Postrelease Mortality of Angled Tarpon in Puerto Rico

Abstract

Tarpon Megalops atlanticus is a popular and economically important inshore sport fish in Puerto Rico, and the pursuit of this species by local anglers and tourists contributes to the economy. This species is managed as a no-take fishery, which aims to preserve populations by catching and releasing fish that would otherwise be subjected to harvest and removal from the population. The approach assumes minimal mortality and/or reduced fitness of released fish, yet the process of angling can produce many sublethal side effects or direct mortality. In this study, charter angling for Tarpon in the San Juan lagoon system in Puerto Rico was examined to determine postrelease mortality. Angled fish were externally tagged with acoustic transmitters and relocated periodically to determine the fate after release. Postrelease mortality was at least 4.5% (two fish observed dead) and at most 18.2% (observed dead plus classified dead based on lack of movement; confidence interval [CI] = 7.5-28.9%). Some tag loss was observed, which could have artificially elevated classified mortality estimates. Potential factors that contribute to mortality are discussed and compared to the literature. Hook type, gear action, landing procedures, and air exposure were key areas of possible improvement. Recommendations to minimize fish harm during angling include the use of heavier action gear to reduce fight time, a circle hook requirement for live bait to reduce deep hooking, maintaining fish in the water during landing and photography, and limiting air exposure to 2 min or less if fish are removed from the water.