Atlantic Tarpon Megalops atlanticus support a catch-and-release fisheries in the United States and other territories such as Puerto Rico. Survival of angled fish is imperative to catch-and-release fishing yet numerous factors have yet to be looked at over a timescale to determine if laboratory and wild Puerto Rico tarpon experience increased stress and risk of mortality. To evaluate stress in simulated catch-and-release angling, laboratory trials were conducted over a 24-hour time scale with 2 varying intensities of simulated angling and various physiological parameters were explored. Blood samples concluded that simulating angling only had an interaction effect in time and fishing intensity in the factor of osmolality. In field studies, tarpon studied physiologically gave inconclusive results due to lack of a time scale. Field studies tracking mortality were completed by acoustic telemetry of angled fish in the San Juan Lagoon network. Studies resulted in a mortality that ranges from 4.5-20.5%.

Estuarine marshes are generally considered to be productive but not necessarily diverse ecosystems. During 24 consecutive months, I collected 65,000 fishes and decapods comprising over 65 species from the New Orleans Land Bridge, an estuarine salt marsh. My research details the distribution of nekton across five contiguous but geomorphically different regions, which I defined as “Areas”. This factor “Area” was significant in explaining community composition differences in 11 of the 24 months I evaluated. That is, during those 11 months community structure was different among the Areas. Specific “month” was also found to be a significant factor as community structure was found to differ among the months. No consistent abiotic factors were associated with community structure. These observations imply that a different set of factors are associated with community structure at the Area level than at the microhabitat level. Sampling of nekton in shallow estuarine salt marsh habitats was difficult. The cast net is a useful gear type for this type of sampling and can be readily standardized for each operator. Standardization of the area covered by the net allows density of collected nekton to be calculated. Little is known about the life cycle of one important estuarine dependent sport fish, tarpon (Megalops atlanticus), in southeastern Louisiana. This research details the presence of the major life stages of the species in Louisiana and suggests that it is capable of completing its life cycle in State waters. The presence of a spawning capable female and male tarpon is documented.

Atlantic tarpon are sought after because of their fighting ability on various tackle and support a popular, lucrative and predominantly catch-and-release recreational fishery in Florida. They are not commercially harvested or consumed by the general public, therefore assessing effects of catch-and-release angling on tarpon survival is critical to a sustainable fishery. Tarpon caught on artificial breakaway jig and traditional live bait fishing charters in Boca Grande Pass (n=42) and trips from the recreational fishery of Tampa Bay (n=40) were tagged with ultrasonic transmitters and tracked up to 6 hours immediately following release to estimate post-release mortality. Of the 82 tagged tarpon, 11 suffered mortality as inferred from movement patterns (or lack thereof) or visual confirmation (i.e. shark attacks) which yields a combined total estimated catch-and-release mortality rate of 13% (95% confidence interval: 6-21%). There was no significant difference in mortality between the two estuarine systems. Associations between tarpon mortality and angling duration, handling time, fish length, bait type (artificial versus natural), and hook type (circle versus "J") were not significant. Hook location (foul-hooking) and swimming condition at release were significant factors on tarpon mortality (P<0.05). Shark predation was the primary cause of post-release mortality (64%). Excluding predation, the overall mortality rate was estimated at 5% and attributed to poor handling and irreparable physiological damage from angling. Angling events will cause anaerobic activity resulting in physiological disruptions that may have consequences compromising the health and survival of tarpon. Both adult (mature, >70 pounds, 31.8 kg) and sub-adult (sexually immature, <20 pounds, 9 kg) tarpon support Florida's recreational fishery, so maximizing post-release survival and minimizing sub-lethal stress effects of both size classes are critical to their sustainability. In this study, stress responses after exhaustive exercise (angling) were measured using an array of blood chemistry parameters, including hematocrit, hemoglobin, and plasma glucose, lactate, sodium, potassium, chloride, calcium, phosphorus, magnesium and cortisol. Angled, adults (n=45) were compared to large tarpon in a resting state (controls, n=6). Angled, sub-adults (n=28) were compared to those in a resting state (n=9). Adult tarpon were then compared to sub-adults to determine any size-related, intra-species variation in stress responses after angling. Finally, because smaller tarpon are logistically easier to handle and may be subjected to prolonged air exposure by anglers for hook removal or photographs, we evaluated the effect of 60 seconds of air exposure with horizontal (n=9) or vertical (n=9) handling out of the water relative to non-air exposed (n=10) fish in angled sub-adult tarpon. Associations and interactions among the blood chemistry responses of tarpon from each treatment to angling duration, handling time, body size and environmental factors related to each capture event were evaluated using a non-parametric, multivariate redundancy analysis. The duration of the angling event had a positive effect on responses of some parameters, and responses were more extreme in adult tarpon than sub-adults. The exception was cortisol which was significantly higher in sub-adults. Environmental parameters were less influential than angling and handling on observed physiological responses. Sub-adults showed no difference in physiological responses among handling treatments with and without air exposure and exhibited no short term mortality. Using appropriate tackle and gear to reduce fight times and handling should help minimize metabolic and acid-base imbalances. Tagging studies coupled with physiology can be a valuable tool for estimating post-release mortality and secondary stress responses of game fish, especially for large species that might be difficult to maintain in floating pens or tanks. Yet adverse effects of catch-and-release angling could also have population level consequences. Future studies should integrate biology and fish physiology to evaluate post-release recovery windows and establish lethal thresholds to provide potential predictive capability of mortality. In general, it appears that sub-adult and adult Atlantic tarpon along the Gulf coast of Florida can recover from physiological disturbances incurred during routine catch-and-release angling events in the recreational fishery when they are released in the absence of large predators. The anglers themselves can play a key role in tarpon conservation.