When a stocked rainbow trout comes across a big wad of dough bait floating off the lake bottom, it harkens back to a time when life was so easy and being a fish was so simple — those two years of swimming in circles along with 10,000 of its closest friends in a hatchery rearing pond, waiting for the guy with the blue bucket to come by and toss in food pellets.
Sure, the fish-meal pellets were ground-up Uncle Charlie, but they were so easy to find and tasted so good. And it remembers the aroma of those pellets. It was so alluring, just like the enormous gob of light green dough bait now floating so invitingly in front of its eyes.
It's a hatchery rainbow's comfort food — virtually irresistible.
"Hatchery-reared trout are suckers, so to speak, for big ol' pieces of food sticking out in front of them," Keith Jones says. "It just really appeals to them. It's somewhat similar to what they've seen before."
And nothing says big-ol' piece of food more than PowerBait, that doughy piece of heaven brought to you by Jones and his fellow researchers at Berkley whose piscatorial version of crack cocaine is a rage that hatchery trout across North America cannot resist.
Dough baits are the most popular way to catch Oregon's most populous trout — stocked rainbow — and Berkley's version remains the go-to offering for trout-o-philes who will trek to their favorite haunts April 23 for the traditional start of trout season.
And that's not by luck.
Jones and other Berkley researchers in Spirit Lake, Iowa, concocted PowerBait in the 1980s specifically to prey on a hatchery trout's psyche — one shaped and honed from its time finning around concrete ponds and eating fish meal that is imitated, albeit exaggerated, by these dough baits.
Jones, who studies fish behavior, calls it "supermodeling."
Anglers call it heaven-sent, though the science behind it is far more clinical and methodical than your typical weekend worm-drowner may ever expect.
It preys upon what fish learn in hatcheries, lessons not so easily forgotten.
"It's sort of like a Pavlov response, but within trout," says Rhine Messmer, recreational fisheries program manager for the Oregon Department of Fish and Wildlife. "They're domesticated. A cultured animal. And they definitely develop patterns in the hatchery. And floating bait imitates what they were used to eating in the hatchery setting."
Thinking like a fish is something Jones has done for decades, much of it centered around the highly exploitable notion of what fish crave.
In the wild, tiny trout first eat zooplankton. When that doesn't cut it anymore, they switch to small insects and work their way up to small fish. Really large trout end up becoming cannibals, because that's the best way to get nourishment for its effort, Jones says.
Hatcheries are different.
They school in unnaturally large groups, their surroundings are virtually devoid of predators, and they are conditioned to eat fish-meal pellets.
"Walk up to the pond and, if you have a bucket in your hand, they'll come right to you," Messmer says.
Once released, they will continue to school, swimming in circles while trying to figure out what's food and what's not.
"They're not dumb, per se, but they are ignorant," Jones says. "They don't know what to do. They're not prepared for what they're up against.
"When you're raised in a hatchery, things are pretty limited for you," he says. "There's not a whole lot of experience there."
Fly-fishers targeting native trout will match the hatch. For stocked trout, it's match the batch.
Berkley hired Jones in 1985, and he worked the first 21/2 years on what became the prototype for PowerBait, which was first tested in March 1988 at June Lake in California's Sierra Nevada mountains.
It's based on the concept of supermodeling, taking what an animal knows and exaggerating some factors "to make it look like something it's eaten before, but more appealing," Jones says.
The big dough balls are not fish meal, but they have the taste and smell of it, triggering that learned response that this is food.
"They just happen to be larger, and larger is now more attractive to them than those smaller pellets."
The first colors were pink and yellow, but Berkley now sells about 100 versions of PowerBait in 200 color variations. Company officials decline to discuss overall sales.
Chartreuse remains one of the most popular colors, but it's not necessarily the best, Jones says.
Berkley doesn't test to see which color works best, Jones says. But as Berkley's vice president of development consumables, Jones continues to do scent tests on PowerBait.
To do so, they use a single color so bait color won't skew their results. That color is a lemony chartreuse chosen because it was easy to make, Jones says.
"I've sat on a dock with a number of other anglers and my catch rates with that color are substantially higher then theirs," Jones says.
But that's one color Berkley doesn't sell.
"I keep telling them, 'Guys. Use this color out there,' " Jones says. "Just shows you what kind of pull I have around here."
Reach reporter Mark Freeman at 541-776-4470, or email firstname.lastname@example.org.