Otolith microchemistry reveals natal origins of walleyes in Missouri River reservoirs
January 2, 2016 - Andrew K. Carlson, Mark J. Fincel, Brian D. S. Graeb
Journal or Book Title: North American Journal of Fisheries Management
Volume/Issue: 36
Year Published: 2016
Reproductive habitats are vital for sustaining fish populations, but their location and relative natal contributions are often unknown or poorly understood. We used otolith microchemistry to examine natal origins of Walleyes Sander vitreus in Missouri River reservoirs (i.e., Oahe, Sharpe, Francis Case, and Lewis & Clark), North Dakota and South Dakota. Water Sr:Ca and Ba:Ca were spatially heterogeneous and temporally consistent in all impoundments. Age-0 otolith Sr:Ca and Ba:Ca permitted reclassification to known natal habitats (i.e., tributary, embayment, mainstem) and individual sites with 87 and 75% accuracy, respectively. Natal contributions were highest in tributaries, particularly those in Lake Oahe, where 32% of all adults and 77% of Lake Oahe adults hatched. Embayments and mainstem environments had high natal contributions (i.e., 67–78%) in lakes Sharpe, Francis Case, and Lewis & Clark, where tributaries are less abundant. Our research demonstrates the utility of otolith microchemistry for measuring habitat- and site-specific natal contributions and informs Walleye management in Missouri River reservoirs, particularly broodstock collection, habitat protection and restoration, and harvest regulations.
DOI: 10.1080/02755947.2015.1135214