7985 - Laserfiche WebLink

Home Browse Search

. ... ....h--tJ[;ir(1 368 The Southwestern NaluTalist vol. 38, no. 4 wild fish moved out of the reservoir into the river and seemed to survive the experience more suc- cessfully (2 out of 3 survived, compared to only 1 out of 4 hatchery fish surviving until the end of the study). There was no discernable difference in behavior between the surviving fish attribut- able to their origin. Implanting dual tags may have contributed to the unusually high (43%) mortality of the tagged fish, confounding the re- sults. Low recapture may also be attributable to the difficulty of sampling Colorado squaw fish in the size range 100 mm to 250 mm. Wild specimens are seldom collected in this size range, although recruitment into the adult size-classes occurs. The stocked fish may reappear at a larger size. In support of this is the recent recapture of adult squawfish in the Colorado River that were marked with coded wire tags and stocked as fingerlings in 1982, 1983 or 1984. Three out of 21 adult Colorado squaw fish collected during spring sam- pling in 1990 had coded wire tags, although their stocking year could not be determined without surgery (B. Burdick, pers. comm.). Not only did catch rate decline following stock- ing, but, also, total capture success in the reservoir was quite low. One percent of the total fish stocked were eventually recaptured. Only 14 fish were collected in their second year. Only four of these fish were caught in Kenney Reservoir. Five of these were collected in 1991, one in the reservoi r, three above, and one below. No squaw fish were collected in the third year after stocking. Unless the Colorado squaw fish subsequently reappear at a larger size when they are more susceptible to capture, little additional informa- tion can be gained from this stocking effort. In- cidental catch by anglers may also contribute in- formation on the fate of any surviving Colorado squawfish. Due to the small number and sizes (112 to 184 mm) of stocked fish collected in 1991, the Colorado Division of Wildlife recommended that further intensive evaluation of stocked Col- orado squaw fish be postponed until evidence is obtained, either through sampling or creel survey, that any of the stocked fish remaining in the res- ervoir are vulnerable to angling capture. The suc- cess of subsequent stockings of squaw fish might be improved by stocking larger-sized fish after runoff. Some fish loss could be prevented by mod- ification of the spillway and release procedures. Techniques employed to minimize fish escape- ment over the spillway should be explored if fu- ; I l ture stocking is planned. This strategy should include efforts to minimize the magnitude and duration of surface releases at the time of stock- ing. The concept of establishing a sport fishery for Colorado squawfish has been previously pro- posed and discussed as a recovery strategy (Wy- doski, 1982). Colorado squaw fish are attractive, silvery fish that reach trophy sizes, take lures readily, are strong fighters, and are reputed to be delectable. In short, they have air the prerequi- sites of a fine sportfish except for the regard of the anglers, and wide ranging movements that may exceed the confines of small-sized mainstem impoundments. The low return of stocked fish, regardless of the cause, does not generate much promise for establishing a sportfishery. Nor does stocking Colorado squawfish in mainstem res- ervoirs appear to be an effective mitigation pro- cedure for habitat loss due to impoundment. This research was supported by grants from the Colorado Division of Wildlife and the Sigma Delta Epsilon Graduate Women in Science. The U.S. Fish and Wildlife Service office, Grand Junction, Colorado, provided radio equipment and field assistance and ar- ranged for stocking the fish. We wish to thank Water Users Association #1 in Rangely, Colorado for their cooperation and support during this study. We wish to thank W. Wiltzius for offering helpful comments and suggestions on the manuscript. Cooperators in the Colorado Cooperative Fish and Wildlife Research Unit include the United States Fish and Wildlife Service, Colorado Division of Wildlife, and Colorado State University. LITERATURE CITED CARLSON, C, A., ET AL. 1979. Fishes and macroin- vertebrates of the White and Yampa rivers, Colo- rado. U.S. Bur. Land Mgmt. BioI. Sci. Ser., 1:1- 276 CHART, T. E., AND E. P. BERGERSEN. 1992. Impact of mainstream impoundment on the distribution and movements of the resident flannelmouth sucker (Catostomidae: Catostomus latipinnis) population in the White River, Colorado. Southwestern Nat., 37: 9-15. _. 1988. Methods for long-term identification of salmon ids: a review. U.S. Fish and Wildlife Ser- vice, Biological Report, 88:1-18. CLARK, C. F. 1942. A study of the loss of fish from an artiliciallake over a wasteweir, Lake Loramie, Ohio. North American ConL Transactions, 7:250- 256. COLORADO RIVER FISHES RECOVERY TEAM. 1988. , ",;"- '~" :.:~~, "~~:-' ~~~(~'~9~:-~B~1~~~f~~~~~~:~~~~W~~~T~~~~~~~~~gf~~~~~~~S~~S~:-~~~~~~~~~~~~}~~, '.'" ',~. . . ,"' -" ',". . " ::.-~..:. ~...: