NASHVILLE, Tenn. (AP) – It was a fall day when biologist Bernie Kuhajda went to an unusual stream flowing through a cow pasture in Middle Tennessee to try to prevent the extinction of a small, brightly colored fish.
The drip — little more than a few large mud puddles — was one of the last remaining bodies of water with a population of Barrens topminnows, and it was drying up.
So Kuhajda and his team pulled a large sieve through the muddy ponds and collected 64 of the tiny, iridescent killer fish to take back to the Tennessee Aquarium, where they maintain a “ship population” as a safeguard against their disappearance. wild
“If we hadn’t saved these 64, the entire genetic population of Barrens topminnows would have disappeared,” Kuhajda said. “This species would be one step closer to extinction, and now it’s not too far away.”
That was in 2016, and although these fish were saved, the fate of the species is uncertain.
The Barrens topminnow has spent more than 40 years among the endangered species — a study in which the fish’s chances of survival have suffered from acrimony during a highly publicized battle to save another small Southeast fish, the snail minnow. . The topminnow finally received federal protection in 2019, but its future is still in doubt in part because the U.S. Fish and Wildlife Service has not identified its critical habitat — the areas that must be protected for its recovery.
Over the decades, its distribution dwindled to a few springs and rivers around Manchester, home of the annual Bonnaroo music festival. During that time, it was both a victim of the political backlash against the Endangered Species Act and a beneficiary of comprehensive efforts to prevent its extinction.
One of its champions is Pat Rakes, a biologist who studied Barrens topminnow for his master’s degree at the University of Tennessee, Knoxville, and now heads the nonprofit Fisheries Conservancy. It is one of the few institutions that maintain ship populations. Rakes said there are many good reasons to protect a small fish that many people may consider insignificant, and perhaps the best is that all aquatic animals and plants work together to keep the ecosystem healthy.
As Rakes says, “If you tinker with a car, you don’t throw away any parts or put them back together.”
Barrens topminnows grow to about 4 inches (10 centimeters) and live about three years. They eat insects and small aquatic animals. Breeding males are brightly colored with a bright blue-green body with red-orange spots and blue fins with yellow and black edges.
“They are absolutely beautiful,” said Margaret Townsend. “They look like jewelry, as if they are covered with precious stones.”
Townsend is an attorney for the Center for Biological Diversity and recently threatened to sue the wildlife service for failing to designate critical habitat. The service asked for patience, writing on Sept. 7 that it is “working patiently” and expects to submit the proposed critical habitat by the end of the year.
Barrens topminnows are named for where they live—Tennessee’s Barrens Plateau, named for its relative lack of trees. Small cascades and waterfalls isolate the plateau waters, preventing downstream fish from invading topminnow territory. But in the 1960s or 1970s, Western midges were introduced in a misguided attempt to control mosquitoes—they eat mosquito larvae, but so do Barrens topminnows. Everywhere mosquitofish were brought in, topminnow disappeared.
“They eat all the topminnow eggs, all the larvae, and they chase the Barrens topminnows — even though the Barrens topminnows are bigger — and clip their fins,” Rakes said.
Recognizing the threat of habitat loss from farming and development, as well as mosquito predation, the Fish and Wildlife Service first proposed listing the Barrens topminnow as endangered in 1977. This was shortly after the Endangered Species Act was passed. It’s also been muddled in the middle of the relentless snail’s pace that has kept construction of the Tennessee Valley Authority dam going for more than two years.
The snail fight has dampened the public and political appetite to list another small Tennessee fish as endangered. Delisted, the Barrens topminnow has been occasionally reviewed in the National Register over the following decades.
In the 1990s and 2000s, the Fish and Wildlife Service signed conservation agreements with ranchers like Raymond Cooper that sought to protect the cattle from the few springs where they still live by fencing. Cooper said in a telephone interview that even though the contract had expired, he still fenced his cattle because it was the right thing to do “for the sake of the flow.”
“As far as I know, there are still topminnows hatching,” he said. “As long as I own the farm, it will be protected. But at the age of 79, I’m not going to have it forever.”
Without the efforts of biologists like Kuhajda to collect them, raise them in captivity, and release them into the wild to restore viable populations, barren topminnows may already be extinct.
Kuhajda said the fight to save the Barrens topminnow is bigger than one small fish. The American Southeast has the greatest aquatic biodiversity of any temperate world, with fish, mussels, water snails, grasshoppers and aquatic insects such as mayflies and dragonflies.
“It’s part of our natural heritage in the Southeast and most people don’t know about it,” he said. “You won’t find most of these animals anywhere else. This is something to be proud of.”