Age, growth, home range, movement, and habitat selection of redeye bass (Micropterus coosae) from the middle Tallapoosa River tributaries (Alabama, USA).

Abstract

Redeye bass Micropterus coosae is a common, but underutilized sport fish resource in Alabama. This species is the most attractive of all the black basses, and has a reputation as a formidable catch on light tackle. Redeye bass are typically abundant in rivers and streams only navigable by canoes or kayaks. The purpose of this study was to determine age and growth, movement, home range, and habitat selection of redeye bass from the middle Tallapoosa Watershed, in Alabama. Age and growth was determined using validated hard structures (otoliths). Additionally, alternative non-lethal structures (spines) were also investigated. Results indicated there were minimal differences in age assignment between structures when data were combined; however variation was observed when individual age classes were examined. Spine aging tended to underestimate actual age, but this structure may be useful to gain a general understanding of age class structure if euthanasia is not desired. Differences in age and growth between tributary and mainstream resident redeye bass were not observed. Movement, home range, and habitat selection were determined using radio telemetry methods. Proper tagging procedures were determined prior to initiation of this study. Redeye bass generally showed some evidence of site fidelity during hydrologically stable periods, but did not show fidelity during high flow periods. Movement rates were more variable for smaller redeye bass, while larger fish moved less. On average redeye bass moved 705 m during the ten weeks they were monitored. Home range estimates were difficult to determine due to limited battery life of transmitters. Fifty percent (core) kernel density estimates were similar to what was reported for other black bass species. Ninety-five percent kernel density estimates were calculated, but this research lacked sufficient samples sizes to conclude any valid biological inferences. Future research should focus on tagging larger fish that can be tagged with larger transmitters to gain a better understanding of home range for the species. Habitat research indicated that there appeared to be some intra-specific competition between redeye bass. Tagged fish were never associated with one another, and juvenile fish appear to occupy sub-optimal habitats. Results from habitat selection analysis indicated that the presence of canopy cover and interactions between specific variables were important predictor variables of redeye bass selection. Some differences were observed between adult and juvenile habitat selection. Adult fish selected locations with an interaction between interactions between relative depth and presence of instream features, interactions between boulders and canopy cover, and presence of instream features reduced distances to shore interactions. Juvenile fish also selected areas with increasing canopy cover, increasing relative depth, interactions between the presence of instream features and depth, and a complex interaction between boulder and sand substratum, that had increased depths. Results from this research will assist managers with gaining a greater understanding of life history requirements of redeye bass, and facilitate management of this potentially valuable fisheries resource.