Monday, May 26, 2008 - 11:15 AM
48

Investigating competition among lineages of t. tubifex and the potential for biological control of whirling disease

Christine M. Clapp1, Dana Winkelman1, and Kevin Thompson2. (1) Department of Fish, Wildlife and Conservation Biology, Colorado State University, 201 JVK Wagar, Fort Collins, CO 80523, (2) Colorado Division of Wildlife, 2300 S. Townsend Ave., Montrose, CO 81401

Whirling disease research in recent years has focused on selective breeding of Myxobolus cerebralis resistant trout, but not all management situations are conducive to the use of resistant trout.  Less attention has focused on resistance in the oligochaete host, Tubifex tubifex, but not all T.  tubifex lineages are susceptible to infection and some actually ingest and inactivate spores of M. cerebralis.  We are investigating resistant T. tubifex as a potential biological control of the parasite.  Laboratory experiments and a field manipulation were used to assess the competitive ability of resistant lineage V T. tubifex against susceptible lineage III.  Replacement series laboratory experiments consisted of 2-3 densities and 3-5 proportions of each lineage, both exposed and unexposed to M. cerebralis.  Exposed lineage III worms tested 100 percent positive for M. cerebralis prior to assigning treatments.  Myxobolus cerebralis exposure increased the competitive advantage of resistant lineage V worms over susceptible lineage III.  We also introduced lineage V worms to Spring Creek, Gunnison County, Colorado.  Post-introduction monitoring has been ongoing for two years to track establishment and movement of lineage V worms.  Post-introduction, lineage V worms have been found at all four introduction sites and movement has been detected downstream at one site.  


Web Page: whirling disease, competition, T. tubifex

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