Avian Piscivoress Vector in the Greater Yellowstone Ecosystem

Authors

  • Todd M. Koel Center for Resources, Fisheries and Aquatic Sciences Program, P.O. Box 168, Yellowstone National Park, Wyoming 82190
  • Billie L. Kerans Department of Ecology, Montana State University, P.O. Box 173460, Bozeman, Montana 59717
  • Scott C. Barras USDA/APHIS/WS National Wildlife Research Ceneter, Mississippi Field Station, P.O. Box 6099, Mississippi State, Mississippi 39762
  • Katie C. Hanson USDA/APHIS/WS National Wildlife Research Ceneter, Mississippi Field Station, P.O. Box 6099, Mississippi State, Mississippi 39762
  • John S. Wood Pisces Molecular LLC, 2200 Central Avenue, Suite F, Boulder, Colorado 80301

Abstract

Although often blamed on movement of trout, the dispersal vector of Myxobolus cerebra/is among aquatic habitats often remains unknown. Occurrence of whirling disease in native Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) within the highly protected environment of Yellowstone Lake is one example. Given their local abundances, we sought to clarify the potential role of highly mobile piscivorous birds in the dissemination of M cerebra/is to otherwise isolated habitats. Six each of American White Pelicans (Pelicanus erythrorhynchos), Double-crested Cormorants (Phalacrocorax auritus), and Great Blue Herons (Ardea herodius) were held in an aviary and fed known-infected or uninfected rainbow trout (O. c. mykiss). Fecal material produced during IO-day periods before and after feeding was collected to determine if M. cerebralis could be detected and, if so, remained viable after passage through the gastrointestinal tract of these birds. Fecal samples from all (100%) of the nine birds fed known-infected trout and collected during days 1-4 following feeding tested positive for the presence of M. cerebra/is by PCR. In addition, Tubifex tubifex fed fecal material from known-infected herons produced triactinomyxons in laboratory cultures, confirming the persistent viability of the parasite. Given the infection prevalence of cutthroat trout within Yellowstone Lake, pelicans, cormorants, and herons can move an estimated 1.27 billion M cerebralis myxospores in the ecosystem during a I 00-day breeding season each year. Piscivorous birds have the potential to concentrate and release M cerebra/is myxospores with fecal material into habitats highly suitable for T. tubifex, forming the basis of a positive feedback loop where the proliferation of M cerebra/is is supported.

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Published

2009-12-31

Issue

Vol. 15 No. 4 December (2009)

Section

Individualized Meeting Abstracts