ODNR study hatchery trout
By Jane Beathard
Are the waters of Ohio’s most popular trout-fishing streams growing too warm for the fish to live?
Biologists hope to answer that question by studying the growth, movement and survivability of brown trout developed at the London State Fish Hatchery, according to Joe Conroy of the Ohio Department of Natural Resources (ODNR). Conroy is heading the four-year study for the ODNR’s wildlife division.
This week, Conroy and other division staff are injecting 25,000 brown trout yearlings with electronic tags prior to stocking the fish in Clear Creek, Clear Fork Creek and the Mad River. Those three fast-moving streams are meccas for trout anglers.
A nearly-invisible “wire tag” injected into the snout of each fish will differentiate brown trout stocked in 2012 from those stocked in 2011 — the first year of the study. Second tags, placed in strategic locations in trout bodies, will allow Conroy and other biologists track fish as they grow and swim in the three waterways.
Data gathered will be compared to readings from temperature monitors in each stream to see if hot summer weather affects trout movement or even kills off the cold-loving fish.
Results could eventually influence state fishing regulations or stocking procedures. Scientists might also find ways to protect hatchery-raised trout, Conroy said.
“Since the last two summers were the hottest on record, we need four years of data to make good decisions,” Conroy said.
On Wednesday, ODNR staff worked feverishly to tag 5,000 young trout headed for Clear Fork Creek in north central Ohio. Another 5,000 tagged fish will go that way on Thursday. Clear Creek in southeastern Ohio will get 3,500. Western Ohio’s Mad River will get 11,500. About 500 fish are stocked in each mile of river, Conroy noted.
Next August, biologists will collect brown trout from each stream, comparing their locations and size to long-term water temperatures in the area. They want to determine the relationship between the number of July days that water temperatures are above 75 degrees and the size and number of fish that survive the heat.
Conroy noted the tiny wire tags are virtually undetectable by anglers who hook a research trout. However, the data those tags deliver is important.
“It’s a very popular fishery,” he said. “Trout anglers have been very understanding.”
It’s fees paid by boaters and anglers that fund the current study.
“The whole program is dependent on Sport Fish Restoration money,” Conroy said.
The federal Sport Fish Restoration Act (SFRA) of 1950 returns revenues from manufacturers’ excise taxes on sport fishing equipment, import duties on fishing tackle, yachts and pleasure craft and a portion of the fuel tax on small boat motors to the states, based on a formula.
SFRA is one of several wildlife-related programs currently under scrutiny during the federal budgeting process.