A Strategy for Increasing Gill‐Net Catch Rates and Minimizing Sampling Mortality of Alligator Gars

Abstract

AbstractManagement of the Alligator Gar Atractosteus spatula has been hampered by the lack of sampling methods that can efficiently reveal population characteristics or minimize incidental sampling mortality. In a 3‐year evaluation of the Alligator Gar population in Choke Canyon Reservoir, Texas, we documented changes in sampling methodology that produced an eightfold increase in multifilament gill‐net catch rates (from 0.66 to 5.10 fish/h). The increased sampling efficiency was attributed to the development of an aggressive‐predator sampling strategy over the study period; our highest catch rates were achieved by (1) observing surfacing fish before net deployment and (2) relocating to a new sampling site when catch rates were less than 1 fish/h. This aggressive strategy resulted in shorter net soak times, which reduced incidental net mortalities; nets soaking less than 30 min produced zero mortalities. Our results suggest that the aggressive‐predator strategy is suitable for the majority of Alligator Gar sampling objectives (e.g., collection for age and growth and mark–recapture), which will improve the ability to manage Alligator Gar populations.Received August 18, 2014; accepted February 4, 2015