Difference between revisions of "FISH"

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'''Description'''
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[[File:Additions and Remaining Native Fishes Slide 9.jpg |thumb]]
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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.
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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)
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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.
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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.
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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.
  
 
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! style="width=33%; background:#cedff2;" | [[Table- Fish Species of the CR- GLEN and Grand| Fish Species of the Colorado River in Lower Glen Canyon and Grand Canyon]]<br>(See Fish Table)
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! style="width=33%; background:#cedff2;" | [[Table- Fish Species of the CR- GLEN and Grand| Fish Species of the Colorado River in Lower Glen Canyon and Grand Canyon]]<br>[[link/ https://www.nps.gov/grca/learn/nature/images/8ee-native-fish.jpg]]
 
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Revision as of 16:31, 28 April 2016

Additions and Remaining Native Fishes Slide 9.jpg

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
link/ https://www.nps.gov/grca/learn/nature/images/8ee-native-fish.jpg 		TBD
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News


Quick Facts

  • 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

◦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.

Fish production does not appreciably change with distance from the dam Slide 24.jpg

  • 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

Reports and Links

2015

Other Stuff
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