Ontogenetic habitat shifts and habitat use in an endangered minnow, Notropis mekistocholas

Abstract

Henderson AR, Johnston CE. Ontogenetic habitat shifts and habitat use in an endangered minnow, Notropis mekistocholas. Ecology of Freshwater Fish 2010: 19: 87–95. © 2009 John Wiley & Sons A/SAbstract – Information on larval and juvenile habitat use is virtually absent for fishes. Our objective was to document habitat use of larval and juvenile Cape Fear shiners Notropis mekistocholas, an endangered species, in both natural and lab settings so that a better understanding of habitat requirements in all life stages can be achieved. We measured habitat parameters of areas used by all life stages of N. mekistocholas in the summers of 2007–2008 in the Rocky River, North Carolina. Field data suggests larvae use more shallow depths (mean = 31.6 cm) and reduced water velocities (mean = 0.02 m·s−1) than adults (mean = 56.3 cm, 0.10 m·s−1), and juveniles 15–25 mm often school with adults. Results of lab studies support field observations. In the mesolarval and metalarval stages N. mekistocholas were selective in their use of water velocity (P = 0.013) and depth (P = 0.001). In multiple juvenile stages, N. mekistocholas were selective for water velocity (P = 0.015), and depth (P < 0.001), choosing deeper depths and higher water velocities than larvae. These results demonstrate ontogenetic shifts in habitat use of N. mekistocholas and suggest that water velocity and depth are critical to successful recruitment for this species.