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<br />000180 <br /> <br />RECOMMENDATIONS AND CONCLUSIONS <br /> <br />Expansion of the "Wild Trout Introductions" study to four streams, <br />including the Animas, Blue, upper Gunnison, and Rio Grande rivers, shoti1d <br />provide an excellent test of "wild" (CRR) and domestic hatchery strain ,(TAS) <br />rainbows in natural stream conditions. The Blue River is the only true <br />tailrace fishery situation of the four study streams. <br /> <br />Thus far, we have evaluated three domestic strain rainbows, HCC, and <br />BELL strain rainbows (Tables 6 and 7) on the upper Gunnison and Rio Grande <br />rivers, as well as the Eagle Lake rainbow (ELR) on the Arkansas River <br />(Nehring 1987). Compared to the CRR strain "wild" rainbow, all three, <br />domestic strains' have been dismal failures when survival in the wild ,for <br />longer than one year is the primary evaluation criterion. However, based on <br />the' survival of the TAS strain rainbows in the Fryingpan River for mO,re than <br />4 years (Nehring 1987) and excellent survival in the Animas River 4 months <br />after stocking, I am hopeful this "domestic" TAS strain rainbow may be more <br />successful at surviving in the wild. <br /> <br />The first stocking of the CRR strain rainbow in excess 'of lO cm (4 'in.) <br />average size took'place in 1987. Thus, beginning 'in 1988 we will have the <br />first evaluation of any potential benefits of increased average size at <br />stocking using this bonafide wild rainbow stock in the Rio Grande River. It <br />is readily apparent already that the CRR strain of "wild" rainbow is far <br />superior to most "domestic" strain rainbows when it comes to long-term', <br />survival (1-3 years) in natural stream environments in Colorado. While~the <br />performance of the TAS strain rainbow has been outstanding, on the Fryingpan, <br />River (Nehring 1986, 1987), its performance in a more, natural (non-tailrace) <br />stream environment remains untested. Evaluation of the first stocking <br />(l987) of TAS rainbows in the study streams will come during the 1988-89 <br />segment. <br /> <br />Tentative conclusions about expected survival rates of ,fingerling plants' <br />in the natural stream environment are as follows. First, a 'survival rate' of <br />5-10% one calendar year after stocking seems to be a reasonable expectation <br />for rainbow fingerlings under lO cm (4 in.) total length. Secondly, poiut <br />stocking is much less effective than scatter-stocking, preferably by boat. <br />Thus, survival of boat-stocked fingerling, both rainbow and brown trout, has' <br />been far superior to point-stocking (walking) techniques on the upper <br />Gunnison, Rio Grande, and Animas rivers. These conclusions are supported by <br />the findings of others (Hume and Parkinson 1987, 1988). <br /> <br />\: !~~: }\ <" . <br /> <br />'\..;- -;-. <br /> <br />Ii I:1OQ02407 <br />