This is from the WDFW Weekender Report. Hope this helps.
North Central Washington:
Fishing: Anglers who stuck it out through the rain and cold of the April Fools' Day fishing season opener in the Columbia Basin caught lots of big, fat rainbow trout, reports WDFW district fish biologist Jeff Korth of Moses Lake. "But that weather literally put a damper on the length of the average fishing trip and overall catch per angler averages that we measured April 1," he said. "That was especially true at the waters on the Columbia National Wildlife Refuge, like the Hamptons and the Pillar-Widgeon chain. There were a lot of anglers out at those lakes, but they didn't stay long."
Korth says boat anglers, including those in float tubes, trolling hardware or flies tended to do much better than the boat or shore anglers using bait. Anglers at Upper Hampton Lake averaged almost three over-15-inch yearling rainbow trout each. Those at Lower Hampton averaged two 15-inchers each. Widgeon Lake anglers averaged a little less than three 10-inch-plus yearling rainbows each, with some 15-inchers checked. Those at Pillar averaged 1-1/2 near-14-inch rainbows each. Few fish were checked at the other eight lakes in the Pillar-Widgeon chain, but those that were averaged about 13 inches.
Opening day weather was better up at Dry Falls Lake, Korth says, but fewer anglers were checked there; those that were averaged a little over two fish each, mostly 14-inch rainbows with a few 18-inch rainbow and brown trout. "I expect catch rates to be much better in these lakes with more favorable weather conditions," Korth said.
Meanwhile, WDFW fish hatchery crews are busy this month stocking waters that open April 29 with more catchable-size trout, including sterile triploid rainbows. The triploids average one-and-a-half pounds when they go into the lakes, and since they don't reproduce, they quickly eat their way to trophy size if not harvested in the first year. Wapato Lake in Chelan County and Conconully Lake and Reservoir in Okanogan County are among the waters receiving triploids in the next weeks. Stay tuned to the next edition of the Weekender Report for more information on the northcentral region's fishing hot spots for the biggest season opener of the year.