8123 - Laserfiche WebLink

Home Browse Search

- Conditioning Trials of Captive-Reared Endangered Fish Before They are Stocked to Increase Their Survival in the Wild C. Long-Term Endangered Fish Needs. Long-term endangered fish needs involve augmentation and restoration stocking efforts. These needs could not be identified with certainty. However, some proposed long-term needs are ' identified below that provides some insight into these Program requirements. B ti d fi h th b i ill ecause cap ve-reare n w as s at are stocked into the upper become part of the ecosystem, all augmentation and restoration stocking should be made through experimental studies that will be thoroughly evaluated for about 5 years after stocking and used as a basis for ' preparing future stocking plans. The Biology Committee agreed that all augmentation and restoration stocking would be conducted as field experiments that would be thoroughly evaluated. Several attempts were made by Program participants to identify long-term needs for captive- reared endangered fish. The following long-term needs have not been proposed through formal Program stocking plans, have not been cleared through Section 7 consultation under the Endangered Species Act, and are ' not covered by a Federal Fish.and Wildlife Permit. See Section VII.A. of this plan regarding stocking guidelines. 1. Augmentation Stocking of Razorback Suckers in Colorado Waters Study 1 - This study will evaluate the survival of three sizes of ' razorback suckers: 4-inch, 8-inch, and 12-inch fish (Table 17). Larger numbers of fish will be required at the smaller sizes because survival is expected to be lower and sampling is more difficult for small fish. Therefore, this study will be done as three experiments: Experiment 1 will require 300,000 4-inch razorback suckers to be stocked in three river reaches (Gunnison River near Delta CO; Upper Colorado River Palisade to Loma CO]; and Upper Colorado River [Rifle to De Beque CO]). Experiment 2 will require 75,000 8-inch razorback suckers to be stocked in the same three river reaches. Experiment 3 will require 18,000 12-inch razorback suckers to be stocked in the same three river reaches. 2. Augmentation Stocking of Larval Razorback Suckers into Flooded Bottomlands in Utah Waters Utah has identified the need for razorback sucker fry to be stocked ' into flooded bottomlands that would serve as nursery areas for these fish. This stocking would be part of an evaluation of enhanced habitat in flooded bottomlands to determine the importance of these ' areas as nursery sites. The numbers of larvae needed for the experiments have not been identified. Fry production for this study 42