California sea lions late this week were as scarce as spring chinook salmon in the area just below the lower Columbia River's Bonneville Dam after state biologists captured seven of the big creatures and removed five of them.

One was branded, fitted with an acoustic tag for research purposes and released Tuesday. A second California sea lion already carried a brand but did not meet criteria that would allow his removal so was also released.

The remaining five all met criteria and were euthanized as part of an effort by the states of Idaho, Oregon and Washington to remove pinnipeds that are known to have preyed on salmon and steelhead below the dam in the past.

Of the two California sea lions captured and released, one skedaddled and has since been seen more than 140 river miles downriver at Astoria, Ore. The other was the lone California sea lion at the dam at week's end.

The 2010 upriver spring chinook salmon run has yet to make much of a showing. Only 13 have been counted climbing over Bonneville's fish ladders so far this year, including five this week. Observers watched the first salmon "take" of the year this week. Typically the number of California sea lions at the dam begins to grow as more and more spring chinook begin to arrive.

At least 13 different California sea lions have been seen at the dam since observations began in early January with 12 being the largest number on a given day.

Researchers at the dam have since 2002 been charting the activities of the California sea lions and other pinnipeds that have in recent years found easy pickings. The California sea lions focus primarily on salmon and steelhead during their winter-into-spring sojourn while Steller sea lions prefer white sturgeon.

Of the 13 individual California sea lions seen at the dam this year, at least 10 have been seen in previous years and nine are on the list for removal. To date, six of those have been removed.

There have been at least 33 different Steller sea lion spotted at the dam and they are making a dent in the sturgeon population with 911 observed kills. California sea lions have taken three sturgeon to bring the total of 914 through Thursday, according to the U.S. Army Corps of Engineers' week research report. That total is a record for observations dating back to 2005. The previous record was 758 last year.