Experimental infection of the endangered bonytail chub (Gila elegans) with the Asian fish tapeworm (Bothriocephalus acheilognathi): impacts on survival, growth, and condition

Hansen, S. P.; Choudhury, A.; Heisey, D. M.; Ahumada, J. A.; Hoffnagle, T. L.; Cole, R. A.

Abstract:

Bothriocephalus acheilognathi Yamaguti, 1934, a tapeworm known to be pathogenic to some fish species, has become established in the endangered humpback chub (Gila cypha Miller, 1964) in Grand Canyon, USA, following the tapeworm‘s introduction into the Colorado River system. The potential impact of this tapeworm on humpback chub was studied by exposing the closely related bonytail chub (Gila elegans Baird and Girard, 1853) to the parasite under a range of conditions that included potential stressors of humpback chub in their natal waters, such as abrupt temperature change and a limited food base. Survival of infected fish under low food rations was considerably lower than that of control fish, and mortality of infected fish began 20days earlier. Growth of infected fish was significantly reduced, and negative changes in health condition indices were found. No significant negative impacts were revealed from the synergistic effects between temperature shock and infection. Bothriocephalus acheilognathi does present a potential threat to humpback chub in Grand Canyon and should be considered, along with conventional concerns involving altered flow regimes and predation, when management decisions are made concerning conservation of this endangered species.// Bothriocephalus acheilognathi Yamaguti, 1934, un ver plat connu comme pathog??ne pour certaines esp??ces de poissons, s‘est associ?? au A (Gila cypha Miller, 1964), une esp??ce menac??e du Grand Canyon, ??.-U., apr??s l‘introduction du ver dans le r??seau hydrographique du Colorado. Nous avons ??tudi?? l‘impact potentiel de ce ver plat sur le m??n?? bossu en exposant l‘esp??ce proche Gila elegans Baird et Girard, 1853 au parasite sous une gamme de conditions qui incluent les facteurs potentiels de stress des m??n??s bossus dans leurs cours d‘eau d‘origine, tels que les changements abrupts de temp??rature et des ressources alimentaires limit??es. La survie des poissons infect??s dans des conditions de nourriture limit??e est substantiellement r??duite par comparaison aux poissons t??moins et la mortalit?? des poissons infect??s d??bute 20 jours plus t?‘t. La croissance des poissons infect??s est significativement r??duite et il y a des changements n??gatifs dans les indicateurs des conditions de sant??. Il n‘y a pas d‘impact n??gatif significatif apparent des effets de synergie du choc thermique et de l‘infection. Bothriocephalus acheilognathi est donc une menace potentielle pour le m??n?? bossu dans le Grand Canyon et il devra ??tre pris en consid??ration, au m??me titre que les pr??occupations habituelles au sujet de la modification du r??gime des eaux et de la pr??dation, lorsque des d??cisions seront prises au sujet de la conservation de cette esp??ce menac??e.

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Article

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1003999

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Hansen, S. P.; Choudhury, A.; Heisey, D. M.; Ahumada, J. A.; Hoffnagle, T. L.; Cole, R. A.

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National Wildlife Health Center

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1394

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English

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Canadian Journal of Zoology

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p. 1383-1394

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Experimental infection of the endangered bonytail chub (Gila elegans) with the Asian fish tapeworm (Bothriocephalus acheilognathi): impacts on survival, growth, and condition; 2006; Article; Journal; Canadian Journal of Zoology; Hansen, S. P.; Choudhury, A.; Heisey, D. M.; Ahumada, J. A.; Hoffnagle, T. L.; Cole, R. A.