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Pahranagat roundtail chub
(Gila robusta jordani) |
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| Class: |
Actinopterygii |
| Order: |
Cypriniformes |
| Family: |
Cyprinidae |
| Genus: |
Gila |
| Species: |
robusta |
| Subspecies: |
jordani |
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| Length: |
10 to 20 inches |
| Lifespan: |
7+ years |
| Feed: |
aquatic insects, and to a lesser extent on fishes and other vertebrates |
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| Habitat: |
Colorado River and its larger tributaries in the upper Colorado River basin |
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Official Status: |
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Endangered |
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Life History: |
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The roundtail chub is a member of the minnow family Cyprinidae. Roundtail chub are streamlined, similar to trout in appearance, and characterized by a robust body and tail, are olive gray in color, with silvery sides and a white belly. The roundtail chub matures at about 2-3 years of age and likely lives about 7 years or more. Breeding males develop red or orange coloration on the lower half of the cheek and at the bases of paired fins. Individuals may reach 19.3 in but usually average 9.8 - 11.8 in. Spawning occurs in the late spring; females broadcast about 2,000 tiny sticky eggs over a gravel and cobble bottom. Transparent larvae .3 inches in length hatch in 5 days and grow to about 3 inches in one year. They are omnivores, feeding mostly on aquatic insects, and to a lesser extent on fishes and other vertebrates. |
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Distribution and Habitat: |
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Historical: Found throughout the Colorado River basin from Wyoming to Arizona and likely into Mexico, and in the mainstem and most large tributaries. Roundtail chub of the lower Colorado River Basin DPS were historically found in the mainstem and many perennial tributaries of the Colorado, Little Colorado, Bill Williams, Gila, Verde, Salt, San Francisco, San Pedro, and Zuni rivers in Arizona, New Mexico and also possibly in Mexico.
Current: The species is common to rare in the mainstem Colorado River and its larger tributaries in the upper Colorado River basin.
Roundtail chub occur in cool to warm water over a wide range of elevations in rivers and streams throughout the Colorado River basin, often occupying open areas of the deepest pools and eddies of mid-sized to larger streams. Roundtail chubs are often associated with areas of cover in the form of boulders, overhanging cliffs, undercut banks, or vegetation. |
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Threats: |
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a combination of habitat loss and degradation related to dams, diversions, groundwater pumping, mining, development, recreation, improper livestock grazing, and competition and predation from non-native fishes |
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Actions / Current Information: |
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