Monday, June 4, 2007 - 1:00 PM
35

Invasive Crayfishes of the New/Kanawha River System in West Virginia and a Comparison of Large River Collection Techniques

Tom Jones, Casey Swecker, Brad Musser, Geoffrey D. Smith, and Keith G. Donahue II. Dept. of Integrated Science and Technology (IST), Marshall University, Huntington, WV 25755

Of the 6 orconectid crayfishes presently found in West Virginia, 2 are invasive species: Orconectes rusticus and Orconectes virilis. Historically, researchers located only isolated populations of O. rusticus and O. virilis in tributaries of the Ohio and Kanawha Rivers and from the eastern panhandle and New/Kanawha River, respectively.  Recent collections, however, have indicated a much broader distribution of both species than was first thought.  Collections were made by hand (including SCUBA assisted), seining, trapping, and backpack electrofishing as there are no consensus means for collecting crayfishes from large rivers.  A floating turbidity fence was utilized to assess different capture efficacies in large rivers.  We compared efficiency of methods in a series of 100 ft. random bank-side habitats.  Multiple passes were made using each technique to calculate population size by a removal method.  Population sizes varied from zero to 157 individuals.  Hand capture consistently ranked the most efficient method of collection.  A higher percentage of reproductive males were collected by hand capture, probably the result of cover object selection by the collector.  Significant range expansion of these two invasive species in the New/Kanawha system, Ohio River and other streams in West Virginia warrant greater attention by regulatory agencies and researchers.

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