Statistics are a guideline, not a gospel. So, the following spring chinook salmon catch statistics from the lower Columbia River for April are informative, but not the last word on where to catch fish.
Washington and Oregon combined spend about $1 million each year between February and October sampling sport fishermen. The river between Tongue Point near Astoria and Bonneville Dam is divided into 10 sections for sampling purposes.
Twice a week, once on a weekday and once on a weekend, the Oregon Department of Fish and Wildlife makes a flight from Bonneville to Astoria counting boats and bank rods.
To come is the catch data for the 21 days in April sport fishing was open. These numbers are not about total fish caught.
The numbers are “catch-per-unit-effort,’’ a commonly used measure of angling success. If two anglers go fishing, and they get one fish, the CPUE is .5. If eight go fishing, and they catch one, the CPUE is .125.
Water conditions in the lower Columbia play a big role in CPUE. Dirty water reduces success. Low streamflows hurt the bank fishery, while high flows help it.
With all those caveats, here were the top five locations in April and their CPUE: 1. the Oregon shore at Bonneville Dam, .683; 2. boats in the Cathlamet-Westport area, .406; 3. boats in the Columbia Gorge between Reed Island at Washougal and Beacon Rock, .398; 4. the Washington shore at North Bonneville, .382, and 5. boats in the estuary (downstream of Puget Island to Tongue Point, .378.
The second five include: 6. the Oregon shore in the Deer Island-Sandy Island area, .366; 7. boats between the Longview Bridge and the downstream end of Wallace Island, .271; 8. boats in the Kalama-Sandy Island-Deer Island area, .257; 9. boats in the Woodland-St, Helens area, .254, and 10. the Oregon bank in the St. Helens-Marker 72 area, .249.
If the CPUE of .683 off the Oregon shore at Bonneville seems unreal, well, it was the result of very unusual circumstances.
The catch all came in the final week of the season and the vast majority of it was inside the mouth of Tanner Creek.
"The sea lions were chasing fish off the mouth of the creek, but it was too shallow for the sea lions to get in the creek,'' said Jimmy Watts, an Oregon Department of Fish and Wildlife biologist. "However, every time a sea lion would swim by the mouth of the creek, the bite would turn on.
"There was only enough room for about 15 anglers to fish at one time, but were about 20 to 25 others waiting. As one angler would limit, another would rotate in to take his place. The anglers told the checker the sea lion was 'helping them,' which has got to be a first.''
A couple of other notes:
• Other than at North Bonneville, the catches off the Washington beaches were poor in April.
• The worst CPUE for boaters came in the metro area. Camas-Washougal was poorest at .153, followed by Kelley Point to Warrior Rock at .190 and Davis Bar to the Portland airport tower at .196.
• This next number is unrelated to spring chinook catch this year, but perhaps relevant in 2013. Through Tuesday, there were 8,254 jack spring chinook counted at Bonneville Dam. The 10-year average for the date is 21,853.
Allen Thomas covers hunting, fishing, hiking, skiing and other outdoor recreation topics for The Columbian. He can be reached at email@example.com and 360-735-4555. He can be followed on Twitter at @col_outdoors.