Date of Award
Master of Science
Understanding spatial patterns in population demographics and the principal natal environments supporting riverine fish populations are important for fisheries management. Although the black basses are among the most popular groups of game fishes in North America, relatively little information exists regarding demographics and environmental history of spotted bass Micropterus punctulatus in riverine environments. Fin ray microchemistry was used to identify natal environment and age estimates from sectioned fin rays used to estimate growth and mortality rates for spotted bass in Smithland pool of the Ohio River and three tributaries. Spotted bass were collected from 2014-2016 in headwater reaches of tributaries using electrofishing, angling, and a seine net, while electrofishing was used exclusively in the Ohio River and lower tributary reaches. Spotted bass in the Ohio River generally lived longer and grew larger than conspecifics in tributaries, although mortality rates were not definitively different. Differences in water Sr:Ca and Ba:Ca among the Ohio River and tributaries were reflected in fin rays from age-0 and age-1 fish. Eighteen percent of spotted bass ≥ age-2 captured in the Ohio River originated in tributaries, whereas 15% captured in tributaries originated in the Ohio River. Although most fish remained in their natal environment, small tributaries can be a supplemental recruitment source for spotted bass populations and fisheries in large rivers. This study highlights the utility of fin rays for microchemical analysis and age estimation of spotted bass.
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