Synchronous fish recruitment can occur at broad geographic scales due to dispersal and similarities in climatic conditions. Herein, we investigated recruitment of Silver Carp Hypophthalmichthys molitrix across four major tributaries of the Mississippi River (MR). Year-class strength and synchrony of nine populations was indexed using correlated catch-curve residuals among sites and related to local- and regional-scale climatic conditions. Recruitment was not synchronous (mean ρ = -0.08 ± 0.13 SE) across the MR watershed, implying the importance of local environmental conditions. Recruitment was negatively related to variability in river discharge and base flow while positively related to river discharge during the reproductive period, indicating that extended periods of elevated river discharge aid in regulating recruitment. River discharge and temperature were correlated among sites; yet only river discharge was correlated (r = 0.59) with Carp population synchrony, indicating that river discharge synchrony can synchronize Carp recruitment. In contrast, recruitment was not related to regional climatic conditions, indicating that local environmental factors have more influence on recruitment. Our results suggest that MR Carp populations asynchronously recruit as a result of asynchronized river discharge, adding to our understanding of recruitment dynamics of a highly invasive species.
|Original language||English (US)|
|Title of host publication||AFS - 147th Annual Meeting of the American Fisheries Society, August 20-24, 2017, Tampa, Florida|
|State||Published - 2017|