River chub facts for kids
Quick facts for kids River chub |
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| Nocomis micropogon | |
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The river chub (Nocomis micropogon) is a type of minnow. It belongs to the Cyprinidae family, which includes many kinds of freshwater fish. These fish are very common in streams across North America.
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What River Chubs Look Like
The river chub is a strong, sturdy minnow. Its back is dark olive green, and its belly is a dusky yellow color. It has orange-red fins and large scales. Its mouth is slightly underneath its snout, and it has a small whisker-like organ called a barbel at the corners of its jaw.
During the breeding season, male river chubs change their look. They get a pinkish-purple color and their heads swell up. They also grow small bumps, called tubercles, between their eyes and snout. Because of these bumps, they are sometimes called "hornyheads." River chubs can grow up to about 33 centimeters (13 inches) long. Males are usually bigger than females. A common length for them is about 13.5 centimeters (5.3 inches).
Where River Chubs Live
River chubs are one of the most common fish in North American streams. You can find them mostly around the Great Lakes and in the Appalachian Mountains region. They like clear, medium to large creeks and rivers. These places usually have a moderate to fast current and rocky or gravel bottoms.
Their home range stretches from southeast Ontario and southern New York all the way to Michigan and Indiana. They also live south to northwest South Carolina and northwest Alabama. This includes big river systems like the Susquehanna River and Ohio River. Sometimes, they are found in new places because fishermen empty their bait buckets there.
Most people think river chubs are widespread and doing well. However, in some places, they are facing problems. For example, in Illinois, they are in critical danger in their small area of the Wabash River. In Alabama, they are considered at risk, and in Georgia, they are vulnerable. In Ohio, they have disappeared from some western areas due to cloudy water and siltation (when dirt settles at the bottom). They are also threatened by acid mine drainage in coal mining areas. Also, dams can block off parts of their habitat, which reduces where they can live.
What River Chubs Eat and How They Help
River chubs are food for bigger fish. Fishermen also use them as bait to catch larger game fish like bass and catfish. River chubs mainly eat small creatures that live in the water. One study found that insects made up most of their diet. They also ate plants, tiny organisms, small crabs, and snails. Caddisfly larvae and fly larvae were some of their favorite foods.
The presence of river chubs in a stream is a good sign of healthy water. They don't do well in polluted or cloudy water. They need water with a pH of at least 6.0.
River chubs also help freshwater mussels. Mussels release tiny larvae called glochidia. These larvae attach to the gills of river chubs, where they grow into young mussels before dropping off. It's thought that river chubs might even eat the jelly-like masses where these larvae are released. River chubs are hosts for several types of mussels, including some endangered ones.
Other minnow species sometimes build their nests near river chub nests. This might be because they don't have good places to lay their own eggs. Some even need the river chub's pebble nests to reproduce. For example, a type of minnow called Chrosomus cumberlandensis was helped to spawn by adding fluids from a male river chub. This shows how important river chubs are to other species in their habitat.
River Chub Life Cycle and Reproduction
River chubs can live up to 5 years. They become ready to have babies when they are two years old. In late spring, the male river chub builds a special pebble nest. He usually builds it close to the stream bank where the current is not too strong.
Females lay about 500 to 1000 eggs. They might spread their eggs among several different male nests. These pebble nests are also used by other minnow species for laying their eggs.
In early spring, the adult male river chub gets ready for breeding. His head swells, and he grows many small bumps from his eyes to his snout. Small bumps also appear on his pectoral fins, and his body turns a pinkish-purple color. When the water temperature is right (between 16 and 19 degrees Celsius), he finds a spot in the stream, usually about 0.5 to 1 meter (1.6 to 3.3 feet) deep.
He starts building his nest by making a shallow dip about 0.5 to 1 meter wide. He picks up stones with his mouth and moves them to the sides. Then, he gathers up to 10,000 pebbles, each about 1 centimeter (0.4 inches) in size. He can carry these pebbles from as far as 25 meters (82 feet) away! He builds a short platform and then a circular mound that is 20 to 30 centimeters (8 to 12 inches) high. This mound has a dip in the middle on the upstream side.
When a female ready to lay eggs enters this dip, the male presses her against the side. He fans the nest with his fins and protects it from other males by head-butting them or swimming in circles.
The eggs hatch in about 5 to 6 days. The baby fish, called larvae, grow into juveniles about 19 millimeters (0.75 inches) long in about 57 days. By two years old, a river chub is about 95 to 110 millimeters (3.7 to 4.3 inches) long and can reproduce.
Males grow faster and get larger than females. For example, a typical four-year-old male might be about 18 centimeters (7 inches) long, while a female of the same age might be about 13 centimeters (5 inches).
Protecting River Chubs
River chubs are very common in their home range. However, about 20% of North American minnows are considered at risk. None of the endangered minnows build nests like the river chub does.
The main dangers to river chubs are pollution, cloudy water (siltation), and habitat loss, especially from building dams. Like many minnows, they need flowing water over rocky or gravelly areas to reproduce. Dams can stop this flow and prevent new gravel from reaching the areas below them. While some fish struggle with this, river chubs are often still able to find gravel to build their nests.
River chubs do suffer in places with pollution, cloudy water, or acid from mines. They have disappeared from some areas in western Ohio because of too much cloudy water. Planting trees and plants along stream banks (called riparian buffers) in farming areas can help keep water clean. In Pennsylvania, a creek called Swatara Creek had no fish because of acid mine drainage. After people treated the acid and built wetlands, the river chub was one of the first fish species to return!
