Using Radiotelemetry to Compare the Initial Behavior and Mortality of Hatchery-Reared and Wild Juvenile Florida Bass

Abstract

Stocking evaluations for pellet-reared, advanced-fingerling Largemouth Bass Micropterus salmoides often result in low contribution and survival, but little information exists on their survival and behavior soon after release. This study investigated the behavior and mortality of pellet-reared, advanced-fingerling (90–120 mm TL) Florida Bass M. floridanus immediately after they were stocked in Lake Carlton, Florida. A radiotelemetry experiment was conducted to compare initial movement, habitat use, growth, and mortality between stocked hatchery and wild fish. In year 1, we inserted radio transmitters into 50 hatchery fish; in year 2, we tagged 30 hatchery fish and 20 wild fish. All mortality we observed for hatchery fish (from both years) resulted from predation by fish and birds, and most occurred in the first 7 d after tagging. When compared directly with tagged wild fish (n = 20), tagged hatchery fish (n = 30) exhibited greater movement (75 and 124 m/d, respectively), greater proportion of locations offshore (8% and 23%, respectively), slower growth (1.73% and 0.41% of their body weight gained per day, respectively), and higher predation (47% and 0%, respectively). Results of this study suggest that pellet-reared, hatchery Florida Bass suffer more predation than wild bass of similar size initially following their release into the lake. Causes of predation could include less-developed antipredator skills and inefficiency in foraging observed through greater movement, as well as the use of offshore habitat and slower growth. We recommend research that investigates acclimating advanced-fingerling Florida Bass to predators and live prey before release to determine whether initial predation can be reduced after stocking.

Received May 29, 2015; accepted December 4, 2015

ACKNOWLEDGMENTS

Rick Stout, Michael Matthews, and the rest of the staff at the Florida Bass Conservation Center provided all hatchery Florida Bass used in this study. Scott Bisping, Kris Knault, Brad Fontaine, and many other biologists from the Eustis Research Laboratory assisted with field tracking. Ryan Buyton analyzed the GIS data, and Jason Dotson provided valuable edits to previous versions of this manuscript. This study was supported by funding from the Sportfish Restoration Program under grant FL-F-131 from the U.S. Fish and Wildlife Service.

Notes

¹ The taxonomic status of this species is not settled. The American Fisheries Society Committee on Names of Fishes still regards Florida Bass as a subspecies of Largemouth Bass, known as Florida Largemouth Bass Micropterus salmoides floridanus.