GILA CHUB } Gila intermedia
DESCRIPTION: The Gila chub is a small-finned, chubby, and darkly colored minnow. Males are typically smaller than females, with adult males averaging six inches in length and adult females roughly eight inches. Scales are coarse, thick, and broadly overlapped. Breeding males have red or orange on the belly and sides, with yellow on the cheeks and lips . Fins of larger breeding males may be washed with lemon yellow.
HABITAT: The Gila chub commonly inhabits headwater pools in smaller streams, springs, and desert wetlands. The fish prefers quiet, deeper waters; it also favors protective cover such as overhanging vegetation, boulders, and fallen logs.
RANGE: Historically, the Gila chub inhabited approximately 43 rivers, streams, and spring-fed tributaries throughout the Gila River basin in southwestern New Mexico, central and southeastern Arizona, and northern Sonora, Mexico. Today, only 29 populations remain, and all are small, isolated, and threatened. The fish occupies about 10 to 15 percent of its historical range.
MIGRATION: This species is nonmigratory.
BREEDING: Reproduction primarily occurs in the late spring and into summer. Spawning may occur over beds of submerged aquatic vegetation. In relatively constant spring-fed ponds, reproduction may last throughout late winter, spring, and summer — and even autumn.
LIFE CYCLE: The Gila chub probably matures during the second to third year of life. Young are active throughout the day, while larger individuals tend to be most active in the evening and early morning.
FEEDING: The Gila chub feeds mainly on aquatic and terrestrial insects and algae. Larger chubs may eat other small fish, such as speckled dace. Adults typically feed during the evening and early morning hours, while juveniles feed throughout the day.
THREATS: The primary threats facing the Gila chub are predation by and competition with nonnative fish and bullfrog species as well as crayfish; disease; and habitat destruction and fragmentation due to water diversion, dredging, recreation, roads and livestock grazing.
POPULATION TREND: The Gila chub has been extirpated or much reduced in numbers and distribution within the majority of its historical range. According to the U.S. Fish and Wildlife Service, in 2002 approximately 85 to 90 percent of the Gila chub’s habitat had been degraded or destroyed. NatureServe describes the long-term population trend of the species thus: “large decline.”
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