Meeting Abstract
The Gulf of Mexico’s recreational fisheries has been estimated to provide in excess of $7 billion annually, and sportfish species like Atlantic tarpon (Megalops atlanticus) and red drum (Sciaenops ocellatus) are major contributors. Catch-and-Release (CAR) angling was implemented to help protect sportfish species, and the associated economic interests of stakeholders, yet the effectiveness of CAR can vary between species and ecosystems. Tarpon are unique among marine fishes because they can breathe air; however, their reliance on air breathing remains uncertain, which has important implications for CAR. As such, this study has two goals: 1) to determine if air-breathing behavior is facultative or obligate in tarpon, and 2) to assess the importance of air-breathing to recovery from exhaustive exercise. Juvenile tarpon were first observed via video for 1 h period in normoxia and hypoxia (20% oxygen saturation) to categorize air-breathing behavior. Consistent with facultative air-breathing, tarpon significantly elevated air-breathing rate when exposed to hypoxia. To simulate CAR events, individuals were chased to exhaustion and sampled, or allowed to recover for 1 or 4 h with or without access to the surface. A similar protocol was undertaken for red drum to provide a comparison to a non-air-breathing sportfish. Each individual was sampled for blood, white muscle, gills, and heart and assessed for a panel of common indices of exercise stress. Preliminary results suggest that tarpon begin to recover from exercise by 4 h post-exercise, with no clear benefits of having access to the surface. This was similar to the recovery profile exhibited by red drum. As such, no special considerations are needed in CAR procedures to accommodate the air-breathing physiology of tarpon.
