Riders on the storm: loggerhead sea turtles detect and respond to a major hurricane in the Northwest Atlantic Ocean

Abstract

Background Extreme weather events, including hurricanes, have considerable biological, ecological, and anthropogenic impacts. Hurricane Irene caused substantial economic damage when it hit the Mid-Atlantic Bight (MAB) off of the eastern United States in August of 2011. The MAB is highly stratified during the summer when a strong thermocline separates warm, surface water from deep, cold water, and this oceanographic phenomenon makes modeling hurricane strength difficult. Loggerhead sea turtles ( Caretta caretta ) forage in the MAB primarily during the stratified season and their dive behavior to the bottom allows them to experience the oceanographic conditions of the entire water column. Methods In this study, we analyzed the movements and dive behavior of juvenile and adult-sized loggerhead sea turtles ( n = 18) that were foraging in the MAB as Hurricane Irene moved through the region. The satellite tags deployed on these turtles transmitted location data and dive behavior as well as sea surface temperature (SST) and temperature-depth profiles during this time. Results Behavioral and environmental shifts were observed during and after the hurricane compared to conditions before the storm. During the hurricane, most of the turtles ( n = 15) moved north of their pre-storm foraging grounds. Following the storm, some turtles left their established foraging sites ( n = 8) moving south by 7.3–135.0 km, and for the others that remained ( n = 10), 12% of the observed dives were longer (0.54–1.11 h) than dives observed before the storm. The in situ data collected by the turtle-borne tags captured the cooling of the SST (Mean difference = 4.47°C) and the deepening of the thermocline relative to the pre-storm conditions. Conclusions Some of the loggerhead behavior observed relative to a passing hurricane differed from the regular pattern of seasonal movement expected for turtles that forage in the MAB. These data documented the shifts in sea turtle behavior and distribution during an ecosystem-level perturbation and the recorded in situ data demonstrated that loggerheads observe environmental changes to the entire water column, including during extreme weather events.

Movements of marine and estuarine turtles during Hurricane Michael

“…Despite the recordbreaking winds and extreme storm surge, tags on five of the six turtles tracked during landfall continued transmissions post-storm thereby confirming turtle survival. There are multiple strategies that turtles utilize to survive during and after extreme weather events including altering dive behavior, increasing home range size and shifting habitat use [29][30][31] . These studies have typically involved larger samples sizes 30 or have documented long-distance movements 31 .…”

“…There are multiple strategies that turtles utilize to survive during and after extreme weather events including altering dive behavior, increasing home range size and shifting habitat use [29][30][31] . These studies have typically involved larger samples sizes 30 or have documented long-distance movements 31 . The turtles tracked in SJB during Hurricane Michael showed no large-scale movements or changes in behavior in response to the storm.…”

A Systematic Review of Acoustic Telemetry as a Tool to Gain Insights Into Marine Turtle Ecology and Aid Their Conservation

“…In addition, acoustic telemetry has shown that some juvenile marine turtles actively select for manmade structures over natural habitats, which could prompt small-scale shifts in habitat use as the number of jetties and other shoreline stabilization structures increase with rising sea levels (Renaud et al, 1995;MacDonald et al, 2013;Crear et al, 2017;Matley et al, 2019;Oppenheimer et al, 2019). As storm frequency and intensity increase, knowledge of marine turtles' response and survivability to storms is important (Fuentes and Abbs, 2010;Fuentes et al, 2019;Crowe et al, 2020). Matley et al (2020) and Lamont et al (2021) assessed this response when separate Category 5 hurricanes moved over their passive array study sites.…”

Detection and population genomics of sea turtle species via noninvasive environmental DNA analysis of nesting beach sand tracks and oceanic water

“…We recently employed eDNA‐based approaches to study the shedding of the virus (ChHV5) associated with this disease, and these results, combined with the results of this study, can provide insight into the health and population status of wild sea turtles inhabiting our study sites (Farrell, Yetsko, et al, 2021; Yetsko et al, 2020). With increasing habitat degradation and vulnerability to threats, already threatened sea turtle populations are at increasing risk, therefore pathogen and population monitoring is crucial to aiding their survival (Crowe et al, 2020; Eastman et al, 2020; Gomez‐Ramirez et al, 2020; Marn et al, 2017). In this study we developed and validated qPCR assays in a sea turtle rehabilitation setting and we conducted field trials to detect, quantify and assess sea turtle species ( C .…”