ASHLAND — Every time Chilli Swopes catches a Howard Prairie rainbow trout with a missing left ventral fin on its underbelly, he wonders two things: How did that fin disappear, and does it make the lopsided fish swim in circles?
"We keep catching these fish and wondering why is this fin missing?" says Swopes, of Eagle Point.
The clipped fin means it's a Cranebow, a descendant of bad-ass trout from Crane Prairie Reservoir that can grow to more than 10 pounds in its native reservoir.
Cranebows are now getting a test-drive to see how they fare in this other prairie infested with illegally stocked smallmouth bass.
And, no, they don't swim in circles.
Without knowing it, Swopes and other Howard Prairie anglers this summer are in the midst of a great experiment to figure out future trout-stocking regimens here. And keeping a close eye on the fins will tell them which strain of rainbows are filling their coolers.
Last fall, the Oregon Department of Fish and Wildlife stocked Howard Prairie with three strains of sterile rainbows, each strain with different fin-clips, which allows biologists to more easily gauge how well they survive, thrive and contribute to the five-trout daily limit at one of Jackson County's most popular angling lakes.
Included in the batch were 107,964 of the traditional Roaring River rainbows, a standard grade of trout first bred at the Roaring River Hatchery in Scio. They were stocked at about 6 inches in length and have a clipped adipose fin, which is along the back between the dorsal fin and the tail.
Another 15,640 similar-sized rainbows were of the Troutlodge strain out of Washington. They have no clipped fins.
The Cranebow fingerling, which were 4 to 5 inches long, numbered 36,339, and it was the first time the strain was ever stocked in Jackson County waters. They sport the clipped adipose and left ventral fins.
While signs detailing the various fin clips are posted at the marina, most anglers are blind to the experiment.
"To be honest, I've never paid attention to it," says Bob Jackson, a 69-year-old Fremont, California, man who spends about three months camping and fishing at Howard Prairie each summer.
He's not alone.
"There are notices around, but nobody notices the notices," says Bingo Bill Powell, who works at the resort marina.
ODFW has done some creel surveys at the lake, and so far they are showing that the Troutlodge trout are faring best, says Dan VanDyke, ODFW's Rogue District fish biologist.
Despite their larger numbers, the Roaring River trout are not contributing to the fishery as they should be, VanDyke says. The agency plans to de-emphasize and possibly eliminate Roaring River trout from the lake's fall stocking regimen, he says.
For all their hype, the Cranebows have been a virtual no-show in creel surveys, data show. One possible reason is because they were stocked at a smaller size than the others, likely leading to heavier predation by smallmouth bass — the scourge of Howard Prairie and the reason for the stocking experiment.
"The Cranebows got eaten," VanDyke says. "That's what I think happened."
ODFW has been experimenting with fall fingerling stocking ever since illegally introduced smallmouth bass began exerting their unwanted presence on Howard Prairie's trout population a decade ago.
"The last eight or nine years, the bass have decimated everything," Jackson says. "It's sad, but it's still beautiful up here."
The premise behind the fall stocking — or inclusion of larger-than-average fingerling — is that the larger fish have a better shot at dodging bass, particularly in the fall when cooler water slows down the warm-water-loving bass.
VanDyke says he plans this fall to stock as many as possible of the Oak Springs strain of rainbows in the lake. Oak Springs join Roaring River as the mainstays of Oregon trout-stocking, and some planted in the fall of 2009 did well here.
Trout lovers have been rooting for the Cranebows to do well, and despite their poor showing so far, VanDyke plans to work them into the stocking equation again in 2018 and 2019, when grant money for the fin-clipping experiment runs out.
"Regardless, we seem to be maintaining a pretty good fishery in the face of illegal fish stocking," VanDyke says. "We're just trying to make it better."