Difference between revisions of "GCDAMP RAZU Fish"

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==Scientific Review Suggests Reclassification of the Razorback Sucker from Endangered to Threatened - October 4, 2018==
 
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DENVER —The razorback sucker, a native fish found in the Colorado River basin is making a comeback thanks to the work of conservation partnerships between the U.S Fish and Wildlife Service (Service), states, federal agencies, Tribes, industry and environmental groups. The Service recently completed a species status assessment (SSA) and a 5-year status review, utilizing the best available science, that concluded the current risk of extinction is low, such that the species is no longer in danger of extinction throughout all of its range. The SSA explained that large populations of adults have been re-established in the Colorado, Green, and San Juan Rivers. Populations are also present in Lake Powell, Lake Mead, Lake Mohave and Lake Havasu. As a result, in the future the Service proposes to reclassify the fish from endangered to threatened.
 
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The razorback sucker is the second of the four native Colorado River fish to be proposed for a change in status from endangered to threatened this year. The humpback chub has also been proposed for reclassification.  The recovery success of these two fish would not have been  possible without the strong partnerships and conservation efforts all along the river. 
 
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“Our partners along the Colorado River have restored flow, created habitat, removed nonnative predators, and reestablished populations across these species range,” said Tom Chart, Director of the Upper Colorado River Endangered Fish Recovery Program. “These partnerships have improved conditions, proving long-term commitments are a key component to recovery.”
 
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The razorback sucker was first documented in the Colorado River system in 1861 and historically occupied an area from Wyoming to Mexico, often travelling hundreds of miles in a single year. The species gets its name from the bony keel behind its head, which helps it stay put when flows increase. Razorback sucker are part of the lake sucker family, preferring low-velocity habitats, in either backwaters, floodplains or reservoirs and evolved in an ecosystem with one large-bodied predator: the Colorado pikeminnow. Young razorback sucker have few defense mechanisms, making them vulnerable to predation , especially from toothed nonnative predators. Changes in river flows and introduction of nonnative fish caused dramatic population declines. Thanks to intense management efforts, razorback sucker have made a remarkable comeback, especially in the Green and Colorado rivers. In the Green River in the mid-1990’s, the number of adults captured in a year could be counted on one hand; today, the population has rebounded to over 30,000 adults. The large populations are the result of successful hatchery programs. Stocked fish not only survive in the wild, but migrate, colonize new areas, return to historic spawning bars, and produce viable young.
 
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Although this native fish is making a big step toward recovery, continued management efforts are needed to help the species cross the final threshold of being able to survive in sufficient numbers to reach adulthood.  The Lake Mead population is the only population where juvenile fish routinely grow up into adults. All other populations are maintained through stocking efforts as the young are eaten by nonnative fish before they reach adulthood. Scientists are hard at work to determine the best ways to encourage survival of juveniles to naturally sustain the population. One wetland along the Green River managed for razorback sucker has produced over 2,000 young-of-year individuals in the past five years, the first substantial number of juveniles seen in over 30 years in the upper basin.
 
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State, tribal, federal, and private stakeholders work together via the Upper Colorado River Endangered Fish Recovery Program, the San Juan River Recovery Implementation Program, and the Lower Colorado River Multi-Species Conservation Partnership to stock fish, create habitat, and continue monitoring programs to reduce threats to this species’ recovery.
 
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In the 5-year review, the Service also recommends that the species recovery plan be revised to incorporate the best available scientific information on the species needs and actions that will eventually allow the Service to delist razorback sucker. Efforts to propose reclassification and to revise the recovery plan will be ongoing in the coming year.  The proposed reclassification rule and the revised recovery plan will be made available for public comment in the future.
 
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*Larvae collected as far upstream as Havasu Creek [https://www.usbr.gov/uc/rm/amp/twg/mtgs/18jan25/AR19.pdf]
 
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*Radio-tagged adult migrated upstream from Diamond Creek to just below Bright Angel Creek (2016) [https://www.usbr.gov/uc/rm/amp/twg/mtgs/18jan25/AR19.pdf]
 
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*[http://biographic.com/posts/sto/in-search-of-suckers High Country News: Canyon’s depths—but will the razorback sucker stick around?]
 
