Dusky darter facts for kids
Quick facts for kids Dusky darter |
|
|---|---|
.jpg) |
|
| Conservation status | |
| Scientific classification | |
| Synonyms | |
|
Hadropterus scierus Swain, 1883 |
The dusky darter (Percina sciera) is a type of freshwater fish. It's a small fish that lives near the bottom of rivers and streams. This darter belongs to the family called Percidae. This family also includes well-known fish like perches.
Dusky darters are found in the eastern, southern, and southeastern parts of the United States. They live in both large and small rivers, as well as shallow creeks. You can often find them in the Mississippi River system. These fish prefer areas where the water doesn't flow too fast. They like to hide among woody debris on sandy or rocky riverbeds.
Contents
Where Do Dusky Darters Live?
The dusky darter lives in many different freshwater places. These include creeks, streams, rivers, and even lakes and reservoirs. You can find them across the eastern United States. This includes areas like the Tennessee Tombigbee waterway and parts of Ohio. They also live in streams within the Pine Hills of Mississippi. Sometimes, different darter species, including the dusky darter, live together in the same areas. They often find ways to share resources, like different spots in the river.
How Dusky Darters Live
Their Home Sweet Home
Dusky darters can live in many different types of underwater homes. They are found in shallow, fast-moving sections of a river called riffles. They also live in deeper, slower-moving areas called pools. The bottom of their homes can be made of large rocks or a mix of sand and gravel. They often prefer spots with slow water flow. These spots are usually found where fast-moving water meets calm pools. They like to stay on top of small pieces of wood or on sandy and rocky bottoms.
What's for Dinner?
Dusky darters are carnivores, which means they eat meat. Most of them eat the young forms of aquatic insects. These include tiny midges, black flies, mayflies, and caddisflies.
When they are very young, called larvae, dusky darters are not very good at hunting. They have simple digestive systems. So, they eat very small creatures like tiny water fleas. As they grow, they can eat bigger prey. Adult dusky darters eat small creatures that live on the river bottom. These are usually less than five millimeters long. They eat more but smaller prey compared to other fish. This helps them keep their energy up. Bigger darters tend to eat bigger prey.
Who Eats Them?
Young dusky darter larvae can be eaten by tiny creatures called cyclopoid copepods. Watersnakes also eat darters. This is a common way darters die, but it's not always well-known.
Life Cycle of a Darter
Scientists have studied how dusky darters reproduce in labs. They found that these fish can grow from eggs to adults ready to spawn in just one year.
When they are one year old, male dusky darters are about 94 millimeters long. They weigh about 7.5 grams. Females are a bit smaller, around 83 millimeters long and weighing 4.9 grams. Both one-year-old and two-year-old fish can lay eggs successfully.
Dusky darters lay their eggs on fine gravel. This happens when the daylight lasts about 13 hours. The water temperature is around 19 degrees Celsius (66 degrees Fahrenheit). A female can carry up to 184 eggs. Each egg is about 1.65 to 1.78 millimeters wide. In one lab test, out of over 6,000 eggs, about 720 young darters hatched. Some darters in the Percidae family can live up to four years old.
Protecting the Dusky Darter
Many darter species in the U.S. are listed as endangered or threatened. This means they are at risk of disappearing. For example, the Amber darter has struggled because its home has changed. While the dusky darter is not federally listed as endangered, it has disappeared from North Carolina.
The biggest danger to the dusky darter is changes to its river home. These changes are caused by human activities. This includes building homes and farms, pollution from factories, and taking too much water from rivers. These activities can change how rivers look and flow. They can increase dirt buildup and water temperature. This harms the riverbed where darters live. It can make it harder for them to find food, grow, and reproduce.
Pollution from roads can also be harmful to darters and other fish. The U.S. Environmental Protection Agency says that changes to physical habitats are a big problem for fish. This is especially true in areas where fish communities are not doing well.
Protecting the places where darters live is very important. This means reducing the negative effects of human activities. For example, too much stormwater runoff from roads and parking lots can cause floods. This can damage river habitats. Setting rules for stormwater can help. These rules make sure that less rainwater runs off surfaces. Instead, it soaks into the ground.
Sometimes, breeding darters in labs can help. This is called artificial propagation. Scientists try to copy the natural conditions of the river. They use special tanks with gravel for eggs. They control light and temperature to match what darters need to reproduce.
How Scientists Watch Darter Populations
Scientists monitor dusky darter populations to make sure they are healthy. They look for areas that have the right conditions for the fish. These conditions include the right water flow, depth, and type of riverbed.
Scientists use different methods to find and count darters. One way is called seining. This involves using a large net to catch fish. Another method is electrofishing. This uses a mild electric current to temporarily stun fish. This allows scientists to catch them, measure them, and then release them safely. Snorkeling is also used to observe darters in their natural environment.
A typical team for studying fish includes four people. Two people hold the seine net. One person operates the electrofishing equipment. Another person helps with the net or kicks the water to guide fish into the net. Snorkelers look for darters by swimming slowly upstream in a zig-zag pattern. This helps them cover as much area as possible. It's important that snorkelers are never in the water when electrofishing is happening.
