Fish and Boat Commission biologist Freeman Johns holds a 30-inch, 12.8-pound walleye pulled from the Allegheny River.
Are walleye populations in the Allegheny River capable of sustaining themselves?
That’s a question Pennsylvania Fish and Boat Commission biologists are trying to answer. A final determination is still several years away.
But, a first hint is closer at hand. Beginning this winter, the agency will be examining ear stones from walleyes pulled from the river to determine if they were fish born and raised there naturally, or introduced via stocking.
The last walleyes stocked in the river, in 2008, were dipped in a bath of oxytetracycline before being released. That process stained their ear stones, also known as otoliths.
Biologists collected adult walleyes from the river this fall. The ear stones were removed, with the idea of examining them under a microscope.
If they’re from stocked walleyes, they’ll glow under ultraviolet light. If they’re not, they won’t.
Biologists will compare the number of glowing versus non-glowing stones so as to be able to say whether stocking or natural reproduction is playing a bigger role in supporting the fishery, said Tim Wilson, a biologist in the commission’s area 1 office in Linesville. That will direct future management decisions.
The hope is that natural reproduction is to credit for most of what’s swimming out there, he added.
“That’s the big question. Is it enough?” Wilson said.
If it is, the commission can use the limited number of walleyes it can raise in hatcheries to support other fisheries, he said.
“Obviously we’d prefer those fish take care of themselves. That saves us money and allows us to make better use of our hatchery fish elsewhere. That’s the goal,” Wilson said.
Results of this winter’s work will be available likely no sooner than spring, Wilson said. The work will then be repeated over at least three more winters.
Only when all of that information is collected will the commission debate any possible changes to the river’s walleye management plan, he added.