Quantity/Quality/Wildlife Meeting January 5 1995

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� L � 1 Native Aquatic Wildlife Management in Colorado The Vision and Need Thomas P. Nesler Nongame & Endangered Aquatic Wildlife Program Colorado is unique among western states because the headwaters of five major river basins originate here. As such, Colorado historically provided habitat to a diverse group of aquatic wildlife species that forms our wildlife heritage. While each basin shares a large number of common wildlife species, each contains unique species that set each river basin apart from the others. Our river basins also contain a number of wildlife species at the periphery of their range, where the transition to higher elevations from our borders to the Continental Divide create a changing continuum of habitat types, less suitable for some species, more suitable for others. Today, these unique and peripheral species are most often observed to be in decline in each of our major basins, and indicate natural attributes of our aquatic habitat and Colorado's environment are being affected. As Colorado's public had expanded from its rural origins and grown more urbanized, so has its perceptions and values changed. Conservation of Colorado's wildlife is gaining increasing emphasis relative to the traditional focus on hunting and fishing recreation. The vision of the aquatic wildlife program for the Division of Wildlife is to maintain self - sustaining populations of all native aquatic wildlife in Colorado. Native aquatic wildlife in Colorado is represented by 116 species of fish, amphibians, mollusks and crustaceans. Eighty -four percent are nongame. Colorado's 120 fish species are composed of 42% native nongame species, 5% native sport fish species, and 53% introduced species. Even with over half of Colorado's fishes being introduced, only 40% of these non- native fishes are valued for sportfishery purposes. The status of our native fishes shows 61 % of our 56 species are considered to be at risk (Table 1). Fourteen percent no longer exist in Colorado or are extinct; 13 % are threatened or endangered; and 34 % are of special concern due to perceived declines or vulnerability due to low numbers and distribution. There are 3 state - listed or special concern status fish species in the Rio Grande basin, 5 in the Arkansas, 6 in the Republican, 9 in the Colorado, and 10 in the Platte. There are 2 -4 state - listed or special concern amphibian species in each of the major river basins. One mollusk species of special concern is found in the headwaters of the South Platte. The status of fifty -three percent of native amphibians, 97% of mollusks, and 100% of decapod crustaceans remains undetermined. All species of special concern are potential candidates for state or federal listing as threatened or endangered. Those species included in federal candidate lists as category 1 or 2 are the highest priority species being considered for federal listing. A predominant attribute of Colorado's native aquatic fauna is that there are real or apparent declines in many of these species' populations, which suggests the general quality of their habitat is being degraded. To achieve the vision above, only proactive conservation of wildlife at the state and local level can alter this declining trend and preclude the need for federal listing and intervention. Since the majority of the state's native species are nongame, traditional species by species management is impractical. As the species within each community are linked 01