LJ Trout movement study

afishinado

afishinado

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If this weekend, there's an antenna sticking out of the trouts arse on the LJ....let it go!

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


Link to source: http://www.centredaily.com/sports/outdoors/article150406452.html
 
Thanks for the link and story.

Many of us have followed this study with great interest. Hopefully the new methods will continue to reveal more about the much misunderstood issue of wild trout movement in large watersheds.
 
Far out, man!
 
Glad to see my alma mater doing good things.
 
Thanks for sharing that info, very interesting stuff. It surprises me though, that the larger trout moved more often than the smaller ones. I would have thought the bigger fish would be more territorial and stay put more often.
 
wildtrout2 wrote:
I would have thought the bigger fish would be more territorial and stay put more often.

What happens after they eat all the small fish in their home pool?

Moving around to take advantage of prey available in other locations makes sense. FWIW, I've heard from second hand sources that similar studies on western rivers also showed that many bigger fish have large home ranges and can cover a large amount of territory when conditions are favorable for feeding. However, they also showed that while the fish will travel great distances with, they also tend to return to a rather small home area with regularity.
 
I am going to be at my 35th Juniata College Reunion in two weeks and will let everyone I meet involved in this study know that Paflyfish.com appreciates what they are all doing.
 
PennKev wrote:
wildtrout2 wrote:
I would have thought the bigger fish would be more territorial and stay put more often.

What happens after they eat all the small fish in their home pool?
Most of my bigger wild browns were caught in pools/holes that appeared to be devoid of other trout. It's not like bigger trout only feed on small fish/trout.
 
wildtrout2 wrote:
PennKev wrote:
wildtrout2 wrote:
I would have thought the bigger fish would be more territorial and stay put more often.

What happens after they eat all the small fish in their home pool?
Most of my bigger wild browns were caught in pools/holes that appeared to be devoid of other trout. It's not like bigger trout only feed on small fish/trout.

That doesn't really disprove the idea of fish moving long distances to hunt then returning to a safe/comfortable home. Also, It doesn't surprise me that a particularly? large fish would eat or run off any smaller fish. The fact that they also eat small prey or bugs doesn't prove that they aren't also trying to find a big meal.

I suspect the size of the waterway being studied will likely influence results. Larger streams like the LJR or a big western river are much more conducive to fish movement and foraging behavior. A smaller stream with limited cover and holding water will probably result in a different conclusions about fish behavior. As far as how much fish move, I think the fish in the LJR will move more than most trout in smaller streams, and I think you would find that fish in the upper Allegheny would move even more than the LJR fish, and that is only taking into consideration the size of the waterway. Forage, structure, flows, water temp, etc are all likely going to affect how trout act.
 
This is an excellent study and the results will be quite valuable. Thanks for posting the update.
 
wildtrout2 wrote:
Thanks for sharing that info, very interesting stuff. It surprises me though, that the larger trout moved more often than the smaller ones. I would have thought the bigger fish would be more territorial and stay put more often.

Yes, I found this the most interesting! It's also encouraging if "Walter" isn't home anymore in his favorite haunt. He may not have been kept or killed or died; he may have just moved on...
 
Nymph-wristed wrote:
wildtrout2 wrote:
Thanks for sharing that info, very interesting stuff. It surprises me though, that the larger trout moved more often than the smaller ones. I would have thought the bigger fish would be more territorial and stay put more often.

Yes, I found this the most interesting! It's also encouraging if "Walter" isn't home anymore in his favorite haunt. He may not have been kept or killed or died; he may have just moved on...

I think you will find that the size of a stream factors into trout movement too. On a small stream, Walter is going to stick around in the best habitat he can find. There may not be enough water in the stream for him to move. In a bigger system like the little J, there are not as many constraints or maybe reasons for a big fish to stay put.
 
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