Phenology, Growth, and Early Life History of Six Sympatric Suckers

Suckers (family Catostomidae), and especially redhorse (genus Moxostoma), comprise a taxon that is of high conservation concern but has received relatively little attention from the scientific community.  Valley River, a major tributary to the Hiwassee River in Western North Carolina, is inhabited by seven species of suckers, including the Sicklefin Redhorse, an imperiled endemic species.  Larval and juvenile suckers were sampled from Valley River during April – September of 2013 and 2014, and were identified to species using genetic barcoding (N=856).  Fish were measured and development was indexed based on yolk-sac absorption and fin formation.  Six species in various stages of development were collected (13.9 – 156.0 mm TL).  Silver Redhorse larvae emerged in early-May, Northern Hog Sucker during early-May through early-June, Black Redhorse in late-May, Golden Redhorse and Sicklefin Redhorse in early-June, and River Redhorse in late-June; this pattern parallels their known spawning sequence.  Growth rates differed among species (P<0.05), and Northern Hog Sucker and Black Redhorse developed at smaller sizes than the other species (P=0.0014).  A basic understanding of the early life histories of sympatric suckers is essential for identifying factors that may differentially affect recruitment and for planning appropriate ecosystem and fish conservation and management measures.