No, she isn't listening to her iPod. Biologist Taylor Phillips is actually working, listening for beeps that emanate from specially tagged New River walleyes. The headphones are connected to a hydrophone, a powerful underwater microphone, that picks up the beeps when Phillips' boat passes within 100 meters of a tagged fish.
SANDSTONE - Deep beneath the surface of West Virginia's New River, a transmitter implanted into a fish's belly lets out a telltale beep."I've got a fishy!" said biologist Taylor Phillips.Phillips has spent all spring and most of the summer listening for beeps. They tell her how far each of the transmitter-equipped walleyes has traveled from where she first captured it."The idea is to track the seasonal movements of New River strain walleyes," said Phillips, a fisheries technician for the state Division of Natural Resources. "We know Sandstone Falls is an important spawning area for them, but we don't yet know where they go after they spawn."The picture still isn't complete, but it's starting to come into focus.In late February, Phillips implanted sound-emitting "acoustic tags" into 20 walleyes, all captured from the river just downstream from the falls. After the spawning season ended, the fish began drifting downstream, most of them for miles and miles."A few of the fish made it as far downstream as Hawks Nest Lake, which is as far as they could go because Hawks Nest Dam acts as a barrier," Phillips said. "That surprised me. I expected them to migrate downstream; I didn't expect them to get all the way to Hawks Nest, but they did."Most of the tagged walleyes strung themselves out like pearls along the 44 miles of river between Sandstone Falls and Hawks Nest. Phillips expects them to eventually migrate back upstream to spawn, but she isn't sure when the migration might begin.
"Right now, the fish seem to be hanging around in the areas they migrated to," she said.To find the tagged fish, Phillips drifts downriver and dangles an omnidirectional hydrophone - a highly sensitive underwater microphone - off the boat's gunwale. Wearing headphones, she listens intently for beeps from the walleyes' tags."If I hear a beep, it usually means I'm within about 100 meters of one of my tagged fish," she explained. "When I get a strong beep, I switch to a directional hydrophone that allows me to pinpoint where the fish is."Phillips logs each fish's tag number and GPS coordinates on a notebook. When a fish moves, she knows about it.
In addition to the live tracking she does three or four days a week, she also collects data from a network of six "passive" acoustic receivers submerged at strategic points along the river. When a fish passes near one of the receivers, a mini-computer inside the receiver detects the beep from its tag and logs the fish's tag number, the date and the time. To collect the data, Phillips snags the receivers' anchor cables with a grappling hook, hauls the units to the surface and downloads their accumulated information onto a laptop computer.Problems crop up from time to time. Not long ago, a fisherman caught and kept one of the tagged fish. Three of the original nine passive receivers have malfunctioned. Curiosity seekers have found receivers' anchor cables and hauled the units up onto the riverbank. Still, Phillips believes she's getting plenty of usable data.DNR officials hope her study will help them restore the New River's once-vibrant walleye fishery.
The river once was renowned for its oversized walleyes, but a combination of environmental factors set the fishery into decline. The DNR tried to rebuild it by stocking Great Lakes-strain walleyes, but the stocked fish never seemed to thrive.In 1999, researchers at Virginia Tech discovered that the New River had two distinct strains of walleyes - a native strain that had been there for millennia, and the stocked strain from the Great Lakes.Armed with that knowledge, fisheries officials in Virginia and West Virginia switched their emphasis to the propagation and stocking of New River-strain fish. Since 2003, nearly 69,000 young natives have been stocked in the New between Bluestone Dam and Hawks Nest.Producing thousands of juvenile walleyes each year isn't easy. DNR crews must first capture mature fish as they're preparing to spawn, identify whether the captured fish are of the native strain, strip eggs from the females and milt from the males, fertilize the collected eggs, allow them to hatch, and stock the resulting fry back into the river.So far, capturing brood stock has been a major bugaboo. The New River in late February - the walleyes' prime spawning period - can be a hostile place. If the river is running high, its swift currents prevent biologists from collecting walleyes as they queue up to spawn.Phillips' research might ultimately help biologists to more effectively gather brood fish.
"If we know when the fish are going to show up [at the spawning grounds], we can time our collection efforts accordingly," she said. "We'll be able to collect fish closer to the time when they would actually spawn, which will put less stress on them. Also, there's a chance we'll identify other spawning areas."After Phillips completes her study next spring, she'll incorporate the information into her master's thesis for Ohio University. She'll also share her findings with other biologists."I intend to share the information with fishermen, too," she added. "When they see me on the river, they ask me where I'm finding the fish. Maybe my research will help them find fish, too.Reach John McCoy at 304-348-1231, or firstname.lastname@example.org.