Behavior and Reproductive Ecology of the Sicklefin Redhorse: An Imperiled Southern Appalachian Mountain Fish

Abstract

Many nongame fishes are poorly understood but are essential to maintaining healthy aquatic ecosystems globally. The undescribed Sicklefin Redhorse Moxostoma sp. is a rare, imperiled, nongame fish endemic to two southern Appalachian Mountain river basins. Little is known of its behavior and ecology, but this information is urgently needed for conservation planning. We assessed the spatial and temporal bounds of spawning migration, quantified seasonal weekly movement patterns, and characterized seasonal and spawning behavior using radiotelemetry and weir sampling in the Hiwassee River basin, North Carolina–Georgia, during 2006 and 2007. Hiwassee River tributaries were occupied predominantly during the fish's spawning season, lower reaches of the tributaries and the Hiwassee River were primarily occupied during the postspawning season (i.e., summer and fall), and lower lotic reaches of Hiwassee River (upstream from Hiwassee Lake) were occupied during winter. Adults occupied Hiwassee Lake only as a movement corridor during spawning migrations. Both sexes conducted upstream spawning migrations simultaneously, but males occupied spawning tributaries longer than females. Sicklefin Redhorse exhibited interannual spawning‐area and tributary fidelity. Cold water temperatures associated with hypolimnetic releases from reservoirs and meteorological conditions influenced spawning migration distance and timing. During 2007, decreased discharges during the spawning season were associated with decreases in migration distance and spawning tributary occupancy duration. Foraging was the dominant behavior observed annually, followed by reproductive behaviors (courting and spawning) during the spawning season. No agonistic reproductive behavior was observed, but females exhibited a repetitious postspawning digging behavior that may be unique in the family Catostomidae. Our findings suggest that protection and restoration of river continuity, natural flow regimes, seasonally appropriate water temperatures, and geographic range expansion are critical components to include in Sicklefin Redhorse conservation planning. Fisheries and ecosystem managers can use our findings to justify sensitive management decisions that conserve and restore critical streams and rivers occupied by this imperiled species.

Migratory redhorse suckers provide subsidies of nitrogen but not phosphorus to a spawning stream

“…First, our distribution of egg inputs based on the relative daily abundance of redhorses over the course of the migration might not reflect reality. Considering the sequential nature of redhorse migrations (Favrot, 2009; Kay et al., 1994), one might expect spawning activity to occur in pulses associated with the abiotic spawning preferences (i.e. temperature, discharge, photoperiod, etc.)…”

“…shorter residence time = larger population size), which is challenging to estimate. Favrot (2009) found that the female residence time of sicklefin redhorse averaged 35 days in Hiwassee River tributaries—including several individuals in Brasstown Creek. However, this estimate appeared to be exaggerated by several females spending 80–300 days in their spawning streams.…”

Capture–translocation restores spawning migration connectivity of Razorback Suckers in the fragmented San Juan River

“…Many riverine species rely on migrations between habitats and geographic areas where critical resources exist to complete components of their life cycle, such as reproduction and recruitment (Cooke et al 2011;Hicks et al 2020). Movement barriers cause declines in fish populations by impeding dispersal and reducing gene flow among populations (Gido et al 2016;Favrot and Kwak 2018). Where barrier removal is difficult or undesirable due to human infrastructure needs, bypass channels and active fish transportation above barriers are common methods to restore connectivity (Ovidio and Philippart 2002;Lusardi and Moyle 2017).…”

State-space models to describe survival of an endemic species in the Little Tennessee River basin

“…Maturation occurs between 5 and 8 years (Jenkins, 1999;Jenkins, 2005). Adults live in rivers and large creeks year-round with migrations during spawning where females exhibit significant spawning site fidelity (Favrot, 2009;Favrot and Kwak, 2018). There is some evidence that males and females exhibit different movement patterns (Stowe, 2014).…”