Tis the season for experimentation at fish hatchery
Once, execution of the plan was as simple as the plan itself.
Want fish for stocking? Hatch some eggs, throw the “fry” — or tiny, half-inch or shorter fish — in a tank, add food occasionally and wait to see what survives.
Things are different these days.
The Pennsylvania Fish and Boat Commission remains in the business of stocking fish — and not just trout — in waters around the commonwealth. But how those fish are produced is changing, Necessity in the form of tighter budgets is prompting innovation.
Take muskies at the commission's Linesville fish hatchery, for example.
In years past, the commission spawned muskies in spring, cultured those eggs and stocked fish — 80,000 annually — that same fall. They averaged about 7 inches in length.
Starting in 2018, it's going to stock half as many fish, but all will be bigger. When they're turned loose in June, they should be 12 to 14 inches, said Jared Sayers, hatchery manager at Linesville.
Better survival is behind the switch.
Jason Detar, a biologist with the commission, said monitoring of stocked muskies — some are tagged — shows four times as many of the larger ones were alive after a year compared to the smaller ones.
“It takes a pretty big bass to eat a 14-inch musky,” he told commissioners earlier this year.
That should lead to more fish and better fishing long-term, Detar said.
Getting larger muskies is no simple feat, though. It means keeping them in the hatchery an extra eight months or so.
That's where the experimentation comes in. At Linesville — part fish farm, part science lab — it's all about tinkering.
“I'm a spreadsheet geek,” Sayers said. “I've got data on growth rates compared to feed ratios, growth rates compared to the density of fish in a raceway, you name it. I've got more data than I can make sense of right now. But there are answers in there. It's our job to figure it out.”
They've seen some success already.
Traditionally, raising muskies until they're a foot or longer has meant starting them on dry feed and then switching to live minnows.
But minnows are expensive.
At Linesville, Sayers said, they've learned to get muskies to go from pellets to minnows and back to pellets.
That's keeping costs down while still producing quality fish, he said.
“The addition of the minnows, even for a period of time, changes their behavior,” Sayers said. “It makes the muskies more tame to our presence here in the hatchery. But it makes them much more aggressive eaters, even of the dry feed. And that helps them continue growing.”
At Linesville, fish culturists also are experimenting with channel catfish.
Historically, the commission has stocked channel cats as fingerlings, meaning when they are just a few inches long. Sayers and his crews are holding some up to age 2, however, to see how large they can grow them.
The payoff could be big, he believes.
The commission this year hosted two channel catfish programs aimed at families, one in North Park, the other in Philadelphia. It purchased channel cats to stock for the North Park one.
The plan is to do two more events in 2018, this time buying fish for both.
Sayers hopes to be able to supply those fish in-house eventually. He already has some pushing 10 to 12 inches and hopes he might have some near 20 in time.
“That would be a really nice fish for someone to catch,” he said. “And that's what we're about: trying to create excitement.”
Of course, lots of other fish pass through Linesville in a year's time.
It's home to brown trout destined for co-op nurseries and ultimately Lake Erie right now. Steelhead will make a brief appearance soon.
Later, the hatchery will get down to its real bread and butter. That's walleyes. Crews will catch 7,000 or so adults and collect more than 90 million eggs. The result will be about 65 million fish.
They'll be in and out of the hatchery quickly.
“Once those walleyes hatch, they have to be gone in three days,” Sayers said. “If you hold them until Day 6, you'll have a string of walleyes the length of the raceway. There will be a walleye with the tail of another in its mouth, with that walleye having another by the tail, and that one having another by the tail, until they're one big string of fish trying to eat one another.
“It's the craziest thing you've ever seen.”
After that, crews spawn muskies and then largemouth bass, all while raising panfish and minnows, collecting channel catfish eggs and more.
Things are going to get busy soon, Sayers said. That's why now, over winter, is when experimentation is king.
“We're always looking for better ways to do things,” he said.