Seasonal Mortality and Movement Patterns of White Bass in a Southeastern U.S. Reservoir

Abstract

Little is known about the fundamental aspects of the life history, ecology, and population dynamics of White Bass Morone chrysops in southern U.S. reservoirs, making management of this species difficult. Recent concerns from the North Carolina Wildlife Resources Commission regarding potential population declines in North Carolina prompted an effort to expand the knowledge base of White Bass in reservoirs. Our study aimed to address mortality (fishing mortality, F, and natural mortality, M) as one potential mechanism related to their population declines and to assess seasonal movement and habitat patterns of reservoir White Bass throughout the year using telemetry. We implanted acoustic transmitters into 50 White Bass in spring 2012 and into 25 White Bass in spring 2013. B. Everett Jordan Reservoir, a relatively shallow and eutrophic reservoir located in the Piedmont region of North Carolina, was separated into four different subbasins that were surveyed each month for tagged fish. Fish were monitored using an array of passive receivers and monthly active tracking surveys. A monthly capture history was used as the input for a multistate capture–recapture model in a Bayesian framework to estimate instantaneous monthly mortality rates. Total annual mortality was 76%. The annual exploitation rate (60%) was greater than the natural mortality rate (15%); however, both F and M exhibited seasonal variation and peaked during spring months in 2012 and 2013. White Bass did not use any specific habitat type but were located relatively far from shore and in deep water during cooler months. The use of subbasins in the system was not equal; other than during the spawning run White Bass concentrated in several areas within the two deepest subbasins of the reservoir. Overall, the high F observed in the spring suggests that adjusting the current liberal harvest limits will help mitigate mortality and aid in the management of reservoir White Bass populations.

Received January 21, 2016; accepted May 4, 2016 Published online August 5, 2016

ACKNOWLEDGMENTS

This research was funded by the North Carolina Wildlife Resources Commission through Federal Aid in Sport Fish Restoration grant F101. We thank Brian McRae, Christian Waters, Corey Oakley, and Jessica Baumann from the North Carolina Wildlife Resources Commission for their role in the development of this project and for their field assistance, and Joseph Hightower from North Carolina State University for the use of a telemetry mortality model he developed and for the support he provided along the way. Finally, we thank the all the members of the Fisheries Ecology and Aquatic Sciences Laboratory, especially Daniel Brown, Dylan Owensby, and Zachary Feiner, as well as many other graduate students at North Carolina State University for their voluntary laboratory and field assistance.