New study shows key behavioral, physical impacts of increasing water temps on sculpin, headwaters7/2/2024 ![]() Susquehanna University graduate Danielle Tryon, center, recently completed a study on how sculpin react to thermal changes in streams. At left is a sculpin at Stony Run, near Lewisburg. Top right is the network of manmade stream channels Tryon used to study the sculpin at Susquehanna's Freshwater Research Institute and bottom right is a sculpin being measured in the lab. Riverkeeper note: The following story and podcast package was created/written by Middle Susquehanna Riverkeeper John Zaktansky. You can contact him directly here. Much more active than originally anticipated, freshwater sculpin instinctively swim upstream when threatened by thermal changes in headwater environments even when cooler water options are not accessible according to a study by recent Susquehanna University graduate Danielle Tryon. “We expected to see changes over time in their physical condition, but what we didn’t realize was that this species moves around as much as it does when stressed by water temperature changes,” said Tryon, who conducted the study over the course of a year using manmade stream channels at the university’s Freshwater Research Institute (FRI). “These channels are recirculating, and each is the same temperature throughout, but in channels with higher temperatures, the sculpin instinctively swam upstream to search for cooler water, which is fascinating,” said Matt Wilson, head of the FRI. “It would be easier to say they found cold water randomly and just sat there, but in these channels where temperatures were consistent across the moving water, they automatically swam upstream to look for relief. There wasn’t any randomness about it.”
Waterway impacts
In both scenarios, regardless of whether a sculpin was impacted physically or behaviorally, there can be an immediate effect on the aquatic ecosystem, according to Tryon. “Sculpin are just a specific part of a bigger food web, where trout are near the top of the aquatic food web. If sculpin react to thermal stress by moving out of a certain section of waterway, you are going to see an increase in macroinvertebrates and algae,” said Tryon. “It is like removing an important part of a puzzle, and then just telling the remaining species to figure it out on their own and hope for the best.” Wilson agreed. “Sculpin are middle predators – they eat macros and fish eggs while also functioning as food for trout. If you think about a stream with both sculpin and trout in it, you get this interaction where sculpin are at the bottom eating bugs and other things which allow the trout to feed more on the surface,” he said. “If sculpin aren’t there, it changes things for all the species remaining. This all requires more research to know more about what would happen specifically, but there is a definite change.” What’s next In fact, Tryon admits there are numerous potential next-step studies with sculpin that could help us better understand the aquatic ecosystem and how to better protect it. “We could go in and add discharge at high flow rates that could be caused by different phenomenon or a low discharge to represent drought situations. As we change those discharge circumstances, we can pair it with thermal fluctuations and learn so much more,” she said. “We can also go in and add blocks in the channels to look at culvert or dam impacts to the species in relation to thermal changes, or put sediment in the water to look at turbidity and how mucking up the water influences species.” Tryon’s efforts to make these stream channels at the Freshwater Research Institute viable for research opens many potential doors for future research, Wilson admitted. “I have a couple of ideas around stream morphology and how particles move in a stream and to look at deposition and erosion. It would be cool to also experimentally measure how sediments build behind structures like beaver dams,” he said. “I am also interested in doing some bigger food web experiments. Like introducing various salamanders, species of fish and aquatic insects, but doing a much longer experiment.” Tryon, who has moved to Alaska since her Susquehanna University graduation, where she works on research involving salmon weirs, admits that her time at Susquehanna and this study specifically has helped her realize a lifelong dream. “Growing up, I always wanted to be a scientist. Being at Susquehanna and working in the labs and the Freshwater Research Institute, and then various opportunities with the (Middle Susquehanna) Riverkeeper association have provided so many great opportunities to be the scientist I always wanted to be,” she said. “I learned to be adaptable to be in the field doing studies, to see things in a different way and hopefully have been able to help in at least a small part with my work.” Along those lines, everyone – scientist or not – has the ability to make a difference, Tryon added. “Be curious and don’t be afraid to ask questions,” she said. “Find people in your community, whether it is through a nonprofit or a university or even a neighbor, and ask your questions, learn more about this world and your place in it and then get involved.” Those interested in getting involved in various ways with the Middle Susquehanna Riverkeeper Association are encouraged to fill out the group's online Susquehanna Survey.
2 Comments
Rob Barbour
7/2/2024 05:56:58 pm
Not being a biologist or hydrologist I have wonder for years now the impacts the gas industry industrial water withdrawals are having on our watershed feeder streams. When millions of gallons of freshwater are sucked out of streams daily such as the Loyalsock Creek that means the feeder streams must empty quicker to fill that void. Less water means higher water temps. for what water is left. With at least 3 current water withdrawal sites and now possible a 4th (EQT's in Hillsgrove) The Loyalsock Creek is potentially loosing 6-8 million gallons a day, day after day. I would bet my next retirement check that the SRBC has not taken any such research as you have done into consideration when they rubber stamp industry water taking projects. I think you are scratching the surface of the impacts of water temperature on our aquatic life in our streams. Keep up the solid scientific work. Rob Barbour
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John Zaktansky
7/5/2024 08:32:43 am
Rob,
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AuthorsRiverkeeper John Zaktansky is an award-winning journalist and avid promoter of the outdoors who loves camping, kayaking, fishing and hunting with the family. Archives
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