IBoCEEDD{GS oFTIfi DESERT Flsics CorrNcIL, 1995 sYr“foSITIM Vorrrlv€)On& - RlErsrs 1996

Authors: culturales del 5rea, 4) integraci6n de todas las actividades de maneio de recursos en el irea, 5) prevenci6n

Year: 1995 (xxvii)

Abstract

The Asian tapeworrn, Bo*nocephalus arheilognathi, was introduced into the United States via imported grass ca{P in the early 1970’s. It has since become well established in t}re southeast and mid-south “t d hrt been recently found in the southwest. The definitive host in the life qycie of B. acheilognathi is grprinid fishes and therefore, is a potential threat to the federally endangered humpback chub,-Grln grpha’,in the Colorado River, Grand Canyon. In past studies, Arizona Game and Fish Department has found that humpbadc chub in the little Colorado River (LCR) were infested with the Asian i”p“*o.rrr. However, the coldwater of the mainstem Colorado River may be limiting their expansion beyond the LCR This study was conducted to determine the prevalence of. B, a&eilqnathi in two cyprinid firh“r, fathead minnows, Pimephala pramelas, and speckled dace, Rhinichilrys osculw, and determine if it has expanded its distribution to sites outside of the ICR Preliminary data from 1994 show that 54% of the humpback c1.ttb, 2T% of the speckled dace, and 696 of the fathead minnows that were caught were infestea witf, the Asian tapeworm. All infested humpb_adc chub were caught in a l5-mile stretch o1 th. Colorado River iust downstre^am from the mouth of the LC& the likely source of their infestation. RESTI?I{EN ElAsian tapewomr” Bokrimephahs a&eilognathi. fue introducido en Estados Unidos via importaci6n de grass carP a principio de los l97o’s. Desde entonces se estableci6 en el sureste y parte central sur yrecientemente se encontr6 en el Suroeste. El hospedero definitivo en el ciclo de vida de-&. arheilognathi sinlos peces ferini{1f for ello, es una arnenaza potencial para el charalito iorobado, Gth cypha cJnsiderad.aamlazada por la federaci6n en el Colorado River, Grand Canyon. En estudios anteriorei Arizona Gameand Esh Department encontr6 que el charalito jorobado en el Little Colorado River (LCR) estaba infestadocon el Asian taPeworm- Sin embargo, el agua fria de la corriente principal del Colorado River puede estarlimitando su e4pansi6n a trav6s del LCd Este estudio se efectu6 para determinar la prevalincia de B.arheilagnathi en dos especies de ciprinidos, los fathead minnows, Pimephal“es promelas,y el speckled dace,RhitrichthYs osculus, y determinar si ha e4pandido su distribuci6n a sitios fuera del LCR Los datospreliminares de 1994, muestran que el S+S6 de los charalito iorobado, 27% delos speckled dace, y el 6%de los fathead minnows, capturados estaban infestados con el Asian tapeworm. Todos los charalito iorobado infestados fueron capturados en un tramo de 15 millas del Colorado River aguas abajo de la bocadel LC& la que parece ser la fuente de su infestaci6n. 25