We are studying the spatiotemporal abundance, migratory patterns, and habitat use of the endangered whitespotted eagle ray, Aetobatus narinari, using a combination of techniques, including aerial surveys, drone footage, and passive acoustic telemetry. Aetobatus narinari is distributed throughout the Atlantic and is commonly found in nearshore waters off the coasts of Florida, where it is listed as a protected species. Previous studies show potential subpopulation structuring in Florida, where populations in the Gulf of Mexico exhibit migratory behavior whereas those in the western Atlantic appear to be resident. Information on the spatiotemporal distribution and habitat use of A. narinari is limited to the east and west coasts of the state and is lacking within the Florida Keys. Therefore, the goal of this study is to determine the abundance, distribution, migratory patterns, and habitat use of A. narinari in the upper and middle Florida Keys. It is important to understand population abundance, habitat use, and migratory patterns of endangered species for effective management throughout their range, especially for a species capable of long-distance migrations through multiple exclusive economic zones (EEZ). Aerial surveys are conducted biweekly from Government Cut, Miami to Old Bahia Honda Bridge (185km). Preliminary results show rays are present in the Florida Keys during all months, but a peak in abundance occurs during March-April. Distribution varies along the transect, with high concentrations of rays found near Key Biscayne and Tavernier Key during certain times of the year. These preliminary results suggest a potential seasonal increase in abundance of A. narinari in the Keys with some areas of higher concentrations. The continuation of aerial surveys and the addition of drone filming and acoustic tagging will provide further data on the spatiotemporal distribution and habitat use of rays in the Florida Keys, which will contribute important information for the effective management of this species.

We are testing the efficacy of a magnetic shark deterrent known as the Sharkbanz Zeppelin. This device is a neodymium permanent magnet that is thought to be sensed by a shark through electromagnetic induction and presents a strong, novel stimulus that startles the shark. This work is done utilizing baited remote underwater videos, which allows one to collect data on the behavior of different shark species towards the device. In addition, we are mapping the magnetic field output of the device and creating a model to examine the effective range of the magnetic field. If this magnetic deterrent is effective, it could be used as a potential mitigation mechanism for shark depredation, which leads to the loss of income for fisheries and a decline in both shark and target fish populations.

Blacktip sharks aggregate by the thousands in nearshore waters of southeast Florida every winter. For over a decade we have employed aerial surveys with airplanes and drones, acoustic and satellite telemetry, underwater video monitoring, and animal-borne data loggers to examine the distribution and movements of sharks as they overwinter along our coast and migrate up the eastern seaboard. We have found that these sharks have shifted their distribution to higher latitudes in response to warming oceans. In the future, southeast Florida might actually be deprived of these seasonally important predators, which could have cascading effects throughout the marine ecosystem.