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Economic and dam related articles

Salmon vs. Predators

by Carlisle Harrison
Capital Press, April 29, 2005

Recent articles in the mainstream press list numerous reasons for diminishing salmon stocks, but little is said about one of the major causes - predators. As a biology major in May 1955 I had the occasion to take a field trip from Garabaldi, Ore., to Astoria, Ore. This anecdotal account might be dismissed by some but I believe a check of population records would verify what we observed.

From dawn to dark we looked for but saw no sea lions or seals. We were with instructors who knew where to look and we were biology students who knew what to look for. We were not surprised because it was believed that fewer than 2,000 sea lions existed on the West Coast at that time; 300,000 in the same area now is a recipe for disaster.

I don't know how many seals scientists thought there were at that time, but it was considerably fewer than exist today.

On this trip our professor became excited when he observed a Caspian Tern catching a smolt. He instructed those of us who were making a bird list that we should get that one on our list because we were not likely to see another. How wrong he was considering there are now thousands of these salmon predators the full length of the Columbia.

Having grown up on a salmon hatchery in the Columbia Gorge my father would frequently point out fish predators. Before this trip I could recall having seen one cormorant in my life. On this trip we saw cormorants, but they were not on every piling and rock outcropping in the river as we see now.

Last summer I witnessed how adaptable sea lions can be. In the past when a sea lion showed up you had better get your hooked salmon on board quickly or you might end up with half a fish. On two separate occasions we had a sea lion approach our boat only to have them watch until we released the exhausted wild fish. An easy meal.

Over the past 50 years fishing has been curtailed, dams have been adapted to improve fish passage, stream habitat has been improved, irrigators have given up water to enhance stream flows, logging practices have been modified while predator populations have exploded. During this time we have seen fish populations decrease in most salmon streams regardless of whether or not there were dams, irrigators or all the other human "evil-doers." Go figure.

From Center for Columbia River History

Related Pages:
Fish Haven't Been Fighting Structures for 60 Years by Gordon Macdougall, Seattle Post-Intelligencer - 6/9/5

Carlisle Harrison, Hermiston, Ore.
Salmon vs. Predators
Capital Press, April 29, 2005

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