Sicklefin Redhorse Reproductive and Habitat Ecology in the Upper Hiwassee River Basin of the Southern Appalachian Mountains

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Title: Sicklefin Redhorse Reproductive and Habitat Ecology in the Upper Hiwassee River Basin of the Southern Appalachian Mountains
Author: Favrot, Scott Douglas
Advisors: Dr. Thomas J. Kwak, Committee Chair
Dr. Wayne C. Starnes, Committee Member
Dr. Kenneth H. Pollock, Committee Member
Abstract: Hiwassee River tributaries were frequently occupied by adult sicklefin redhorse Moxostoma sp. during the spawning season; lower reaches of tributaries and Hiwassee River were primarily occupied during the postspawning season; and lower reaches of Hiwassee River were most heavily used during winter. Sicklefin redhorse selected annual, seasonal, and spawning microhabitat non-randomly. Sicklefin redhorse generally were associated with swift thalweg currents, shallow depths, and coarse substrates (e.g., boulder and bedrock) supporting river weed Podostemum ceratophyllum. However, different microhabitats were selected seasonally and during spawning. During 2007, mean daily water temperature for observed sicklefin redhorse spawning was 17.5 °C (11.0–21.1 °C). Male and female sicklefin redhorse conducted spawning migrations simultaneously; however, males tended to occupy spawning tributaries longer than females. All sicklefin redhorse that conducted spawning migrations in both 2006 and 2007 demonstrated spawning tributary fidelity. Foraging was the most common behavior observed for adult sicklefin redhorse with bedrock being the dominant foraging substrate annually. Sicklefin redhorse reproductive behavior was atypical for the genus Moxostoma. An undescribed repetitious post-spawning digging behavior was observed for spawning females. Spawning substrate samples reveal that very coarse gravel and small cobble were dominant spawning substrates. My results increase knowledge pertaining to reproductive ecology, seasonal behavior, and suggest critical management issues important to the life history of the sicklefin redhorse. The spawning migration of black redhorse Moxostoma duquesnei, golden redhorse Moxostoma erythrurum, river redhorse Moxostoma carinatum, sicklefin redhorse and silver redhorse Moxostoma anisurum was sampled with resistance board weirs and prepositioned areal electrofishers (PAEs) during the spring of 2006 and 2007 in Valley River, North Carolina. Spawning was observed for all five redhorse species in 2007 at water temperatures generally ranging from 8–21 °C and mean daily Valley River flows ranging from 1.7–4.5 m3/s. Silver redhorse migrated and spawned first followed by black redhorse, sicklefin redhorse, golden redhorse, and river redhorse with considerable overlap occurring. Male golden redhorse and river redhorse displayed agonistic behavior and spawning site fidelity, while female sicklefin redhorse displayed site fidelity. Silver redhorse and river redhorse were not significantly different (P > 0.05) in size (i.e., total length and weight), while the other redhorse species exhibited a morphological interspecific significant difference (P < 0.05). The spawning migration chronology between males and females was significantly different (P < 0.05) for black redhorse and sicklefin redhorse and not significantly different (P > 0.05) for the other three species; however, spawning migration bounds for both sexes of all five species were similar. All five species typically selected spawning microhabitat non-randomly. Interspecific redhorse spawning site microhabitats were generally significantly different (P < 0.05) due to deviation of one or two species. My findings suggest that seasonal, habitat, and ethological reproductive isolating are functioning within Hiwassee Basin; however, indicate that anthropogenic activities and alterations have the ability to diminish or remove these reproductive barriers. I compared resistance board weirs and prepositioned areal electrofishers to determine gear efficiency for migrating potamodromous fishes. Fish species richness and diversity were higher for PAE total catch, while weir catch had higher species dominance. Total PAE catch by number was much higher than total weir catch; however, PAE total biomass was lower than weir total biomass. Weirs generally did not demonstrate a velocity bias, while PAEs did. On average, PAE mortality was five times higher than weir mortality. My results will assist fisheries managers in selecting the most appropriate gear to address research and management objectives when sampling medium-sized rivers.
Date: 2009-04-23
Degree: MS
Discipline: Fisheries and Wildlife Sciences

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