Ashy darter facts for kids
Quick facts for kids Ashy darter |
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The ashy darter (Etheostoma cinereum) is a type of freshwater fish. It's a darter, which belongs to the subfamily Etheostomatinae. This group is part of the family Percidae, which includes perches and pikeperches. The ashy darter is found only in the eastern United States. This means it is endemic to that area.
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Where Ashy Darters Live
In the past, ashy darters lived in many parts of the Cumberland and Tennessee River areas. Many groups of these fish likely disappeared because of human activities before they were even discovered. Today, the remaining groups are spread out and rare. You can find them in parts of the Cumberland, Duck, and Tennessee River systems.
As their numbers dropped, only five river systems still had them. They are now thought to be completely gone from Virginia, Georgia, and Alabama. However, in 2004, a group called Conservation Fisheries in Knoxville, Tennessee, confirmed they still exist in Virginia.
Important groups of ashy darters live in the Buffalo and Duck Rivers in Tennessee. They are also found in the Rockcastle and Big South Fork of the Cumberland Rivers in Kentucky. Over the last 30 years, some darters have also been found in the Clinch and Elk Rivers in Tennessee. Sadly, their numbers have greatly decreased in the Little River of Blount County, Tennessee, where they used to be common.
Why Ashy Darters Are Declining
It's often hard to figure out why fish like the ashy darter are disappearing. Many things can cause their decline. Most of these problems are caused by people. For example, pollution comes from cities, farms, mines, and logging. This type of pollution is called "nonpoint" pollution. It's hard to trace where it comes from, which makes it difficult to fix.
This pollution can lead to a lot of siltation. Siltation is when fine dirt and mud build up in the water. This destroys the sandy and gravelly places where darters like to live. Another big problem is impoundments, like dams. Dams have changed rivers and streams a lot over the last 100 years. They block the fish from moving freely.
What Ashy Darters Eat
Scientists have looked at the stomachs of ashy darters. They found that these fish eat tiny insects and worms. Their diet includes midges (chironomids), mayflies (ephemeropterans), and aquatic worms (oligochaetes). They also eat small crustaceans like amphipods and isopods.
We don't know a lot about their exact eating habits. However, their special lips and long snouts might help them find prey buried under the sand or gravel. What they eat can also change depending on where they live and how old they are. For example, adult darters prefer worms and burrowing mayflies. Younger darters, which are smaller, mostly eat midge larvae.
Ashy darters need specific places to live. Because of pollution and dams, it's hard for them to find these places. They need shallow areas with sand and gravel. These spots are becoming very rare. This makes the remaining groups of darters isolated and scattered.
Ashy Darter Life Cycle
Ashy darters usually lay their eggs from late January to April. The busiest time for breeding is in April. Female darters can lay between 50 and 250 eggs each year. They become ready to breed when they are about 50 millimeters (2 inches) long. This usually happens during their first full breeding season.
Females are known to lay their eggs on water willow plants and on the edges of large rocks. Adult ashy darters can grow up to 100 millimeters (4 inches) long. They can live for a relatively long time, up to four years.
Protecting Ashy Darters
The ashy darter is currently listed as threatened in Tennessee. This means its numbers are low and it could become endangered. It's a "species of special concern" in Kentucky and Virginia. The American Fisheries Society lists it as endangered, meaning it's at high risk of disappearing. It's considered extirpated (completely gone) from Georgia and Alabama.
The National Park Service protects some ashy darter groups. These include populations in the Big South Fork of the Cumberland River and in the Emory and Obed River systems.
Organizations like Conservation Fisheries in Knoxville, Tennessee, are working to protect ashy darters. Since 2007, their biologists have collected darters from the Clinch River to try and breed them. We don't know much about how these fish live and reproduce. Because of this, breeding them in captivity has not been very successful. There isn't much money available for these efforts right now. However, scientists are looking for good places to release these fish in the future. This could help bring the species back.
Experts suggest that we need to immediately reduce the amount of silt and pollution in the water. This pollution comes from farms, cities, and sewage. In the Elk River, water levels below the Tims Ford Dam go up and down a lot. This has harmed the darters' lives and habitats. So, water levels should be kept more stable in this area. Dams also stop fish from moving to new areas and repopulating.
What we do now and in the near future will decide if the ashy darter survives. Many studies show that these darters are in great danger. They need help right away to have a chance at recovery.
Scientists have found that using small nets in large pools is a good way to collect these fish. They place nets parallel to the shore in water about 1.5 meters (5 feet) deep. Then, they move towards the shore to catch fish hiding under rocks. Studies also suggest that most ashy darter groups are at risk of disappearing from just one big disaster. So, it's very important to keep watching and monitoring the remaining groups. More surveys are especially needed for several rivers in Tennessee, like the Emory River and Upper Duck River.
Loss of habitat has caused ashy darter groups to become separated. They have also disappeared from places where they used to live. Scientists have studied the genetic differences between the remaining groups in the Cumberland, Duck, and Tennessee River systems. They found that these groups are genetically different. This means they should be managed as separate groups. When breeding and reintroducing darters, the fish should come from within these main groups. It's important to avoid mixing different genetic types. So, bred fish should be released into their original river systems, but away from existing groups.
Later studies found even more genetic differences in the ashy darter. The darters in the Cumberland River system were so different that they were named a new species: Etheostoma maydeni, or the redlips darter. The redlips darter looks different from the ashy darter because it has clear red lips. There are also differences in their fins and scales. The redlips darter grows slower and relies more on burrowing insects like mayflies. Even with all these studies, scientists are still working to fully understand the different types of ashy darters.
Gimenez Dixon, M. 1996. Etheostoma cinereum. 2006 IUCN Red List of Threatened Species. Downloaded on 4 August 2007.
See also
In Spanish: Etheostoma cinereum para niños
