Rio Grande chub facts for kids
Quick facts for kids Rio Grande chub |
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The Rio Grande chub (Gila pandora) is a type of fish found only in the United States. It belongs to the carp family. You can find it in the upper parts of the Rio Grande and Pecos River systems. These rivers flow through Colorado, New Mexico, and Texas.
This fish is naturally found in most of these areas. However, some populations now live in places like Coyote Creek, the Mora River, and the Sapello River in New Mexico where they weren't originally. Scientists are still studying how these new populations affect the waterways. It's also thought that this fish might be native to the Canadian River in New Mexico, but this isn't proven. The Rio Grande chub can sometimes naturally breed with the Longnose dace (Rhinichthys cataractae).
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What Does the Rio Grande Chub Look Like?
You can identify the Rio Grande chub by looking at its head, eyes, tail, and size. Adult fish can grow up to 30 centimeters (about 12 inches) long. But they are usually much smaller. In Colorado, they are often around 13 centimeters (about 5 inches) long.
The Rio Grande chub has large eyes and a long head. Its tail is forked, meaning it splits into two points. Their back is usually dark, and their belly is light. The colors slowly get lighter as you move from their back to their belly. They also have two faint black lines along their sides. One line is above their lateral line (a special sensing line on fish), and the other is below it.
When these fish are ready to breed, their fins, sides, and mouth turn a yellowish color. Male chubs will show much brighter colors than females during this time.
To identify them more closely, you can count the scales along their lateral line. The Rio Grande chub has between 51 and 67 scales there. They also have 8 rays (support structures) in both their dorsal fin (on their back) and anal fin (on their belly). This fish also has 6 to 10 gill rakers, which are small comb-like structures inside their gills.
Where Does the Rio Grande Chub Live?
The Rio Grande chub likes to live in small, flowing water bodies. This includes small streams, rivers, and flowing pools. They have also been found in small lakes and ponds. Sometimes, you might even find them in human-made waterways. These can be irrigation ditches, canals, or stock ponds.
This fish prefers cool, flowing water. They also need places to hide in their habitat. Good hiding spots include undercut banks (where the bank hangs over the water), plants hanging over the water, woody material in the stream, and plants growing in the water. There's also some evidence they like areas with sandy, gravelly, or rocky bottoms. They especially need gravel and rocky areas to lay their eggs. You can find them at elevations between 7,580 and 8,400 feet. They usually live in water that is between 12 and 69 inches deep.
What Does the Rio Grande Chub Eat?
Some experts describe the Rio Grande chub as a mid-water carnivore, meaning it eats meat in the middle of the water. This fish mostly eats tiny water animals called zooplankton, insects, small crustaceans, and even young fish.
The Rio Grande chub also shows some omnivore behavior. This means they will eat a small amount of plants and detritus (dead organic material). Not much else is known about their eating habits. We don't know their specific favorite foods. Also, how their habitat, movements, or competition with other fish affect their eating is not well studied.
One study did show that Rio Grande chubs are better at catching larvae (young insects) that have smaller cases. This fish grew up alongside the Rio Grande Cutthroat trout and the Rio Grande sucker. It plays a special role in the food web of its ecosystem. There is no sign that any other fish can fill this role if the Rio Grande chub disappears.
Why is the Rio Grande Chub in Trouble?
The Rio Grande chub does not have special protection under federal laws like the Endangered Species Act. However, the US Forest Service and the Bureau of Land Management list it as a "sensitive species." This means they are worried about its future.
The number of Rio Grande chubs has dropped a lot from what it used to be. At one time, this chub was the most common fish in the Rio Grande Watershed. Now, it's estimated that their total numbers have gone down by 75 percent.
One of the biggest reasons for this decline is the introduction of other fish that are not native to the area. For example, Brook trout and Brown trout were brought into the Rio Grande watershed. They took the place of the Rio Grande Cutthroat trout as the top predators. Both of these new trout species compete with the Rio Grande chub for food. They also eat the chub. Other non-native fish like Common Carp and Northern Pike are also thought to eat the Rio Grande chub at different stages of its life.
Breaking up and destroying their habitat has also reduced the number of Rio Grande chubs. Things like dams and water diversions (where water is moved away) have split up the fish's living areas. This makes it hard for them to move around and spread to new places. Dams also stop different groups of fish from mixing their genes. Water released from dams also changes the water temperature. This has made the water colder in winter and warmer in summer than it used to be.
Some Rio Grande chub habitats have been destroyed by human actions. These include too much grazing by livestock near rivers, building roads and bridges in areas where soil easily washes away, and bad logging practices. All these things change the water chemistry and the shape of the Rio Grande chub's home, which harms the fish.
In Colorado, the Rio Grande chub is listed as a "species of concern." It's considered a top priority for conservation. The decline in Colorado is due to habitat destruction and the introduction of non-native species. Many of the chub groups in Colorado are isolated, which means they are more likely to decline further.
Efforts to help the Rio Grande chub focus on many areas. More studies are needed to understand exactly what kind of habitat this fish needs and how it lives its life. Some efforts aim to keep the natural flow of streams. This includes taking less water from their habitats and reducing the amount of dirt and sand in the water. Other efforts focus on protecting the plants that are vital for the Rio Grande chub's home. New rules are also being made to limit how much livestock can graze near rivers and to stop bad land use practices that cause erosion and add sediment to the water.
See also
In Spanish: Gila pandora para niños
