University of Idaho graduate Curtis Roth studied how long a fish can be held out of water for his master’s thesis from 2016 to 2017 — and he recently published his final findings.
Roth studied under the advisement of Associate Professor Michael Quist. Roth was able to release three studies about how air exposure affects different types of trout. The most recent, “Effects of Air Exposure During Simulated Catch-and-Release Angling on Survival and Fitness of Yellowstone Cutthroat Trout” was published in the North American Journal of Fisheries Management on Dec. 14, 2018.
“The work was sponsored in part by Idaho Department of Fish and Game,” Quist said. “It was tied to Recreational Fisheries and Catch-and-Release Harvest regulations. Curtis has since graduated and he’s now a biologist for Idaho Department of Fish and Game.”
Quist aided Roth by advising him on how to design the study, conduct field work, analyze his data and write the final studies. Roth also received assistance from Daniel Schill, Brett High, Matthew Campbell and Ninh Vu from the Idaho Department of Fish and Game. Everything else — from start to finish — was Roth’s own work for his master’s thesis.
“This was all part of my graduate research, so I was a master’s student at the time,” Roth said. “I was responsible for all the field work, all the data analysis. Granted, I had a lot of help along the way from my advisor and the other co-authors.”
Roth found that anglers — people who fish with a rod and hook — hold fish out of water for approximately 20 seconds and rarely longer than 60 seconds. After this discovery, Roth studied the effect of holding fish out of water for different periods of time up to 60 seconds. In each case, Roth found that there was no effect on the fish.
“The take-home message on (the portion of the study that focused on reproduction) was that there was no effect on reproductive potential,” Quist said. “So, regardless of how long fish were held out of water for up to a minute, the reproduction was similar across the groups.”
To test that his hypothesis further, Roth studied the effect of air exposure in different water temperatures, on different species and in the young of the trout he originally studied. Even with these differences, Roth still observed no harm to the fish from air exposure.
Roth felt inspired to pursue this research because most studies to date on the effect of air exposure on fish use lab data. Quist said this leads to inaccurate results because the conditions do not match what happens in the field.
“There has been a group of scientists who have done a lot of work on this and honestly, there are a lot of issues with that work,” Quist said. “For example, they’re doing work on fish in a laboratory, they’re not using wild fish, they’re using hatchery fish, animals are confined, things which are really problematic from a scientific standpoint. The other thing is they’re holding fish out of water for really long periods of time — two minutes, four minutes, there’s one study that’s nine minutes, one that’s eight minutes, some that are 16 minutes holding fish out of water, one that’s 90 (minutes), so really long periods of time.”
Roth and Quist hope their research brings comfort to anglers in Idaho. Quist says Roth’s work is the most comprehensive set of studies to date on the effect of air exposure on fish.
Both Quist and Roth encourage anglers to use good, safe practices while fishing, but that they shouldn’t fear taking a picture with their catches.
“(This research) supports the idea that they have the ability to enjoy these fish, take them out of the water to admire them, take a picture with them, those kinds of things,” Roth said. “We just don’t want to limit the public’s opportunity to do something like taking pictures of the fish when there’s not really a biological reason to do so.”