1. Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas 77843, USA
2. Department of Natural Resource Management, Sul Ross State University, Alpine, Texas 78930, USA
3. Department of Pathobiology, Texas A&M University, College Station, Texas 77843, USA
4. TerraMar Environmental Research Ltd., 8617 Lochside Drive, Sidney, British Columbia V8L 1M8, Canada