Abstract

Effective management and conservation of riverine fish species relies on identification of habitats that contribute recruits to fish populations. Paddlefish are an important commercial and recreational species inhabiting North American large rivers. However, despite knowledge of adult paddlefish movement patterns in large rivers, their principal natal environments and early life dispersal patterns remain unknown. Paddlefish dentary microchemistry can be used to identify natal environment of fish in large river networks such as the middle Mississippi River (MMR) and tributaries. The goals of this study were to (1) use dentary microchemistry (strontium:calcium ratios; Sr:Ca) to determine natal environment and potential drift for age-0 paddlefish collected from the MMR, and (2) assess whether MMR river reach or year of collection influenced the percentage of recruits originating from different rivers. Age-0 paddlefish were collected during 2010-2011 from two reaches of the MMR (upstream and downstream of the Kaskaskia River confluence). Water samples from the MMR and tributaries (upper Mississippi, Missouri, Illinois, Osage, and Kaskaskia rivers) were collected during 2006-2016. Water Sr:Ca differed among rivers, enabling identification of natal environment for individual fish using dentary core Sr:Ca. The MMR (44-69% of fish sampled) and Missouri River (25-45% of fish sampled) were the primary natal environments for age-0 paddlefish across both river reaches and collection years. The upper Mississippi River and smaller tributaries contributed few recruits (

Journal Title

River Research and Applications

Volume

35

Issue

9

Page Numbers

1554-1562

DOI

10.1002/rra.3526

Available for download on Sunday, August 15, 2021

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Link to publisher version

http://dx.doi.org/10.1002/rra.3526