Slender madtom facts for kids

Quick facts for kids Slender madtom
Conservation status
Least Concern (IUCN 3.1)
Scientific classification

The slender madtom (scientific name: Noturus exilis) is a type of catfish. It belongs to the Ictaluridae family, which includes other fish like bullheads and channel catfish. This fish is often found in the central part of the Mississippi River basin. It is especially common in streams within The Ozarks.

Slender madtoms live west of the Mississippi River in places like Oklahoma, Arkansas, and Missouri. They can be found as far north as southern Wisconsin and Minnesota. East of the Mississippi, they live in the higher lands of Alabama, Tennessee, and Kentucky.

These fish were first described by E. W. Nelson in 1876. Slender madtoms are usually small, less than 3.5 inches (90 mm) long. They have a flat head, small eyes, and dark stripes on their fins. Other fish, like the Noturus flavus and Noturus nocturnus, look quite similar to the slender madtom.

Slender madtoms prefer small to medium-sized streams. They like areas with fast-moving water (riffles) and calm pools. They often live where the stream bed has coarse gravel or flat rocks. Having a large rock or other hiding spot is very important for them.

Where Slender Madtoms Live (Distribution)

Slender madtoms live in two main areas called the Central Highlands. One area is in the Ozark Highlands. This stretches from eastern Kansas and Oklahoma to southern Illinois. It includes most of Missouri and northwest Arkansas. The other area is in the Eastern Highlands. This covers middle Tennessee, parts of southeastern Kentucky, and northern Alabama and Mississippi.

You can also find smaller groups of slender madtoms in Iowa, Illinois, and southern Wisconsin and Minnesota. Sadly, the number of slender madtoms has gone down in many places. Their homes have changed, especially in small streams in the Tennessee area. This means they might disappear from Mississippi.

In the northern parts of their home range, like Wisconsin, their numbers have also dropped. This is mainly because of farm water runoff and changes in river flow from dams. Dams and changes to river channels have likely made their living areas smaller.

What Slender Madtoms Eat and Who Eats Them (Ecology)

The slender madtom's diet includes many small water insects. They eat midges, mayflies, caddisflies, and tiny crustaceans. Most of their food comes from mayfly larvae and midge larvae.

Smallmouth bass are known to hunt slender madtoms. This might be why slender madtoms are more active at night. They hide during the day when these visual hunters are looking for food. Other creatures like the virile crayfish (Orconectes virilis), central stoneroller (Campostoma anomalum), and rainbow darter (Etheostoma caeruleum) sometimes eat their eggs.

Slender madtoms and the orangethroat darter (Etheostoma spectabile) often eat the same types of food. Slender madtoms live in rocky areas of creeks and small rivers. They spend most of the day hiding under big rocks. At night, they come out to find food. They prefer to feed after sunset and before sunrise.

Sometimes, slender madtoms are found in areas with lots of plants or in calm backwaters during late summer. They can live in streams where the water moves at speeds from 3 to 36 inches per second (8–92 cm/s). They are usually found at depths between 2 and 16 inches (5–42 cm). Slender madtoms are not strong swimmers. This has made it hard for them to spread to new places over time.

Slender Madtom Life Cycle (Life History)

Slender madtoms usually reproduce from mid-June through July. This happens when the water temperature is between 74 and 84 degrees Fahrenheit (23.5–29 °C). Large rivers like the Missouri and Mississippi often have a lot of silt. This silt can cover the gravel and rocks that madtoms need for nesting and hiding during the day.

They usually make their nests in small spaces dug under large rocks, often in calm pool areas. A nest can hold between 27 and 74 eggs. The male fish guards the eggs until the young fish hatch and absorb their yolk sac. The eggs hatch in about eight to nine days if the water is around 77 degrees Fahrenheit (25 °C).

Young slender madtoms grow quickly. By three weeks old, they are half the size of a one-year-old fish. They grow the most during the summer, especially in their first two years. In winter, their growth almost stops. Female slender madtoms can lay eggs in their first summer. This is true if they reach a certain size, about 2 inches (50 mm) long. Males, however, do not breed until they are two years old.

Slender madtoms are usually 3 inches (7.6 cm) or less in size. The biggest ones can be about 4 inches (10 cm) long. They can live up to 5 years, but most are found to be between 1 and 3 years old. Adult slender madtoms do not travel far. Their poor swimming skills might be why there are two separate groups of this species.

Protecting Slender Madtoms (Current Management)

The number of slender madtoms has been going down since the late 1970s. In Wisconsin, they are almost gone, even though they used to be more common there than in Minnesota. Reasons for their decline include dirt and cloudy water from farming areas. Also, hydropower operations can remove water from their habitats.

Poor farming methods near streams can add dirt and too many nutrients to the water. This makes the ecosystem unhealthy for slender madtoms and other species. Human activities have harmed the homes and lives of these fish. Being eaten by other animals and competing for food can also affect their survival.

The Minnesota Department of Natural Resources has checked streams. However, they have found very few slender madtom fish. There has not been a full count of their population across the country. The slender madtom is listed as endangered in Mammoth Cave National Park. It is also endangered in Wisconsin.

Currently, not much is being done to protect the slender madtom from pollution and other harmful things. Some state groups have checked streams for them. But, no clear plan has been made to manage or protect them. More research is needed to find the best ways to create new homes for them or fix their old ones. This would help the slender madtom survive for many years to come.

See also

In Spanish: Noturus exilis para niños