[Note: this story has been modified since its original posting to correct errors.]
It’s been six years since the endangered Topeka shiner was found in Boone County, and scientists think chances are slim that the species will ever be found naturally in local streams again.
The silver-colored minnow is an indicator species, which means its decline can foreshadow the survival of other species of fish.
“It is more sensitive to environmental change,” said Tim Grace, a fisheries management supervisor with the Missouri Department of Conservation. “A decline is really a clue that something is wrong in the area.”
Missouri's Endangered Shiners
The shiner, a federally listed endangered species, was last found in Boone County in 1997 during routine sampling in Bonne Femme Creek.
“We hope we’re wrong, but we’ve come to the conclusion that the shiner is gone from Boone County,” Grace said.
Since 2001, Bonne Femme hasn’t been monitored closely, but Grace said the department plans more sampling in the future.
The Topeka shiner is 11/2 to 2 inches long and native to Missouri. It is also found in Iowa, Kansas, Nebraska, Minnesota and South Dakota.
“Nationwide we have seen a disappearance of 90 percent of the Topeka shiners,” Grace said.
The last two known natural populations in Missouri are in Moniteau Creek in Cooper County and Sugar Creek in Daviess and Harrison counties. Until the 1960s, shiners were found in Boone County in Hinkson, Rocky Fork and Silver Fork creeks. The species was found until the 1970s in Bass Creek and Turkey Creek, two streams that flow through Three Creeks Conservation Area south of Columbia.
“It disappeared fairly fast, and we are not sure why,” said Doug Novinger a resource scientist with the conservation department. “We’re looking at a drastic decline over only a 20-year time period.”
A Mystifying Disappearance
In the 1990s, studies showed the species was in rapid decline and identified streams with remaining populations, including Moniteau Creek. Last week, Novinger and two other conservation workers sampled fish at one of 12 sites in the Moniteau Creek watershed that are surveyed each year as part of a 10-year study of the shiner.
Shane Dunnaway, a resource technician, recorded the amount of algae in the stream, the age of the trees and erosion on the banks in hopes of finding a correlation between anything in the environment and the decline of the species.
Wearing chest waders, Novinger and resource assistant John Calfee pulled a seine through the creek and recorded the types and numbers of fish. They expressed excitement at finding sunfish because Topeka shiners are usually found in the same places. When the sunfish build nests, they clean gravel, which the shiners use later for spawning.
But their net yielded only three Topeka shiners compared to 10 in this location last year. The crew had better luck at another site, where the number of shiners went from 16 last year to 70. Many are young, which means the minnow is reproducing.
Studies are being done throughout the country to better understand trends in shiner populations. In Missouri, the conservation department is looking at the effects of water quality, though it doesn’t test for chemicals or pesticides other than nitrogen and phosphorus.
“We are very concerned about the effects of runoff of fertilizers,” Novinger said. “It delivers chemicals such as nitrogen and phosphorus, in sediments, that are potentially harmful into the streams.”
Matthew Winston, a scientist with the conservation agency, also listed the proliferation of ponds as partially to blame for the loss of shiners. Ponds, he said, can introduce new predators, such as bass, into the streams.
Though predators may be part of the problem, Winston said, they are not the root cause.
“The ecology of the environment is like the ecology of the body,” he said. “If a person has AIDS, pneumonia kills them, but it is because their immune system was weakened by the AIDS. Predators may be killing the Topeka shiners, but it is because they may have been already weakened from pollution.”
While the outlook for the shiner is bleak, propagation efforts have had “remarkable success,” Novinger said. At the state’s Lost Valley Hatchery, the Topeka shiner spawns in ponds shared with orange spotted sunfish. The success is important, but Novinger said it is still imperative to have the species survive on its own.
“The disappearance of the shiner,” he said, “may impair the ecosystem in ways we can’t predict.”