FISH

---

‎

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)

TBD (Motions)	TBD (TBD)	TBD (TBD)

GROUP MEMBERS No Ad-Hoc Group currently assigned 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 Rainbow Trout are less piscivorous than Brown Trout, but there are more RBT than BRT Rainbow and Brown Trout disporpotionately prey on native fish Warming increases the growth rates of Humpback Chubs Work in progress 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 trivutaries during the late 1800s and early 1900s. Impacts of these actions was not fully understood until later in the 20th Cetury 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 20non-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) 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)

INFORMATION GCDAMP POAHG- Historical Native Fishes of Glen and Grand Canyon Bonytail Page What type of fish are found in Lake Powell? Reports and Links NPS Comprehensive Fish Management PlanBiological Assessment NPS Fish Link Video Link- AZ Central_ National Park Service attempts to undo trout damage at Grand Canyon 130701_USFWS_ Long-Term Monitoring of an Endangered Desert Fish and Factors Influencing Population Dynamics 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 LINK: usbr/amp/amwg/mtgs/13feb20/Attach_07b| | |