Radio tags, telemetry used in river-bass-movement research

By Jeff Mulhollem
July 09, 2014

UNIVERSITY PARK, Pa. -- If you catch a smallmouth bass in the Susquehanna or its tributaries, with a wire trailing from its underside, it is a participant in a study of fish movement related to wider research into the causes of fish diseases in the river system.

Release the fish unharmed and don't tamper with or cut the wire, urges Penn State researcher Megan Kepler. She pointed out that it's an antenna from a radio transmitter that allows the fish to be tracked with telemetry technology. The "Lotek radio-sensor tags" not only allow identification of the fish, but also log the water temperatures that the fish is living in.

A doctoral candidate in the University's Intercollege Graduate Degree Program in Ecology, Kepler surgically implanted 40 of the $300 devices in smallmouth bass this spring and plans to insert them in 45 more later this year. They will allow her to track the movement patterns and habitat use of the fish.

"Since the early 2000s, smallmouth bass throughout the Susquehanna River and many of its tributaries have exhibited characteristics of disease, including lesions, black spots and deformities," she said. "Management agencies have been trying to determine why this is happening by assessing the bass population, conducting fish-health surveys, studying parasites, and measuring many water-quality variables -- such as temperature, dissolved-oxygen levels, pH, and contaminants."

To supplement this work, the Pennsylvania Cooperative Fish and Wildlife Research Unit in Penn State's College of Agricultural Sciences is conducting a fish-movement study in the West Branch of the Susquehanna River and two of its major tributaries, Pine Creek and Bald Eagle Creek.

The tags are expected to emit a signal for about a year, Kepler noted, which will allow researchers to follow bass in the research project throughout critical periods, including spring (pre-spawn and post-spawn), summer (when river bass respond to low, warm flows), and late fall (when fish move to overwintering habitat).

A primary goal of the research is to identify if and when fish are moving in and out of the tributaries, and to determine how this movement might relate to various environmental conditions, such as water temperature, as well as in relation to key fish-life events, such as spawning.

"Understanding movement and life-history characteristics of smallmouth bass has implications for both disease and fish management," Kepler said. "For instance, little is known about the range of bass movement in this system and if fish are moving into and out of different tributaries seasonally. Overall movement of bass will allow us to better understand the disease stressors that bass may be subjected to."

"It is also important to understand what types of habitat -- in this case mostly thermal selection -- fish are using seasonally to highlight areas for protection and to better characterize habitat selection throughout various temperature regimes," she said. "As a scientist and also an avid outdoorswoman, I am interested in trying to better understand this system, and in the end, help to manage and protect the resource in the best way possible."

Kepler is asking for assistance from fishermen on the Susquehanna and its tributaries:

--Return any caught fish with a radio-tag back to the water and do not modify the antenna in any way. "The external antenna allows me to identify where the fish is and which fish I am locating," she said.

--Report bass caught. "I have received a few contacts already and it is helpful for me to know these fish are behaving normally and feeding," she said. "I'd like to know a general location where the fish was caught and released and the condition of the fish."

Collaborating on the research are the U.S. Geological Survey, the Pennsylvania Fish and Boat Commission, Susquehanna University, Pennsylvania Sea Grant, and the state Department of Environmental Protection.

Megan Kepler can be contacted at

  • radio tagged bass

    A smallmouth bass from the West Branch of the Susquehanna River, with a radio tag implanted. Note the wire protruding from it's underside.

    IMAGE: Penn State

(Media Contacts)

Last Updated July 10, 2014