Habitat Suitability Criteria for Virile (Northern) Crayfish
August 2011 to May 2014
A concern with the survival and persistence of native species is the introduction of non-native species. In the Southwest, especially in Arizona, a growing concern is the introduction of the non-native northern crayfish Orconectes virilis. Northern crayfish not only negatively affect native threatened and endangered fish populations but also other vertebrates (Sonoran mud turtles Kinosternon sonoriense, leopard frogs, Rana chiricahuensis, and narrow-headed garter snake Thamnophi rufipunctatus), macroinvertebrates, and aquatic plants. Effective or efficient control methodologies for crayfish have proven elusive; however, reducing the amount of habitat for crayfish might give promise. Thus, determining which habitat parameters are optimal for crayfish and more importantly, which parameters are unsuitable for crayfish is critical. This study is designed to develop habitat suitability criteria for northern crayfish then identify and assess overlap in habitat criteria for other managed aquatic species (Apache trout, Oncorhynchus giliae apache, brown trout Salmo trutta, or rainbow trout, O. mykiss) that may lead to successful management of these species. We sampled crayfish in the West Fork of the Black River every 5 meters moving upstream using a quadrat sampler. This enabled us to determine occupied and unoccupied locations and measure habitat parameters of each location. These data are being analyzed to determine quantitative habitat parameters or habitat suitability criteria for northern crayfish. We also plan to gather data from other streams to make this study more robust.