ASHLAND — A new experiment to see whether the best rainbow trout of Central Oregon can improve Southern Oregon's angling experience has biologists wondering whether the bounty for one prairie can improve things at another.
The Oregon Department of Fish and Wildlife has embarked on a new study to see whether a new breed of trout stocked in the fall at Howard Prairie can better survive bass predation, grow larger and perform better at the end of anglers' fish hooks.
The contestants, all marked with different fin clips, are the old standby trout called Roaring River, a new come-along Troutlodge strain from a private Oregon hatchery, and the beasts of Crane Prairie Reservoir — the mighty "Cranebow."
Cranebows, which were originally bred from wild rainbows from Crane Prairie tributaries, have the reputation for packing on poundage into the teens, and the 36,339 released last month as sterilized five-inchers into Howard Prairie marks the first time Cranebows have been released in the Rogue Basin.
"If we see one of them really producing and showing up more, that will be intriguing and something we'd want to look at," says Dan VanDyke, ODFWs Rogue District fish biologist.
"The Roaring River is one of our two standards that have been in the hatchery system for decades," he says. "We're looking to see if another one's better."
The relatively shallow, weedy and insect-loaded Crane Prairie is not like the deeper, rockier Howard Prairie, so Cranebows might not beat out the rainbow standard Roaring Rivers, VanDyke says. Then again, Cranebows have not been inbred for as many generations as its rivals.
But, hey, they're all sterile. So there's no harm in trying.
"We really need to do this here and see how it works for this fishery and our anglers," VanDyke says.
To test this, biologists are doing a two-prong approach of a standard mark and recapture study.
ODFW fish biologist Dave Haight set and pulled three gillnets in Howard Prairie this week and counted the relative recapture abundance of each candidate.
Of the 159,943 fish stocked there in October, Tuesday's gillnet catch showed no difference in the early survival of Roaring River and Troutlodge stocks, which were all about seven inches long, and both survived at rates VanDyke sees as very successful.
However, the Cranebows had a lesser survival rate, possibly because their smaller size made them easier prey for illegally stocked smallmouth bass — the very reason why ODFW is looking for new strategies here after stocking 250,000 fingerling each spring for several decades.
The real test will come where it counts the most.
VanDyke says he plans an aggressive creel survey there next year to see the sizes and abundances of all three strains of trout at Howard Prairie.
Anglers can do the same thanks to the clipped fins funded by a $4,500 grant from the state Restoration and Enhancement Program funded by a surcharge on fishing licenses.
The Roaring River trout have the traditional clipped adipose fin on the small of their backs. The Troutlodge fish are not clipped, while the Cranebows have both their adipose and left ventricle fins clipped.
The left ventricle, known as LV in the fish-research world, is the left rear fin and, no, clipping it won't make them swim sideways.
Creel survey crews will hit the now year-round Howard Prairie hard during the traditional Opening Day period of late April and continue into May, VanDyke says. Spot-checks will then proceed monthly, he says.
Fish will be measured and the fin clips checked to denote the strain of the caught trout. The numbers of fish counted in each strain will be compared to the numbers of fish released in the fall. Their sizes will also be compared to each other.
"We want to talk to anglers throughout 2017 to see what they're catching," VanDyke says. "We definitely want to get observations of those fish."
This year's batch of Cranebows were tossed into this study only because Willamette Hatchery had some excess and VanDyke hopped on them.
He expects to do some similar hopping next year to keep rolling this noble experiment of whether one prairie can successfully outfit another.
"We'll find out more next year," VanDyke says.