Surveys show stocking bigger channel cats produces better fisheries
This is an experiment that seems to be working.
For decades, the Pennsylvania Fish and Boat Commission has stocked channel catfish in various waters around the state. The fish were always released as fingerlings, about 2 to 3 inches long.
Biologists knew some would get eaten by other fish – primarily largemouth bass – but the hope was enough would survive to adulthood to create fishing opportunities.
Results were iffy at best.
Here's an example.
Upper and Lower Twin lakes in Westmoreland County, near Greensburg, had been stocked with fingerling channel catfish for some time. So, in 2009 and 2010, respectively, biologists in the commission's area 8 office in Somerset County surveyed them to see how what that effort was producing.
The answer was not much.
They discovered just two channel cats in Upper Twin, and only one in Lower Twin, said Mike Depew, a commission biologist.
That prompted a change.
The commission has continued stocking channel cats in each lake. But since 2014, half were the usual fingerlings, while the other half were yearlings, or fish averaging 9 to 10 inches long.
All were fin clipped, the smaller fish in one unique way, the larger ones in another.
The idea was to see which turned up more frequently in subsequent surveys. Meaning, is it more productive in the long run to stock lots of small fish or fewer but larger ones?
So far, it seems bigger is better.
Biologists surveyed three lakes in southwestern Pennsylvania – Upper and Lower Twin and Canonsburg — earlier this year. They checked the fin clips to see whether the fish handled were released as fingerlings or yearlings.
All three have some natural reproduction occurring. But stocked fish accounted for most of the fish collected.
And yearlings dominated.
Take Lower Twin, for example.
"We handled 39 channel catfish, with 31 of those having yearling clips and one having a fingerling clip," Depew said.
The story was the same at Upper Twin. There, biologists got 120 channel cats. Fin clips showed 87 had been stocked as yearlings, Depew said. They found none that had been stocked as fingerlings.
More than a few of the fish from each lake were impressive, too.
"Some of our yearlings from 2014 had grown to 26 and 27 inches in both the Upper and Lower lake, which is much faster growth than I have seen anywhere in western Pennsylvania," Depew said.
Canonsburg Lake in Washington County revealed similar results.
"At Canonsburg we captured 102 channel cats, with 67 of those having a yearling clip and one having a fingerling clip," Depew added.
So bigger does seem to better, at least when it comes to producing a channel cat fishery.
Whether that will lead to stocking all yearlings in all waters remains to be seen. About 30 waters across the state – from North Park Lake in Allegheny County to Lake Nessmuk in Tioga to Shawnee Lake in Bedford and Lake Galena and Lake Luxembourg in Bucks – get channel cats, traditionally as fingerlings.
But the commission is examining closing some hatcheries, and all stockings are a bit up in the air.
What's not in question is whether bigger is better.
"That's what the literature suggested would happen, and so far that's proving to be true," said area 8 fisheries manager Rick Lorson.
Looking beyond channel cats
So what else is swimming in Upper and Lower Twin lakes and Canonsburg Lake?
At Upper Twin, biologists collected lots of largemouth bass, with some big ones in the mix. Crews handled184 fish ranging in size from 5 to 17 inches.
That worked out to a catch rate of 283 fish per hour, with 70 fish per hour longer than 12 inches and six per hour longer than 15.
A quality "big bass" lake, according to commission standards, produces 35 fish per hour, with seven longer than 12 inches and two over 15.
Things were even more impressive at Lower Twin.
There, biologists got almost 300 bass ranging in size from 4 to 22 inches. The catch rate was 332 fish per hour, with 132 longer than 12 inches and 16 longer than 15.
Biologist Mike Depew said crews also got "decent numbers" of crappies — 49 black and 81 white — at Lower Twin. They ranged from 3 to 14 inches.
"Numbers of fish in the 8- to 10-inch range weren't high, but there seemed to be unusually high numbers of fish from 11 to 14 inches. We'd pull a few real nice ones out of every net it seemed," Depew said.
Bluegill numbers were good with 166 fish landed. All went between 2 and 8 inches, with 36 percent exceeding 7.
At Canonsburg, Depew said crews got "abundant numbers" of crappie and bluegills. But most were small, with only a handful of crappies over 9 inches.
"The bass population was good, although numbers declined from the previous survey," he added.
Crews handed 58 bass from 6 to 19 inches. That was a catch rate of 64 per hour, with 25 over 12 inches and 9 over 15.