Knee-deep in the San Antonio River and strapped into a large, beeping backpack, Austin Davis looks like a ghostbuster in search of water ghouls.
With a yellow electrical rod, he sweeps through the water in front of him, sending a current into the river. He swings the rod back and forth as he moves toward two teammates holding a wide net downstream.
When he stops, the other two lift the net to reveal about 50 fish flopping in the middle, slightly shocked from the electricity that momentarily paralyzed them and pushed them downstream.
After a second’s pause, the team lets out a cheer.
“We got a Texas logperch,” Davis calls out.
Aquatic biologists Steve Bittner, left, Zoe Nichols, middle, and Austin Davis walk to the San Antonio River along Mission Reach to trap fish as part of the San Antonio River Authority’s Nekton Survey on Tuesday, Nov. 23, 2021. The survey monitors fish diversity.
Billy Calzada /Staff photographer
Aquatic biologist Steve Bittner shows a red shiner that was trapped in a net as part of the Nekton Survey for the San Antonio River Authority on Tuesday, Nov. 23, 2021. The survey monitors fish diversity.
Billy Calzada / Staff photographer
Aquatic biologist Austin Davis examines a Guadalupe bass that was trapped as part of the Nekton Survey for the San Antonio River Authority on Tuesday, Nov. 23, 2021. The fish was measured, and a bit of fin taken for DNA sampling before it was released. The survey monitors fish diversity.
Billy Calzada /Staff photographer
Aquatic biologists Zoe Nichols, left, Austin Davis, middle, and Steve Bittner prepare to trap fish as part of the San Antonio River Authority’s Nekton Survey on Tuesday, Nov. 23, 2021. The survey monitors fish diversity.
Billy Calzada /Staff photographer
Aquatic biologists Austin Davis, left, and Zoe Nichols stand in the riverbed of the San Antonio River along Mission Reach as they prepare to trap fish for the San Antonio River Authority’s Nekton Survey on Tuesday, Nov. 23, 2021. The survey monitors fish diversity.
Billy Calzada /Staff photographer
Aquatic biologists Zoe Nichols, left, Austin Davis, middle, and Steve Bittner check the fish caught in their net as part of the Nekton Survey for the San Antonio River Authority on Tuesday, Nov. 23, 2021. The survey monitors fish diversity.
Billy Calzada /Staff photographer
Aquatic biologist Austin Davis carries equipment on his back that momentarily shocks fish so that they can be caught more easily to be studied as part of the Nekton Survey for the San Antonio River Authority on Tuesday, Nov. 23, 2021. The survey monitors fish diversity.
Billy Calzada /Staff photographerDavis is an aquatic biologist with the San Antonio River Authority. He and biologists Zoe Nichols and Steve Bittner are finishing a weeklong project in the river’s Mission Reach area, stretching from Southtown to beyond Stinson Municipal Airport. Today, the team is off Camino Coahuilteca, sporting full-length waders and carrying buckets, nets and Davis’ electrofisher on his back.
The project, called the Mission Reach Intensive Nekton Survey, monitors fish diversity in the San Antonio River in hopes of identifying species that are returning to the Mission Reach area after it was restored nearly a decade ago. The higher the quality and quantity of new fish that the team discovers, the better. The presence of certain fish species, especially those returning to the river, means the river’s ecosystem is healthier and the habitat is strengthening.
This is the third year the river authority has conducted the survey, and the preliminary results are more promising than ever. Two years ago, the team found 24 species; as of the current survey, the count is up to 29. Three new fish species have been found in the river: the sand shiner, golden shiner and longnose gar.
“Texas logperch is an exciting fish to find,” Nichols said. “But we’re also excited about everything. It’s good to see the restoration effort has paid off.”
A good place for fish
The Mission Reach wasn’t always so welcoming to plants and animals. After the creation of a modernized river system in the 1930s, the natural ecosystem was disrupted, displacing fish, mussels and other animals that relied on the river for survival.
