1. Aquatic Parasitology Laboratory, School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, Auburn, Alabama 36849.
2. Centro de Estudios Parasitológicos y de Vectores, (CONICET-UNLP), La Plata, 1900, Argentina.
3. Division of Coastal Sciences, The University of Southern Mississippi, Ocean Springs, Mississippi 39564.