After weeks of refusing to crank over given the relatively large forecast, the spring Chinook count at Bonneville fired up the past two days with a combined 10,310 fish, giving hope that this year’s upper Columbia run is just woefully tardy due to a mix of environmental conditions. Stable flows out of the dam could yield more good daily counts after a period of depressed figures that will have given fishery managers heartburn.
While the return still has a long way to go to hit the preseason prediction of 198,600 at the mouth of the big river, Monday and Tuesday bring the year’s tally to 38,652 springers at Bonneville.
Those figures were also posted after what’s known as the U.S. v. Oregon Technical Advisory Committee met at the start of the week to go over the count, river flows and water temperatures. After viewing the data, TAC didn’t issue a runsize update but did put out the following statement.
“The adult passage at Bonneville Dam to-date is less than would be expected given the pre-season forecast and recent-year average run timing. TAC currently expects both the total run and the natural-origin run are likely to come in less than the pre-season forecast. At this point in time, the total run could be less than the buffered pre-season forecast even if passage is as late as observed in 2017.”
The “buffered pre-season forecast” refers to the 30 percent taken off the top of the above-Bonneville run as a safety against overprediction and which the early fishery on the Lower Columbia is managed around. This year’s wrapped up April 11 with just 26 percent of the available mortalities taken, 1,715 of 6,487 adult springers, leaving plenty of fish still available.
TAC is scheduled to meet again next Monday, May 15, and a runsize update, even if to confirm the lower buffered forecast, could help shake loose some more time on the water.
For Ryan Lothrop, WDFW’s Columbia River fisheries manager, what appears to be a late surge of springers is another 2023 curveball that goes along with this year’s late smelt arrival, perhaps due to colder than average water, and then a huge bump in flows out of Bonneville. Volume jumped from 150,000 cubic feet per second on April 26 at Cascade Island to just over 350,000 cfs by last weekend.
“The dramatic increase in river flows during typical peak passage time likely had an effect on counts. It would be nice to see elevated counts this week continue as flows temporarily stabilize prior to more water coming downstream,” Lothrop said, a reference to unusually hot mid-May weather expected late this week and early next.