You won’t find mad scientists roaming Pennsylvania lake shores. Not unless they’re just out fishing, anyway.
But there are two experiments going on in a handful of waters.
Both have the same goal: to figure out whether there are better, more economical ways to provide good channel catfish angling.
The first experiment involves spawning. Channel cats are cavity nesters, meaning they prefer to lay their eggs in things like rock piles, hollow logs, holes in the bank and the like, said Rick Lorson, the Pennsylvania Fish and Boat Commission’s Area 8 fisheries manager in Somerset, who’s heading up both research projects.
Those are in surprisingly short supply in a number of waters statewide, though. Tim Wilson, a biologist in the commission’s Area 1 office in Linesville, said that in decades past, whenever manmade lakes were created, most of what is recognized as habitat was removed to protect the dam structures. The result often was lakes with bottoms as smooth as bowls.
It really affected fish populations from top to bottom, Wilson said.
The commission artificially sustains some fisheries in such situations via stocking. The commission raises 150,000 to 200,000 channel catfish annually in its Linesville, Union City and Pleasant Mount hatcheries, said Rob Brown, northern hatcheries production manager for the agency. They’re released into waters chosen by biologists.
It could spread those fingerlings around to more, different waters if some of the places getting them now had self-sustaining populations, Lorson said.
That’s where the first experiment comes in.
Commission biologists surveyed five lakes Oneida in Butler County, Bessemer in Lawrence, Beltzville in Carbon, Sweet Arrow in Schuylkill and Kyle in Clearfield last year and this one to assess their catfish populations.
The lakes range in size from 28 to 946 acres. All traditionally are stocked with catfish. They aren’t getting any through 2020, though.
Instead, crews with the commission’s habitat management division will sink spawning boxes 32-by-18-by-13-inch rough cut hemlock structures, with a 6-inch circular entrance hole at one end in each at a rate of three per acre. They’ll monitor them for use between 2016 and 2020.
Biologists then will return to the lakes and resample them in 2019 and ’20 to see whether the gap in stocking has been filled by wild fish spawned in those boxes.
We want to find out if we can have an impact on channel catfish at the population level, Lorson said.
It’s clear spawning boxes work, said Ben Page, lake habitat section chief for the commission. Hatcheries have used similar devices to spawn catfish fingerlings for decades. Looking at nest boxes in lakes using underwater cameras and snorkelers with dive lights likewise has shown that, in more than 50 percent of cases, catfish not only use them but also defend them, he said.
The channel cats we’ve encountered are very aggressive. They’ll bite your light.They’ll bite the camera. They’ll bite your hand, Page said.
But whether enough catfish are nesting successfully, whether enough of their young are surviving to adulthood to support an acceptable fishery, and whether the size of a lake plays a role in any of that are all less clear, Lorson said. He’s hoping the experiment will answer those questions.
Our ultimate objective is to maintain pretreatment levels of abundance and be able to discontinue stocking and still provide a quality fishery, he added.
The second experiment underway involves stocked channel cats.
Traditionally, the catfish stocked by the commission are 2 to 4 inches long when released, Brown said.
That may be too small. Lorson said scientific literature suggests if catfish are stocked at lengths shorter than 8 inches, most get eaten by predators such as largemouth bass.
So through 2018, four lakes Canonsburg in Washington County and Upper and Lower Twin and Lower Burrell Park Pond in Westmoreland are being stocked with two sizes of catfish. Some are the traditional 2-inch specimens, and others will average closer to 9 inches. All will be fin-clipped the smaller fish one way, the bigger ones another before being released.
Biologists will resurvey the lakes in 2017 and ’18 and examine all of the catfish they find to see what percentage originated from each size group.
Basically, all we’ll need to do is count the clips and determine which size survives better. If we see the bigger fish are surviving better, we’ll make a bid to stock all of our lakes 100 acres or less with the bigger fish, Lorson said.
We’re going to try to demonstrate that if you do have bigger fish going in, you’re going to have more fish coming out.
Commission hatcheries raise no channel cats as large as 9 inches, Brown said. Even for the purposes of supporting this study, they’re buying them from elsewhere, he added.
But if the study shows producing bigger fish which means keeping them in the hatchery longer, at greater expense leads to better survival in the long run, it may change our approach, Brown said.
Lorson hopes all of the work between the two studies leads to better fishing.
Indications are catfish are surging in popularity among anglers, he said. They provide action starting in mid-summer, when other fishing such as that for trout is slowing down, he added.
Those things, he believes, make them worthy of some attention.
We are seriously interested in them here in this office, Lorson said.
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