Abstract

The spotted eagle ray, Aetobatus narinari, is a large, wide-ranging benthopelagic ray found in coastal and estuarine ecosystems in the Atlantic, including the Gulf of Mexico and Caribbean Sea. Although this species is protected in Florida waters, it is targeted in fisheries in Mexico, Cuba, and Venezuela, causing concern for its conservation status due to decreasing population trends. Understanding movement patterns is crucial to determining the mechanisms of population structure in spotted eagle rays. Preliminary satellite and conventional tagging data indicate these rays are capable of extensive migrations. As part of an ongoing tagging study, some individuals have been recaptured over weeks to years in Sarasota, Florida, suggesting the species exhibits a degree of fidelity to the region. We acoustically tagged spotted eagle rays to examine fine-scale movements in and out of coastal estuaries along the eastern Gulf of Mexico, while also monitoring longer distance movements via collaborative acoustic telemetry networks (i.e., iTAG). During spring 2016 (n = 15) and 2017 (n = 9), 24 spotted eagle rays were fitted with Vemco V16 acoustic transmitters and monitored with acoustic gates covering inlet passes in Sarasota Bay. Most detections of study animals ranged from weeks to months in three passes and several tagged individuals were detected in collaborative network arrays up to 100 km away. All rays tagged in spring 2016 left the Sarasota Bay area when a harmful algal bloom (i.e., Karenia brevis) appeared in September 2016, with 8 of 15 rays returning in spring 2017. Understanding these movement patterns in relation to environmental factors is important for management of this species in the U.S. and neighboring countries.

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