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*[http://azdailysun.com/news/local/razorback-sucker-turns-up-in-grand-canyon-after-years/article_c394491f-3afa-5ff7-870d-a5aa5cdb90c1.html?comment_form=true AZ Daily News: Razorback Sucker turns up in Grand Canyon after 20 years]
 
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**The last one recorded had been caught in 1990.
 
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**Caught October 9th, lower part of Grand Canyon believed to have traveled upstream some 50 miles from Lake Mead.
 
  
 
==Status and distribution==
 
==Status and distribution==
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*[[Media:Razorback Sucker- LStevens.m4a|Audio]]
 
*[[Media:Razorback Sucker- LStevens.m4a|Audio]]
 
*[[Razorback Sucker- EP| Script ]]
 
*[[Razorback Sucker- EP| Script ]]
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*Larvae collected as far upstream as Havasu Creek [https://www.usbr.gov/uc/rm/amp/twg/mtgs/18jan25/AR19.pdf]
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*Radio-tagged adult migrated upstream from Diamond Creek to just below Bright Angel Creek (2016) [https://www.usbr.gov/uc/rm/amp/twg/mtgs/18jan25/AR19.pdf]
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*[http://biographic.com/posts/sto/in-search-of-suckers High Country News: Canyon’s depths—but will the razorback sucker stick around?]
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*[http://azdailysun.com/news/local/razorback-sucker-turns-up-in-grand-canyon-after-years/article_c394491f-3afa-5ff7-870d-a5aa5cdb90c1.html?comment_form=true AZ Daily News: Razorback Sucker turns up in Grand Canyon after 20 years]
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**The last one recorded had been caught in 1990.
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**Caught October 9th, lower part of Grand Canyon believed to have traveled upstream some 50 miles from Lake Mead.
  
 
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Revision as of 12:54, 14 March 2019

RZBS lcrmscp.jpg Razorback distribution (1).jpg

Razorback sucker (Xyrauchen texanus)

Three to 5 million years ago, a unique-looking fish with a sharp-edged hump “razorback” behind its head swam the Colorado River and its tributaries. The razorback sucker is an endangered, native fish of the Colorado River and the only member of the genus Xyrauchen. It has a dark, brownish-green upper body with a yellow to white-colored belly and an abrupt, bony hump on its back shaped like an upside-down boat keel.

One of the largest suckers in North America, the razorback sucker can grow to 3 feet in length and can live for more than 40 years. Razorback sucker can reproduce at 3 to 4 years of age. Depending on water temperature, spawning can occur as early as November or as late as June. In the Upper Colorado River Basin razorback sucker typically spawn between mid-April and mid-June. Razorback sucker eat insects, plankton, and plant matter on the bottom of the river.

To complete its life cycle, the razorback sucker moves between adult, spawning, and nursery habitats. Spawning occurs during high spring flows when razorback sucker migrate to cobble bars to lay their eggs. Larvae drift from the spawning areas and enter backwaters or floodplain wetlands that provide a nursery environment with quiet, warm, and shallow water.

Research shows that young razorback sucker can remain in floodplain wetlands where they grow to adult size. As they mature, razorback sucker leave the wetlands in search of deep eddies and backwaters where they remain relatively sedentary, staying mostly in quiet water near the shore.

In the spring, razorback sucker return to the spawning bar, often quite a long distance away, to begin the life cycle again.[1]

Razorback suckers in Grand Canyon

The razorback sucker was thought to be extirpated, or locally extinct, from Grand Canyon until 2012 when several adult razorback suckers were captured in the western Grand Canyon during surveying work. Prior to these occurrences, razorback suckers were last found in Grand Canyon more than 20 years ago. Recently, they have been found spawning in the Colorado River inflow at the upper end of Lake Mead. The National Park Service is currently planning studies to determine the status of the species in Grand Canyon.

Prior to the constructions of dams on the Colorado River and other human-caused alternations to their habitat, razorback suckers were widely distributed in the Colorado River and its major tributaries, and were typically found in calm flat-water reaches. There are at least ten historical records of razorback suckers caught in Grand Canyon, including a specimen caught in Bright Angel Creek in 1944. Today, the largest population, and possibly only population of wild reproducing razorback suckers, is in Lake Mead.

