OLYMPIA — The downward trend in the number of legal-size sturgeon in the lower Columbia River has stopped and the population has started to increase.
“It’s creeping back up,” Cindy LeFleur, regional fish program manager, told the Washington Fish and Wildlife Commission on Saturday. “It’s going in the right direction.”
The long-used mark-and-recapture method of estimating the population between Bonneville Dam and the ocean shows 83,400 sturgeon ranging from 38 to 54 inches fork length in 2012.
The method has a lag time to allow tagged fish to be recovered before determining a population estimate.
o The number of Steller sea lions just downstream of Bonneville Dam increased steadily through 2011, peaking at 89 animals. That dropped to 73 in 2012 with 80 observed in 2013.
o Observed consumption of sturgeon at Bonneville during 2013 decreased 75 percent from the 2012 level.
o The harvest guideline of sturgeon was exceeded slightly in 2013. Sportsmen went 115 sturgeon over their guideline of 7,797, while commercial fishermen were 55 under their guideline of 2,021.
o Data from 2012, the most recent year available, show harvest of sturgeon in the Washington coastal estuaries and Puget Sound sport fisheries totaled 328 fish, 4.2 percent of the lower Columbia sport total for that year. Sport harvest in Oregon rivers and estuaries has averaged 2.5 percent of the lower Columbia amount during the past 10 years.
o Catch rates of sub-legal sturgeon in the sport fishery has been stable for the past five years and the rate for legal-size fish has increased in the past three years.
o The 2012 traditional-method estimate of 83,400 could be as few as 54,700 or as large as 137,000 given statistical confidence intervals.
o The number of Steller sea lions just downstream of Bonneville Dam increased steadily through 2011, peaking at 89 animals. That dropped to 73 in 2012 with 80 observed in 2013.
o Observed consumption of sturgeon at Bonneville during 2013 decreased 75 percent from the 2012 level.
o The harvest guideline of sturgeon was exceeded slightly in 2013. Sportsmen went 115 sturgeon over their guideline of 7,797, while commercial fishermen were 55 under their guideline of 2,021.
o Data from 2012, the most recent year available, show harvest of sturgeon in the Washington coastal estuaries and Puget Sound sport fisheries totaled 328 fish, 4.2 percent of the lower Columbia sport total for that year. Sport harvest in Oregon rivers and estuaries has averaged 2.5 percent of the lower Columbia amount during the past 10 years.
o Catch rates of sub-legal sturgeon in the sport fishery has been stable for the past five years and the rate for legal-size fish has increased in the past three years.
o The 2012 traditional-method estimate of 83,400 could be as few as 54,700 or as large as 137,000 given statistical confidence intervals.
The 83,400 is up from 72,800 in 2011 and 65,300 in 2010.
A newer method involving setlines projects the 2014 legal-size population at 131,700, up from 114,200 in 2013 and 72,700 in 2012.
“We did expect this growth,” LeFleur said. “It’s smaller fish moving up into the legal size.”
Sturgeon retention will stay closed in 2014 downstream of Bonneville Dam, plus in coastal estuaries and Puget Sound. Washington and Oregon wanted to start non-retention in 2013 to help the population, but delayed one year at the request of guides who already had booked trips.
LeFleur showed the commission a graph profiling the sturgeon population by year-class. That graph predicts the legal-size population will decline again in a few years.
“We might expect a drop off in recruitment to legal size in a few years,” said Brad James, Washington’s sturgeon manager.
Robert Fehlen of Washougal, representing the Coastal Conservation Association-Washington, said his group supports no sturgeon retention in sport or commercial fisheries in 2014.
The decision “reflects concern for the health of the sturgeon population as a whole, the depressed state of the legal-size population, and the need to allow time to replenish the number of legal-size fish,” Fehlen said. “Brood-size fish must be given more opportunity to survive their term in the legal-size population.”
Harry Barber of Washougal, also with CCA-Washington, said there were 29 days of gillnetting between Woodland and Beacon Rock in 2013. That could be as many as 10,000 drifts with the nets , he added.
The netting was at night with no limit on soak times and no boxes to recover lethargic fish, he said.
Soak time limits and recovery boxes are not required in fall.
“Considering both the magnitude of the oversize (sturgeon) bycatch in gillnets, and the intensity of the fishery, it is most likely that many of these oversize fish suffer multiple encounters with gillnets,” Barber said. “They might even have multiple encounters on the same night.”
He questioned if low young of-the-year numbers and poor spawning success are linked to female sturgeon absorbing their eggs instead of spawning.
Barber also said the confidence intervals in the new setline method of estimating the sturgeon population are plus-or-minus 70 percent.
“I’d use extreme caution using the setline data,” he said.
Barber said the drop in predation by Steller sea lions on sturgeon immediately downstream of Bonneville Dam may not necessarily be a good thing.
“It might be because the fish are not there,” he said. “I think we’re driving them out of the Gorge.”
The Washington commission plans a public hearing on its lower Columbia sturgeon policy in January. The proposed policy does not include a population size at which retention in fisheries would reopen.
LeFleur said those details would be worked out in an accord with Oregon if the commissions approve retention fisheries.
Adoption of the Washington lower Columbia sturgeon policy is anticipated in February.
