Components of Mortality within a High-Release Recreational Fishery

Thursday, August 23, 2012: 2:00 PM
Meeting Room 7,8 (RiverCentre)
Janice Kerns , Fisheries and Aquatic Science Program, University of Florida, Gainesville, FL
Mike Allen , School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL
Joseph E. Hightower , Biology, U.S. Geological Survey, North Carolina State University, Raleigh, NC
Catch-and-release mortality has been exhaustively studied for many high-release recreational sport fish such as largemouth bass Micropterus salmoides.  However, little work has explored the cumulative impact of catch-and-release mortality on fish abundance.  We used a combined telemetry - tag return approach to estimate all components of total mortality including (a) natural mortality and (b) total fishing mortality sub-divided into harvest, catch-and-release and tournaments components within a popular fishing lake in north Florida.  Our analyses were based on fates of 150 largemouth bass tagged with external high reward dart tags and/or internal radio transmitters tracked for nine months.  Annual estimates of directed instantaneous fishing mortality ranged from 0.05 (SD = 0.03) to 0.24 (SD = 0.07) for the conventional and telemetry tags, respectively.  Estimates of instantaneous fishing mortality associated with tournament and catch and release were both 0.07 (SD=0.04). An estimate of instantaneous natural mortality from the telemetry data (0.46, SD = 0.09) was within the expected range when compared to other published estimates.  Our results indicate that non-harvest sources of mortality can be a significant source of fishing mortality in high-release fisheries, even if overall discard mortality rates are not substantial.