Legal-size sturgeon in the lower Columbia River appear to be at their lowest number since the early 1990s and sport-fishing success its poorest in 20 years.
Upstream in Idaho, fish managers are enacting new tackle restrictions in January to help reduce the lethal impact anglers have on the increasingly popular catch-and-release fishery for trophy sturgeon in the Snake and Salmon rivers.
Research presented last week by Washington and Oregon fisheries agencies estimates the lower Columbia population of 42- to 60-inch sturgeon below Bonneville Dam was 87,000 in 2009. That’s down 14 percent from 101,200 in 2008.
Biologist Brad James of the Washington Department of Fish and Wildlife said the decline is in the 42- to 48-inch portion of the population. The 48- to 60-inch portion is stable. The catch rate of 15 legal sturgeon per 100 angler trips is the poorest since 1991.
The 2010 Steller sea lion count at Bonneville Dam was the highest since observations began in 2002. California and Steller sea lions combined to kill almost 2,000 sturgeon during 3,600 hours of observation this year at Bonneville.
That’s up from about 1,700 in 2009 and 400 in 2006.
Idaho’s sturgeon numbers have stayed fairly stable since monitoring began in the 1970s, said Joe DuPont, state fisheries manager in Lewiston.
But research has indicated that a Hells Canyon sturgeon requires 40 years to reach spawning sizes of 4-5 feet long and at least 70 years to reach the 7-foot-and-larger sizes anglers love to catch and release.
“Just one percentage point increase in the mortality rate can have a tremendous impact on fish that take that long to mature,” he said.
New rules starting in January may improve angler success while reducing unnecessary impacts to sturgeon, he said.
One rule will require a sliding sinker on a leader that’s lighter than the main line.
When anglers break off, the sinker will remain in the water while the hook can be retrieved.
“A young sturgeon will die if it ingests a hook attached to a broken off sinker stuck on the river bottom,” he said.