The Washington Fish and Wildlife Commission agreed on another cut to sturgeon catch limits on Friday, capping the annual catch at 17,000 fish for sport and commercial boats below Bonneville Dam for 2011-13. As Allen Thomas at The Columbian reports, that’s down from a limit of 24,000 last year – which was already the result of a 40 percent reduction. This year’s cutback is the fourth since 1997, when the annual limit was 67,300.
Thomas also reports on some research conducted by former fisheries biologist Lance Beckman that suggests the estimates of sturgeon predation by sea lions might be just “the tip of the iceberg”:
“Beckman has spent almost 14 hours making observations between late November 2009 and mid-December 2010. He’s counted sea lions kill 10 sublegal sturgeon, 22 legals, 47 oversize and 17 he could not classify. That’s 96 fish.
“Important is the fact that 96 sturgeon were observed killed during the 13.7 hours I was there,” he said. “It is very significant that seven sturgeon were killed per hour of observation. If you expand the number killed per hour observed to total daylight hours and a given number of days, you can estimate that many thousands of sturgeon are killed even with these limited observations.”
But here’s the kicker: From the U.S. Army Corps of Engineers viewing site, only 14 or 15 of those kills would have been observable. Data collected by Corps observers the past few years has been used to show how sea lion predation is increasing.”
In December, Oregon and Washington biologists estimated sea lions could eat up to 10,600 sturgeon in the lower Columbia River this year, including 800 spawners.