Techniques for Sampling Larval and Juvenile Fishes in Appalachian Mountain Rivers

Little effort has been directed toward sampling larval and juvenile fishes in Appalachian Mountain rivers, despite the relevance to fish population and assemblage dynamics.  We compared the efficiency of four techniques for sampling larval and juvenile fishes from sites located along the Valley River, a major tributary to the Hiwassee River in Western North Carolina.  A diverse fish assemblage composed of 51 species representing 10 families, including six species of redhorse (genus Moxostoma), inhabit the Valley River and occupy it for spawning.  Light trapping and drift netting were most effective for sampling larvae 5 – 20 mm total length (TL), and highest catch rates (of all species) occurred in early- to mid-June.  Visual dip netting was most effective for larvae 10 – 25 mm TL with highest efficiency in early-June.  Backpack electrofishing was most effective for sampling juvenile fish that were not vulnerable to drift nets or light traps and had achieved swimming ability to evade capture with a dip net.  These findings may guide fisheries scientists in planning seasonal sampling to most effectively characterize the early life stages of fishes in freshwater mountain rivers.