The silver king in the Magic City: Observation of Atlantic tarpon Megalops atlanticus aggregation off Miami, Florida.

Abstract

Due to the logistical and financial challenges in studying migratory marine species, there is relatively limited knowledge of the reproductive biology, behavior, and habitat use of many ecologically important marine megafauna species, including the Atlantic tarpon Megalops atlanticus. Here, we present a novel observation using consumer-grade aerial drones to observe, quantify the scale of, and classify behaviors within a previously unreported tarpon aggregation (N = 182) over the course of a 2-day fish aggregation event. After the event, we analysed and compared observed behaviors (e.g., cruising and clustering) with those of other fish species with well-documented reproductive behaviors, revealing behaviors potentially consistent with courtship, leading us to believe this to be a possible spawning aggregation or aggregation of reproductive/migratory significance. This aggregation occurred in highly altered and urbanized habitat off the coast of South Florida, during the winter, and outside of tarpon's previously reported spring and summer spawning season. Although few studies to date have used drones to monitor teleosts, this study reinforces their potential value as a tool for monitoring fish populations, behavior, and movement.