caspian terns eating millions of salmon heading to ocean

by The Associated Press

CORVALLIS, Ore. - Young salmon that survive their journey down the Columbia
River to the Pacific are being eaten by the millions just a few miles short of
their goal, Oregon State University researchers say.

The smolts are the favorite food of a growing population of Caspian terns on
Rice Island, a two-mile stretch of dredged sand eight miles upstream from
Astoria.

The colony of birds, established 11 years ago, has grown to about 8,000 pairs,
making it the largest colony of Caspian terns in North America and perhaps the
world, wildlife biologist Daniel Roby says.

University researchers Carl Schreck and Larry Davis discovered the birds'
salmon-feeding habit in 1996 as part of a three-year research project into
factors causing stress for salmon migrating to the Pacific.

In 1996 and 1997, the researchers released radio-tagged salmon below
Bonneville Dam and found that terns on Rice Island ate as many as 15 to 20
percent of the smolts - perhaps up to 20 million a season - that reached the
Columbia River estuary. Roby studied the tern colony's diet last summer and
found that it was about 85 percent salmon smolts.


The terns are protected by federal law, but researchers say they could be
encouraged to move elsewhere by building another sand island from dredge
material. Planting vegetation on the island would discourage the terns, which
prefer bare sand.

Research is planned to determine if other birds, such as cormorants in the
estuary or gulls nesting upriver, also pose a threat to the salmon.

There are some signs that nature is solving the tern problem. Very few nesting
pairs of terns produced offspring during the last breeding season, possibly
because of the high river levels, ocean conditions and raids on nests by
predators.

Copyright 1998 The Seattle Times Company