There might soon be an answer to the age-old question of whether anglers should fish for muskellunge during the summer.
Researchers in West Virginia and Virginia are studying whether muskies caught in warm water die after being released. Jeff Hansbarger, the West Virginia Division of Natural Resources’ resident muskie expert, said the project makes sense because of the states’ location.
“We exist on the southern end of the muskie’s natural range,” Hansbarger explained. “Muskies are cool-water fish that prefer water in the 55- to 70-degree range. The waters of West Virginia and Virginia often get considerably warmer than that.”
Warm water doesn’t hold as much dissolved oxygen as cool or cold water. Hansbarger said warm water, coupled with muskies’ tendency to fight hard when hooked, triggers physiological changes that can cause the fish to die later.
“Eighty degrees is sometimes described as a benchmark,” he added. “But that has never been studied, at least in waters this far south. We’re hoping to answer the question of, ‘How warm is too warm?’”
To do that, they’re radio-tagging and releasing muskies early in the year when the weather is cold, and are relying on summertime anglers to report when they catch them.
The study focuses on fish caught in lakes, rivers and ponds. The river component of the survey is taking place on Virginia’s James River, the lake component at West Virginia’s Stonewall Jackson Lake, and the pond component at West Virginia’s Palestine Fish Hatchery.
Peter Jenkins, a graduate student at West Virginia University, is handling the field research at Stonewall Jackson.
“We have 45 radio-tagged muskies, and I’ve been tracking them since the water temperatures reached 80 degrees,” Jenkins said. “The fish we captured in the coves and bays during the spring have since moved into the main stem of the lake, where the water is deeper and cooler.”
Stonewall’s deepest reaches have water that is plenty cold enough for muskies, but that water doesn’t hold much oxygen because it lies below the lake’s thermocline, a layer that separates the warmer surface waters from the cold depths below.
Jenkins said Stonewall’s thermocline lies about 15 feet below the surface, and the lake’s muskies tend to cruise just above it.
“The water temperature just above the thermocline is 65 to 70 degrees, which is a nice temperature for the species,” he continued. “But when people catch a muskie from Stonewall during the summer, they pull it up through water that is much, much warmer.”
So far, Jenkins said, 15 muskies have been recaptured by anglers.
“Only six of the recaptures have occurred since water temperatures started exceeding 80 degrees,” he continued. “Of those six fish, one died.
“That fish was caught during the second week of July. The fish engulfed the bait, and one of its gills was bleeding when it was landed. The angler tried to revive the fish for quite a while, but couldn’t. Because of the gill injury, the fish’s mortality couldn’t be placed exclusively on water temperature.”
Of the 15 fish caught so far, Jenkins said five or six were caught by anglers who were trolling, three or four by anglers who were jigging, five by anglers who were casting, and one by a bass fisherman who just happened to catch it.
Jenkins said he’s “pushing anglers hard to get to locations where muskies are congregated so we can try to get more recaptures.” Since Stonewall is well-known for a muskie “trolling bite” that occurs in August, he probably won’t have to push all that hard.
Muskies aren’t usually found in small ponds, but a portion of the mortality study is being conducted in 1½-acre ponds at the Palestine Hatchery in Wirt County.
DNR biologist Hansbarger said that aspect of the research was the brainchild of WVU professor Kyle Hartman, who designed it so biologists could have control over oxygen levels and the entire group of muskies being studied.
“Half of the fish will be angled for, and half won’t,” Hansbarger explained. “At the end of the year, we’ll drain the pond and we’ll either find the fish alive or dead. We’ll know exactly how much mortality occurred. And because we have aerators in the ponds, we’ll have some control over the amount of dissolved oxygen in the water.”
Another WVU graduate student, Taylor Booth, is doing the field work at Palestine, monitoring 13 muskies separated roughly half-each into a pair of ponds.
“All the fish are tagged [with electronic transponders] so they can be identified,” he said. “I’m going to try to catch about half of them.
“I’ll record the mortality from the ones I catch, and from the ones I don’t catch. If there are significant differences, we should be able to determine that high temperatures are able to affect them.”
Booth has caught three of the fish so far, one of which died after being released. Overall, he said, the muskies’ survival in the shallow ponds has been good despite water temperatures that have topped 90 degrees.
“They’re doing OK, but they aren’t biting,” he added. “They’re just swimming around in there. I’ll probably wait until after the first of September before I start fishing for them again. The water should be back down in the 80-85 degree range by then. That’s the range we’re most interested in.”
Next year, Booth plans to expand the study and have 20 to 25 muskies in each of the two ponds.
“The information we gather will provide some numbers for that age-old debate,” he said. “All the research so far has been anecdotal.
“There have been mortality studies done, but the temperatures in those studies never reached more than 75 degrees. This will be the first data from a hot-water environment.”
Hansbarger said the findings might eventually affect how West Virginia manages its muskies.
“In South Carolina, anglers aren’t allowed to fish for striped bass in lakes when water temperatures are high because there’s so much more mortality,” he said.
“I would rather not have to [impose] regulations unless we absolutely have to. This study should give us a better answer on whether regulations are or are not justified.”