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ABSTRACTS OF PRESENTATIONS IN ORDER PRESENTED
<br />incrementado su rango la sur del Valle Ruby y posiblemente se hibridiza con Relictos, el Lago Franklin otra vez estuvo
<br />seco este ano.
<br />12. Charal Tui del Valle del I-ago Fish, Gila bicolor ssp. - Solo la poblacion del Rancho McNet se encuentra
<br />saludable, pero la carpa dorada ha sido introducida a este sistema. El Lago Fish estaba casi seco, sin embargo un solo
<br />juvenil se atrapd con red de cuchara en un area somera antes de que se secara totalmente. No se encontro pez alguno
<br />en el area de los manantiales Pothole. Se ban hecho tambien planes por el poblado de Dyer para construir un gran Parque
<br />con posas de pesca. Esta construccion ya se inicid y desafortunadamente es solo un cuarto de milla del Rancho McNet.
<br />La Compaiifa Lake Fish Power tiene planes para posos geotermales justo al norte de esta area. Se requiere mds trabajo
<br />sobre la distribucion en este Valle.
<br />13. Charal de espina del Valle Oasis, Rhinichthys osculus spp. - Las condiciones de sequfa han restringido a la
<br />poblacidn de este pez a cinco pequenas areas dentro del Valle Amargosa. La poblaciones mas fuertes estan dentro de los
<br />lunites de la ciudad de Beatty, y de un sistema de manantiales localizado en La Fleur en la porci6n norte del Valle.
<br />Ambas areas tienen aproximadamente 100 m de largo, y esUm algo degradadas.
<br />14. Charal moteado del Valle Big Smoky/Valle Monitor y Charal tui del Valle Big Smoky, Rhinichthys osculus ssp.,
<br />Gila bicolor spp. - En 1992, las poblaciones parecen estar estables en todas las areas que fueron estudiadas previamente
<br />en 1978. Con el permiso de los dueiios de las tierras, los esfuerzos adicionales de recuperacion deben intentar expandir
<br />las poblaciones en el Valle Smoky a los habitat historicos.
<br />15. Charal de espina del Valle Pahranagat, Rhinichthys osculus spp. - Se encontro una posible forma no descrita
<br />del charal moteado en la parte baja del Valle Pahranagat en 1987. Estos peces fueron movidos del manantial L y
<br />manantial North Cottonwood y fueron colocados en el manantial Maynard, un manantial libre de exoticos. Despues de
<br />la transferencia en 1991, se llevd a cabo la reproduccidn, pero en 1992 no se observaron juveniles del ano. Cuando haya
<br />un numero suficiente de ejemplares para colecci6n, debe de llevarse a cabo el trabajo de sistemdtica para estos peces.
<br />16. Pez de manantial del Rio Moorman White, Crenichthys baileyi thermophilus - Este sistema de manantiales
<br />terinales ban sido invadidos por la lobina del reservorio de abajo, y el mimero de peces es extremadamente bajo. Estas
<br />lobinas deben ser sacadas, se deben implementar barreras de tal manera que estas poblaciones se protejan.
<br />17. Miscelanea de especies de peces. Algo de tiempo al azar se dedic6 a las siguientes especies o localidades: charal
<br />tui del Valle Hot Creek, charal de espina del Valle Independencia, charal tui del valle Ferrocarril, matalote del Canon
<br />Wall, Arroyo del Valle Meadow, Rfo Muddy (Moapa), Valle del Lago del Pez Pequeiio, y Valle del Rfo Blanco.
<br />BURL, T. (Bureau of Reclamation, Lower Colorado Region, Boulder City, Nevada)
<br />Agency report: Bureau of Reclamation, Lower Colorado Region / Reporte de agencia:
<br />Oficina de Reclamaci6n, Region del Bajo Colorado
<br />KEYWORDS: razorback sucker; Lake Mohave; Lake Mead; canal system; bonytail chub; Virgin River; Gila River;
<br />Devil's Hole pupfish; Lake Havasu
<br />ABSTRACT
<br />This report covers both the Lower Colorado Region and the Denver Engineering and Research Center activities.
<br />Activities of the Upper Colorado Region, including Glen Canyon Environmental Studies, are covered in a separate
<br />agency report.
<br />Lower Colorado Region activities focused on razorback sucker (Xyrauchen texanus) this year, mainly with rearing
<br />fish in isolated backwaters of Lake Mohave. On Lake Mohave adult fish were placed in Yuma Cove where they
<br />successfully spawned and produced larvae. The young were monitored from February through October, showing excellent
<br />growth. A barrier net was installed at Davis Cove near Davis Dam, predator fishes were partially removed and 10,000
<br />fingerlings (average TL 68 mm) were transferred to the backwater from Dexter National Fish Hatchery in mid-June.
<br />These fish also were monitored through October and again excellent growth was noted. Considerable information was
<br />gleaned through observation of these fishes and their occupied habitats. More detailed information is presented elsewhere
<br />in the program by Gordon Mueller. Related to this, some 6000 bonytail chub (Gila elegans) were transferred from Dexter
<br />National Fish Hatchery on October 5, 1992, to the backwater at Davis Cove. These fish will be monitored through the
<br />next year along with the razorback suckers.
<br />A helicopter survey on Lake Mead during March identified numerous aggregations of fishes, some thought to be
<br />adult razorback suckers. Follow-up netting and electro- shocking by Nevada Division of Wildlife and Reclamation
<br />biologists yielded 30 adult razorback suckers from Lake Mead. Gametes were collected for MtDNA analyses and
<br />forwarded to Arizona State University. Fish were processed, PIT tagged, and released. This is the largest collection of
<br />these fish from Lake Mead in over 20 years.
<br />On the lower portions of the Colorado River, Reclamation participated in collections of razorback suckers from
<br />the Colorado River Indian Tribes (CRIT) canal system near Parker, AZ. Reclamation is working with the CRIT biologists
<br />to develop native fish- rearing areas on tribal lands along the river, and we expect to begin construction this summer on
<br />the first one at No-Name Lake at the southern end of the Reservation.
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