More details are coming out about last week’s large-scale joint state-tribal survey on Lake Roosevelt, one that alarmingly turned up a 6-pound pike just 10 miles from Grand Coulee Dam and a 27.5-pound northern in the upper Spokane Arm, but may have also reduced bycatch over last fall’s effort.
Fishery managers say that it’s all about figuring out the best way to suppress pike populations to keep them from chewing up the reservoir’s more popular game fish species.
Asked about angler concerns over nontarget species also being netted, WDFW’s Chuck Lee defends, “If it doesn’t get done, those (hatchery trout) aren’t going to be around either.”
A 31-inch, 10-pound pike caught in one of the agency’s 50 net sets had a 16-inch rainbow in its stomach.
The other primary worry with pike is that the invasive nonnative species will get into the anadromous zone below Chief Joseph, the next dam below Grand Coulee, with its ESA-listed salmon and steelhead stocks.
“Adult sockeye aren’t too much bigger than that rainbow trout,” Lee points out.
Roosevelt also hosts white sturgeon, kokanee, burbot, lake whitefish — one that was 2 pounds heavier than the state record was sampled last week — walleye, smallmouth bass and yellow perch.
This is the second fall survey in a row and WDFW took the upper portion of Roosevelt while the Spokane Tribe worked the Spokane Arm and midsection with 50 net sets and the Colville Tribes hit from the dam to Hawk Creek with yet another 50.
If there’s good news, it’s that the Colvilles caught only that one pike in their 37-mile lower reservoir stretch.
“As alarming as it was, we’re glad it was only one fish,” Lee says.
But more and more are turning up midlake, he adds.
Overall, 152 were caught, with 112 by WDFW in their area of responsibility.
Lee notes that for this survey adjustments were made in where the agency set its nets.
“We figured we could eliminate 40 percent of the bycatch by moving them shallower,” he says.
Some deeper sets last year also came up empty.
Figures were still being crunched but Lee says less than 20 fish were caught per state soak.
The comanagers’ overall goal is to figure out how they can get the best bang for their buck with the effort.
“What we’re really trying to find out is, What’s the best way to monitor northern pike and measure suppression efforts — which is the best season for doing suppression?” Lee says.
While spring and the spawn is a good time, the weather is often poor and the reservoir is drawn down. But fall’s stable conditions may be more ideal.
Either season is good if you’re a species that managers and anglers want to save, thanks to cold to cooling water temperatures that make it more likely released fish will survive.
Lake whitefish and nets, however, aren’t a good combination, which most being killed.
A spring 2017 survey saw survival rates of 45 percent for walleye, 37 percent for hatchery rainbows, and greater than 50 percent overall for other species.
“We want to learn from suppression efforts to do it better,” Lee says, adding that funding is a bit of a problem.
Money has been coming from the Northwest Power and Conservation Council.
As for other results from this fall’s survey, that ginormous 27.5-pound pike caught by the Spokane Tribe was a relatively rare specimen as tribal suppression efforts — both netting and $10 rewards for fish heads — appear to be resulting in younger and younger pike, the number one goal, according to Lee.
Smaller pike have fewer eggs, but the species is one you can’t let your guard down on either.
Befitting their reputation as “nightmare fish,” Lee says northerns can hold off spawning till later in the year, when water temps are otherwise well above their optimal range of 40 to 52 degrees Fahrenheit.
“All they need is a little vegetation,” Lee says.
Correction, 11:15 a.m., Nov. 14, 2018: The initial version of this blog stated that WDFW had caught 152 pike in this fall’s survey, but that was actually the overall catch by the state and tribes. WDFW’s nets caught 112 pike.