7361 - Laserfiche WebLink

Home Browse Search

12 potatoes, chicken bones, onion, broccoli, peas, noodles, fat, cheese, and charcoal) reflects omnivorous feeding (and scavenging behavior), as noted by others (Bailey and Harrison, 1948; Davis, 1959). There is little documentation that the proliferation of the introduced channel catfish has hastened the decline of rare and endangered Colorado River fishes in the Green and Yampa rivers. However, this species has a potential for adverse impacts by directly preying on the native fishes and by competing with them for food and space. Other studies have shown that channel catfish can negatively impact native Colorado River fishes (Marsh and Langhorst, 1988, Marsh and Brooks, 1989). Large numbers of channel catfish in canyon habitats of the Green and Yampa rivers and their omnivory suggested that the fish could reduce habitat and food availability for other fishes. Negative interactions between channel catfish and the native fishes (e.g., Colorado squawfish, Ptychocheilus Lucius; roundtail chub; humpback chub, Gila cypha; razorback sucker, Xyrauchen texanus; and speckled dace) are suggested by a common use of some foods and habitats (Tyus and Minckley, 1988) and by predation on the native fishes (Kaeding and Zimmerman, 1983; Marsh and Langhorst, 1988; Marsh and Brooks, 1989; Coon, in litt.). In addition, records of Colorado squawfish with channel catfish lodged in their throats (McAda 1983; Pimental et al. 1985);(E.J. Wick, pers. comm.) are further indication of an adverse impact of this introduced catfish. It has been suggested that conditions for the endangered Colorado squawfish might be enhanced in the Colorado River by elevating mean river temperatures (Kaeding and Osmundson, 1988). We suggest that warmer water temperatures and a longer growing season may exacerbate adverse interactions between channel catfish and endangered fishes. Andrews and Stickney (1972)