FISH

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Grand Canyon was once home to eight species of native fish. Only five of these species are found in the park today. Following the completion of Glen Canyon Dam in 1963, the fish assemblage in the Colorado River in Grand Canyon has shifted to non-native rainbow and brown trout in the stretches of river closest to the dam and above the Little Colorado River. Of the canyon's native fish species, only speckled dace remain truly common in the park, and they live primarily in tributaries which retain their natural characteristics more than the Colorado River. Two species of Grand Canyon's native fish are listed under the Endangered Species Act. Humpback chub, which used to be abundant in Grand Canyon, has been listed as an endangered species since 1967. Razorback suckers are very rare in the canyon, and were listed as endangered in 1991. Grand Canyon has a very distinctive collection of native fish. All eight native species belong to only two families: minnows (Cyprinidae) and suckers (Catostomidae). Six of the eight native species are found only in the Colorado River basin. This very high percentage of endemic fish species likely results from the geographic isolation of the Colorado River system, and the highly variable natural environments, flow and temperature regimes of the river and its tributaries. The Colorado River has the lowest diversity of native fish and the highest level of endemism of any river system in North America. The river's unusual native fish assemblage is as iconic a characteristic of Grand Canyon as its towering cliffs, other endemic species such as the Grand Canyon rattlesnake, and spectacular scenery.

--	Fish Species of the Colorado River in Lower Glen Canyon and Grand Canyon - online training	--

Updates Native fish in the Grand Canyon: There are four types of fish that frequent the Colorado River and Lake Powell that are listed as endangered are the razorback sucker, Colorado pikeminnow, humpback chub and bonytail. In addition to the above, the Colorado River is home to the bluehead sucker, flannelmouth sucker, roundtail chub and speckled dace. History of non-native fish in Grand Canyon: Non-native fish species present in Grand Canyon were mostly established as a result of intentional stocking to develop sport fisheries in the Colorado River and its tributaries during the late 1800s and early 1900s. Impacts of these actions was not fully understood until later in the 20th Century when a shift to native species conservation management occurred in the NPS. Negative impacts of non-native fish and altered habitats on native fish species has been well-documented throughout the world. Over 20 non-native fish species have been documented in GCNP; However, the more common, large-bodied, species of management concern include rainbow and brown trout, common carp, channel catfish, and bullhead species, striped and smallmouth bass. These species are known predators on native fish or native fish eggs or compete with native fish species.(NPS CFMP-EA_Pg 62) (17 warmwater species, 2 coldwater species, and 1 coolwater species)--- At least 7 additional species occur in nearby or adjoining waters with potential access to the Glen Canyon Ecosystem. The fish community throughout Marble Canyon, downstream of the Glen Canyon Reach is GCNP, is dominated by non-native rainbow trout. The fish community changes near the LCR inflow near RM 60 where native species begin to predominate. (NPS CFMP-EA_Pg 63) Potential Threats: "Prior to Glen Canyon Dam, the Colorado River was dominated by highly predacious non-native channel catfish. Catfish are warm water fish...Regular flooding of the LCR may be keeping catfish out of the LCR and cold water in the Colrado River does not provide habitat for catfish or other warm water fish. Without Glen Canyon Dam chubs may have been extirpated from Grand Canyon, catfish would still be the dominant fish in the Colorado River and the LCR." (090711_Minority Report to TWG_FFF_Mark Steffen) Smallmouth Bass -- In early 2000, smallmouth bass increased dramatically in abundance in the Yampa River and Upper Colorado River. Just over a decade later, the species cannot be brought under control.

Links and Information 2016 Fish Protocol Evaluation Panel (PEP) Humpback Chub Page Razorback Sucker Page Bonytail Page Trout Page Green Sunfish Page Nearshore Ecology (NSE) website Whirling Disease Page Park Service Comprehensive Fisheries Management Plan Presentations and Papers 2016 2015 GCMRC Science Updates - Fisheries Mercury and Selenium levels in the Grand Canyon foodweb Native and Nonnative Interactions; Factors Influencing Predation and Competition Quagga Mussel Risk Assessment 2009 Surveys of fish in the Glen Canyon Dam forebay Fall Steady Flow Experiment Science Plan Other Stuff Native Fishes of Glen and Grand Canyon NPS Fish Species found in the Grand Canyon NPS Grand Canyon Vertebrate Species List NPS Grand Canyon Threatened & Endangered Species List Quick Facts 75% of the fish species were endemic to the Colorado River basin; this is the highest degree of endemism of any large river basin in North America. (SDM Workshop Aug 2013)