The species was listed as endangered in 1991. Critical habitat, including all of Grand Canyon National Park, for the species was determined in 1994.[2]

Online training
Fish Species of the Colorado River in Lower Glen Canyon and Grand Canyon
Fish photos, information, and maps

Updates

Status and distribution

  • Listed as endangered and given full protection under the Endangered Species Act in 1991.
  • Endangered under Colorado law since 1979.
  • Protected under Utah law since 1973
  • Historically, the razorback sucker was widespread and abundant in the Colorado River and its tributaries.

Today all populations of razorback sucker are supplemented with stocked fish except for the Lake Mead population. Lakes Mead and Mohave are the only population with wild fish.[3]

Working to recover the species

Actions being taken to recover the razorback sucker include:

  • Managing water to provide adequate instream flows to create beneficial water flow
  • Constructing fish passages and screens at major diversion dams to provide endangered fish with access to hundreds of miles of critical habitat
  • Restoring floodplain habitat
  • Monitoring fish population numbers
  • Managing nonnative fishes

In addition, the Recovery Program works to reestablish naturally self-sustaining populations of razorback sucker through propagation and stocking. The Recovery Program maximizes the genetic diversity of wild broodstock used to produce fish in hatcheries to increase the likelihood that stocked fish can cope with local habitats.

In the Upper Colorado River Basin, razorback sucker are raised at two units of the Ouray National Fish Hatchery: the Grand Valley Unit in Grand Junction, Colorado, and the Ouray Unit in Vernal, Utah.

Razorback sucker raised at these facilities are stocked in the Colorado, Green, and Gunnison rivers. Efforts to reestablish populations through stocking demonstrate success as stocked fish survive to sexual maturity and reproduce. Fish stocked in the Colorado and Green rivers have been recaptured in reproductive condition and often in spawning groups. Captures of larvae in the Green and Gunnison rivers document reproduction and their survival through the first year is evidenced by subsequent captures of juveniles.

Stocked fish are moving between the Green, Colorado, and Gunnison rivers. This exchange of individuals between rivers suggests that razorback sucker may eventually form a network of populations or subpopulations.[4]

Recovery goals

Razorback sucker will be considered eligible for downlisting from “endangered” to “threatened” and for removal from Endangered Species Act protection (delisting) when all of the following conditions are met:

  • Self-sustaining fish populations reach the required numbers in areas of the Green River subbasin and EITHER the Colorado River subbasin or San Juan Rivers, and the Lower Colorado River Basin, and a genetic refuge is maintained in Lake Mojave as identified in the chart below.
  • The threat of significant “fragmentation” of the population has been removed. (Fragmentation refers to separation between fish populations caused by geographical distance or physical barriers.)
  • Essential habitats, including primary migration routes and required stream flows are legally protected.
  • Other identifiable threats that could significantly affect the population are removed.

Downlisting Criteria
Over a 5-year monitoring period:

  • Maintain reestablished populations in Green River subbasin and EITHER in upper Colorado River subbasin or in San Juan River, each > 5,800 adults
  • Maintain established genetic refuge* of adults in Lake Mohave
  • Maintain two reestablished populations in lower basin, each > 5,800 adults

Delisting Criteria
For 3 years beyond downlisting:

  • Maintain populations in Green River subbasin and EITHER in upper Colorado River subbasin or in San Juan River, each > 5,800 adults
  • Maintain genetic* refuge of adults in Lake Mohave
  • Maintain two populations in lower basin, each > 5,800 adults [5]

Links

Documents

Reports and Publications

2018

2017

2015

2014

2012

2009

LTEMP BiOp Conservation Measures for Razorback Sucker [6] (2016)

Ongoing actions:

Reclamation would continue to assist the NPS, FWS, and the GCDAMP in funding larval and small-bodied fish monitoring in order to:

  • Determine the extent of hybridization in flannelmouth and razorback sucker collected in the western Grand Canyon.
  • Determine habitat use and distribution of different life stages of razorback sucker to assist in future management of flows that may help conserve the species. Sensitive habitats to flow fluctuations could be identified and prioritized for monitoring.
  • Assess the effects of TMFs and other dam operations on razorback sucker.

Other Stuff
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