Spatial and Temporal Variation of Black Bass Population Dynamics in the Upper Ohio River: Insights from Ten Years of Standardized Sampling

Black bass, including largemouth bass Micropterus salmoides, spotted bass Micropterus punctulatus, and smallmouth bass Micropterus dolomieu, are highly pursued sportfish in the upper Ohio River.  To effectively manage these fisheries, we sought to understand the spatial and temporal variation in abundance, reproductive success, growth, and mortality, and the mechanisms affecting this variation among the 10 navigational pools in the 724 km section of the upper Ohio River bordering Ohio.  Annual black bass population assessments were conducted in the month of September from 2005-2015 using shoreline electrofishing.  Largemouth bass were most abundant in the lower pools, whereas smallmouth bass were more abundant in the upper pools.  Spotted bass were ubiquitous across pools but catches were generally low.  Growth rates were variable and did not exhibit consistent spatial or temporal trends.  Reproductive success, indexed by age-0 catch-per-effort, was highly variable across pools and years.  The physical, hydrological, chemical, and biological characteristics of the Ohio River vary substantially over time and across the study reach.  Future research will explore abiotic and biotic factors that drive spatial and temporal variation in black bass population characteristics. Identifying these linkages may help inform the management of these species in the Ohio River.