Two groups to partner for second trout movement study

A transmitter is surgically implanted by Dr. Uma Ramakrishnan in a wild brown trout. This year's transmitters will be half this size and less likely to be expelled.
A transmitter is surgically implanted by Dr. Uma Ramakrishnan in a wild brown trout. This year's transmitters will be half this size and less likely to be expelled. For the CDT

Juniata College and the Little Juniata River Association are set to embark on their second wild trout movement study on the Little Juniata River. Forty trout will be fitted with transmitters to allow researchers to follow their movement through this summer and fall. Depending on river conditions, the start date will be late May or early June.

Both groups learned a lot from their 2015-16 study — and, this time, they want to do it better. According to the researchers, several problems plagued the first study. With hindsight and additional supportive research, they hope to circumvent those issues this time around.

“We just were not ready for the mass movement that occurred with trout beginning in mid-August,” said Dennis Johnson, professor of environmental science and information technology at Juniata College in Huntingdon.”We plan to conduct daily monitoring this summer and hopefully track the trout as they start to move.”

The Little Juniata has 36 miles of main river that flows through Blair and Huntingdon counties, and another 540 miles of tributary streams. That makes for a lot of places for trout to navigate — and for a lot of potential problems to arise.

Tyrone was one of the three sites used last year, but Johnson said that electrical interference there posed a problem for him and the students attempting to monitor movement.

“This time, we are using only two sites — one on the upper river at Bellwood and Barree on the lower river,” Johnson said. “It is the upper river that gets the highest summer water temperatures.”

Another issue stemmed from a few transmitters that just showed up in the river or on the stream bank sans fish. At the time, Johnson suspected predators or anglers. A follow-up experiment conducted in conjunction with the Pennsylvania Fish and Boat Commission at their Benner Spring Research Station demonstrated that some trout could actually expel the transmitters right through the sides of their bodies. A second Benner Spring study showed that trout would be less likely to expel a smaller, lighter-weight transmitter.

“We will use slightly larger trout and smaller transmitters this year,” Johnson said. “The transmitters weigh just a little more than half as much as the transmitters used in 2015 — only 2.6 grams, compared to the larger 4.3-gram transmitters used in the first study.

“Each transmitter gives off a unique frequency. The only drawbacks are that the smaller units have a shorter battery life and are less powerful. Transmission intervals will be adjusted to ensure that the batteries will last through the fall spawning season.”

Juniata College biologist Uma Ramakrishnan and her team will surgically implant the small transmitters in 40 wild brown trout that are a minimum of 14 inches long. In 2015, there were zero mortalities as a result of the surgeries, and Ramakrishnan hopes for the same success this spring.

“It takes 3-5 minutes for the anesthesia to work, then 2-4 minutes for the surgery and then about 10 minutes for the trout to begin to recover,” Ramakrishnan said. “After that, we observe each trout for about two hours before releasing it back into the river.”

Little Juniata River Association president Bill Anderson was disappointed that the first study did not answer their original question — where do trout go when water temperatures reach lethal levels?

“We had a cool summer in 2015, and that was good for the trout, but it didn’t provide the type of thermal stress that happens most summers,” Anderson stated. “We want to learn how the trout on the upper river survive when the water temperatures reach near 80 degrees.

“In the 2015 study, we learned that the trout use much more of the river than we thought,” Anderson stated. “Big trout move more than smaller trout, and most trout movement is associated with high water events. We also saw that trout moved in response to turbidity (mud in the water).”

This second study, like the first, is truly a collaborative project. According to Anderson, the Little Juniata River Association purchased the 40 transmitters for $7,000, and its members will help to capture trout. Juniata College will handle the surgeries to implant the transmitters and monitoring of the trout as they move in the river. A new partner this year will be the Pennsylvania Fish and Boat Commission.

“The last time anglers caught all of the trout for the study, but the catching was spread out over three months,” Anderson said. “This time, Commission southcentral regional biologist Kris Kuhn will be electro-shocking the river so that we can get all 40 study trout in a shorter amount of time. Anglers will help, too, which gives them a sense of ownership in the study.”

Considering the transmitter expense and the time invested, the researchers ask that any angler catching a trout trailing a silver antenna to please return it to the river. With favorable river conditions, tagged trout will be transmitting their locations to the researchers by June 1.

Mark Nale, who lives in the Bald Eagle Valley, is a member of the Pennsylvania Outdoor Writers Association and can be reached at MarkAngler@aol.com