First Insights Into the Vertical Habitat Use of the Whitespotted Eagle Ray Aetobatus narinari Revealed by Pop‐up Satellite Archival Tags

• Main Authors: Brewster, L. R., Cahill, B. V., Burton, M. N., Dougan, C., Herr, J. S., Norton, L. Issac, McGuire, S. A., Pico, M., Urban-Gedamke, E., Bassos-Hull, K., Tyminski, J. P., Hueter, R. E., Wetherbee, Bradley M., Shivji, Mahmood S, Burnie, N., Ajemian, M. J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NSUWorks 2020
• Subjects: Bermuda; Biotelemetry; Diel vertical migration; Elasmobranch; Gulf of Mexico; PSAT; Marine Biology; Oceanography and Atmospheric Sciences and Meteorology; North Atlantic
• Online Access: https://nsuworks.nova.edu/occ_facarticles/1127; https://nsuworks.nova.edu/cgi/viewcontent.cgi?article=2137&context=occ_facarticles

The whitespotted eagle ray Aetobatus narinari is a tropical to warm‐temperate benthopelagic batoid that ranges widely throughout the western Atlantic Ocean. Despite conservation concerns for the species, its vertical habitat use and diving behaviour remain unknown. Patterns and drivers in depth distribution of A. narinari were investigated at two separate locations—western North Atlantic (Islands of Bermuda) and Eastern Gulf of Mexico (Sarasota, Florida, USA). Between 2010 and 2014, seven pop‐up satellite archival tags (PSATs) were attached to A. narinari using three methods: a through‐tail suture; external tail‐band; and through‐wing attachment. Retention time ranged from 0–180 days, with tags attached via the through‐tail method retained longest. Tagged rays spent the majority of time (82.85 ± 12.17% S.D.) within the upper 10 m of the water column and, with one exception, no rays travelled deeper than ~26 m. One Bermuda ray recorded a maximum depth of 50.5 m suggesting that these animals make excursions off the fore‐reef slope of the Bermuda Platform. Individuals occupied deeper depths (7.42 ± 3.99 m S.D.) during the day versus night (4.90 ± 2.89 m S.D), which may be explained by foraging and/or predator avoidance. Each individual experienced a significant difference in depth and temperature distributions over the diel cycle. There was evidence that mean hourly depth was best described by location and individual variation using a generalized additive mixed model approach. This is the first study to compare depth distributions of A. narinari from different locations and describe the thermal habitat for this species. Our study highlights the importance of region in describing A. narinari depth use, which may be important when developing management plans, whilst demonstrating that diel patterns appear to hold across individuals.