FISH

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Description The Colorado River running through Grand Canyon once hosted one of the most distinctive fish assemblages in North America. The wild Colorado River presented fish with a challenging and variable aquatic habitat: very large spring floods, near-freezing winter temperatures, warm summer temperatures, and a heavy silt load. Note that only eight fish species were native to Grand Canyon. Of the eight species, six are endemic, meaning that they are only found in the Colorado River basin. (NPS)

Fish Species of the Colorado River in Lower Glen Canyon and Grand Canyon (See Fish Table)	TBD (TBD)	TBD (TBD)

GROUP MEMBERS No Ad-Hoc Group currently assigned 141029 USFWS HBC Down listing -Topic News AZ Daily News_ Razorback Sucker turns up in Grand Canyon after 20 years The last one recorded had been caught in 1990. Caught October 9th, lower part of Grand Canyon believed to have traveled upstream some 50 miles from Lake Mead. Whirling Disease Page Quick Facts Diet studies of Rainbow Trout and Brown Trout in Grand Canyon indicate that these species do eat native fish. Rainbow Trout are less piscivorous than Brown Trout, but there are more RBT than BRT "Brown Trout consumption rate 20 times that of Rainbow Trout..." (MYard) Rainbow and Brown Trout disporpotionately prey on native fish Warming increases the growth rates of Humpback Chubs 75% of the fish species were endemic to the Colorado River basin; this is the highest degreee of endemism of any large river basin in North America. (SDM Workshop Aug 2013) Work in progress RValdez_Talus shoreline habitat used by HBC Fish What type of fish are found in Lake Powell? 1.Endangered ◦Four types of fish that frequent the Colorado River and Lake Powell are officially endangered because of the construction of dams and introduction of non-native species: the razorback sucker, Colorado pikeminnow, humpback chub and bonytail. Native ◦In addition to the above, Lake Powell is naturally home to the bluehead sucker, flannelmouth sucker, roundtail chub and speckled dace. ◦Non-Native Bass ◦The National Park Service introduced three types of bass specifically for fishing purposes: the smallmouth bass, largemouth bass and striped bass. Other Non-Natives For Fishing ◦Other non-native species have been introduced into Lake Powell with the intent of challenging fisherman. These include walleye, rainbow trout, channel catfish, bluegill and black crappie. Problematic Non-Native ◦Though almost all non-natives are damaging to native ecosystems, the gizzard shad is causing many problems to the native and non-native fish populations because of its large size. The fish has spread throughout the lake and have no natural predators. NON-NATIVE FISH HISTORY 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 throughtout 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 occur. (NPS CFMP-EA_Pg 63) POTENTIAL THREATS: 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. "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) Should a disaster such as a landslide cut off the Little Colorado chub from the mainstem, the species could quickly become extinct -Article LINK

INFORMATION Humpback Chub Page Razerback Sucker Page Bonytail Page Trout Fishery Page GCDAMP POAHG- Historical Native Fishes of Glen and Grand Canyon Reports and Links 2015 Native and Nonnative Interactions; Factors Influencing Predation and Competition Other Stuff NPS Fish Species found in the Grand Canyon NPS Grand Canyon Vertebrate Species List NPS Grand Canyon Treatened & Endangered Species List NPS Endangered Fish Learning "NNFC will occur if necessary because it is a conservation measure required under the ESA to ensure protection of the HBC." Mitigation for the impact of implementing NNFC on resources of tribal concern is addressed under the NHPA OA for NNFC. The (HBC) juvenile abundance estimate for the mainstem at the LCR is over 2,500 fish, and is above the conservation measure trigger for nonnative fish control in the FWS biological opinion of 900.130220 AMWG Minutes