7339 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I 3-1 3.0 HISTORY AND CURRENT SPECIES STATUS The endangered main stem fishes of the Colorado River are the Colorado squawfish, humpback chub and bony tail. The razorback sucker is also often considered a target fish, but its status as a candidate species precludes immediate protection from the Endangered Species Act of 1973 (ESA), as amended. All four fi sh species have been successfully propagated in a hatchery, even though their introduction into the program has come at different times and often foll owed different modes of development. The following is an assessment of developments in hatchery propagation for each of the four speci es. The contrast in development and use of hatchery propagati on between the three "endangered" speci es (Colorado squawfish, humpback chub, bony tail) and the "candidate" species (razorback sucker) lends some valuable insight into the role of the hatchery program in the ESA. An unlisted species may be more easily distributed from the hatchery to the wild than a listed species, although federal funding for hatchery propagation of an unlisted species may not be as available. 3.1 Colorado Squawfish 3.1.1 Brief History Colorado squawfish fry were first produced in a hatchery in July 1974 from 7 of 8 adults transferred in July 1973 from the Yampa River to the Willow Beach NFH in Arizona (Toney 1974). This first brood stock yielded 5000 to 10,000 young squawfish using spawning, hatching and rearing methods similar to those used with other warm-water fishes. An additional 14 wild adults were transferred to Willow Beach NFH from the Colorado River on November 18, 1975; 8 were transferred from the Green River near Jensen in May 1976; 11 from the Colorado River near Grand Junction on April 24, 1978; 11 from the Green River near Jensen in May 1978; 3 from the Green Ri ver near Jensen in October 1979; and 4 from the Colorado Ri ver near Moab on November 2, 1979 (Hamman 1981b). Thirteen of these wild adults were transferred to Dexter NFH in September 1981. About 100 progeny of the wild brood fish spawned at Willow Beach NFH in 1974 were transferred to Dexter NFH in March 1980. Also transferred were the last two remaining wild females of the original broodstock. These fish were held in a 2 surface acre pond and given pelleted trout food supplemented with forage fish. The remaining five original brood fish were, unfortunately, lost in a theft of the fish at Willow Beach NFH. Reproductive success varied with Colorado squawfish from 1981 to 1984 (Table 1), because of the varied rearing conditions and propagation methods used. Hatchery-produced squawfi sh have been di stri buted to several other hatcheries, universities, research facilities and have been released in the wild at three locations.