Aquatic biologists Zoe Nichols, left, Austin Davis, middle, and Steve Bittner check the fish caught in their net as part of the Nekton Survey for the San Antonio River Authority on Tuesday, Nov. 23, 2021. The survey monitors fish diversity.
Billy Calzada /Staff photographerIn response, the city in 1998 began a project to restore the Mission Reach. The project, which was finished by 2013, incorporated human-made riffles, paddling chutes and native vegetation to jump-start the original ecosystem.
The fish survey is one way to analyze its success.
“We started this project to gauge ecological success and restoration,” Davis said. “This is the first year that we’ll have some adequate data to actually start looking at trends and such. We can look at how many new species we’ve been getting every year and go from there.”
This time, the team is working in the city-engineered riffles, which are shallow, fast-moving segments of the river. These areas are vital for fish. As the water rushes over rocks, it adds oxygen to the river. That keeps insects alive and healthy, living within the riffles and providing food for fish.
Also, the rocks and pebbles at the bottom of the riffles provide space for fish to lay eggs.
“The man-made riffles are embedded like boulders. They’re not going anywhere,” Nichols said. “Over time, we’ve seen some naturally forming riffles, too, which is definitely what we want to see because it’s going to just create more diversity within the Mission Reach.”
The river has a variety of habitats, each with different groups of fish. Before the riffles, Nichols and the others surveyed deeper parts of the river on a boat, which revealed larger fish species.
After catching fish in a given area, the team must check for habitat parameters, including analyzing water quality and studying the sizes and types of sediment, such as clay, silt or gravel. This part of the project helps the team better understand what kinds of habitats each species of fish lives in and which ones are producing more diversity.
This particular riffle had six species, including the Texas logperch and the Guadalupe bass, both of which have been historically scarce in the Mission Reach.
“It’s been a good day for the survey,” Davis said.
The value of new fish
The reintroduction of multiple fish species in the San Antonio River also has resounding implications for the entire ecosystem.
A Guadalupe bass is held in a net after being caught for study as part of the San Antonio River Authority’s Nekton Survey on Tuesday, Nov. 23, 2021. The fish was measured, momentarily studied and released. The survey monitors fish diversity.
Billy Calzada /Staff photographerMussels, which are also being reintroduced into the river, depend on fish to survive. Mussel larvae attach themselves to the gills of fish until they develop into young mussels — called juveniles — and detach back into the river.
A healthy and diverse fish population fosters a healthy freshwater mussel population. Some mussels prefer to attach themselves to gar, which, until this year, were hard to find in the river.
But this week, the aquatic biologists found the longnose gar for the first time. The fish provides a home for larvae of the yellow sandshell freshwater mussel, a species the river authority is looking to reintroduce into the Mission Reach also.
“In the three years doing this survey, we have only found this one gar,” Bittner said. “It was so exciting to finally catch one.”
For the team, fish are just one component of the greater, holistic restoration. Davis, who grew up in San Antonio, wants his city to be proud of its river. Since 2013, the river authority has categorized 207 varieties of bird species, while about 70,000 people have accessed and used the river since the Mission Reach restoration.
Now, people can also fish for Guadalupe bass, Bittner said, though it’s preferable that people catch and release them until their numbers increase further.
“It’s kind of like proving people wrong about the river,” Davis said. “Look at all the diversity we have. Look at the ecological health that we have. It’s supporting the life it should support.”
Elena Bruess writes for the Express-News through Report for America, a national service program that places journalists in local newsrooms. ReportforAmerica.org. elena.bruess@express-news.net
"fish" - Google News
November 27, 2021 at 05:11PM
https://ift.tt/3cWzdQZ
San Antonio River fish making a comeback - San Antonio Express-News
"fish" - Google News
https://ift.tt/35JkYuc
https://ift.tt/3feFffJ
Bagikan Berita Ini
0 Response to "San Antonio River fish making a comeback - San Antonio Express-News"
Post a Comment