New research aims to help this Louisiana fish and the environment it lives in

In Louisiana estuaries, scientists are scrambling to collect information on spotted and alligator gar non-lethally — a game-changer for the scientific community — to see how floodplains and native habitats are faring.

These results led to a new study published in Transactions of the American Fisheries Society.

Spotted Gar collected during fieldwork in the Upper Barataria Estuary, Louisiana.

The spotted gar and the alligator, freshwater fish found in the Mississippi River watershed and other parts of North America, have typically been used for habitat condition research. through isotopic analysis, in which scientists examine the muscle tissue or stomach contents of fish. .

But this method kills the fish, said Thea Fredrickson, lead author of the new study. She now works as an aquatic biologist in Austin, Texas, but began this work in 2018 as part of her thesis while a graduate student at Nicholls State University in Thibodaux.

“It just got me thinking about whether there are ways to do it that it’s not a deadly method, like using fin tissue instead of muscle tissue,” Fredrickson said. . “I like to think I’m part of a solution.”

Nicholls State University is home to the GarLabled by fish ecologist and assistant professor Solomon David and students whose research focuses on the ecology of migratory and ancient fish.

David, another study author, said the new method involves taking small samples by cutting the fins. Gar can quickly regrow their fin tissue, he added, and they also tag animals to track them over time.

In Louisiana, gar is a common fish, even considered a “trash fish” by some people due to a lower perceived value than more common game fish like bass or trout. But Fredrickson hopes to change those preconceptions through their work.

“I like the idea that we’re changing that perception and trying to get people to care about them,” Fredrickson said.

Although globally marked as a species of least concern, local extinction exists among fish in the northern part of their range, such as Ohio, Illinois, and the Great Lakes region. By conducting this study in more abundant populations, the scientists hope that this non-lethal tool will allow sampling of more vulnerable populations outside of Louisiana.


Kent Ozment and Solomon David


The GarLab team, left to right, Audrey Baetz, Dinah Cador, Solomon David, Derek Sallmann, and USFWS Fisheries Biologist Kayla Kimmel release a tagged Alligator Gar.

“The fact that we can do this without killing the fish is a big win,” David said. “Any time you can collect scientific data without having to sacrifice the animal, especially sensitive populations with very large and very old individuals, that’s beneficial.”

Through fin clipping, David said, scientists find out how the diet of guys changes throughout the year and how different fish populations vary based on location.

Watching the alligator gar is like a blast down memory lane. The gar family has been around for about 159 million years, with species that can live for several decades. They serve as good markers showing how their habitats are doing.

With spotted gar, these fish are good indicators of the health of ecosystems and populations. Gar can also help translate genetic information from more commonly used fish for applications in biomedical research.

Scientists are also working with the Nature Conservancy and the Louisiana Department of Wildlife and Fisheries using information collected from gar fish as a way to see how different floodplain restoration efforts are going.

Floodplain restoration is important in Louisiana because it creates spaces to filter and store water, can help with resilience against storms and land loss, and supports biodiverse ecosystems.

“We want to use the guys as an indicator of how restored floodplain habitats are being used and how these important ecosystems might change over time,” David said.

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