Keywords:In-water videography Cold water foraging Interspecies interactions Intraspecies interactions Baited remote underwater video system (BRUV) This study represents the first documented use of a remotely operated vehicle (ROV) to actively track sea turtles in situ. From 2008 to 2014, an ROV was deployed to track the at-sea behavior of loggerhead turtles in the Northwest Atlantic Ocean. Seventy turtles were tracked, totaling 44.7 h of direct turtle footage. For all attempts, usable video with a turtle retained in view for a minimum of 30 s, was produced at a rate of 43.5% of effort. Turtles were first spotted from the boat, and then when the turtle was within~50 m of the boat, the ROV was deployed to track the turtle for as long as possible. Tracking durations reached up to 426.1 min. Tracked turtles often remained within~10 m of the surface; however loggerheads were tracked to the seafloor on 12 occasions. Turtles were filmed foraging both pelagically and benthically, even though bottom temperatures reached as low as 7.1°C. A range of inter-and intra-species interactions were also captured. Several varieties of fish remained associated with individual turtles for extended periods of time, even during benthic foraging dives. Additionally, a variety of social interactions between loggerheads were documented. Generally these interactions were filmed occurring near the ocean surface. Overall, using the ROV provided great insight into loggerhead at-sea behavior, otherwise unattainable using previously established techniques.

Sea turtles are vulnerable to climate change impacts in both their terrestrial (nesting beach) and oceanic habitats. From 1982 to 2012, air and sea surface temperatures at major high use foraging and nesting regions (n = 5) of loggerhead turtles (Caretta caretta) nesting in Greece have steadily increased. Here, we update the established relationships between sea surface temperature and nesting data from Zakynthos (latitude: 37.7°N), a major nesting beach, while also expanding these analyses to include precipitation and air temperature and additional nesting data from two other key beaches in Greece: Kyparissia Bay (latitude: 37.3°N) and Rethymno, Crete (latitude: 35.4°N). We confirmed that nesting phenology at Zakynthos has continued to be impacted by breeding season temperature; however, temperature has no consistent relationship with nest numbers, which are declining on Zakynthos and Crete but increasing at Kyparissia. Then using statistically downscaled outputs of 14 climate models assessed by the Intergovernmental Panel on Climate Change (IPCC), we projected future shifts in nesting for these populations. Based on the climate models, we projected that temperature at the key foraging and breeding sites (Adriatic Sea, Aegean Sea, Crete, Gulf of Gabès and Zakynthos/Kyparissia Bay; overall latitudinal range: 33.0°—45.8°N) for loggerhead turtles nesting in Greece will rise by 3–5°C by 2100. Our calculations indicate that the projected rise in air and ocean temperature at Zakynthos could cause the nesting season in this major rookery to shift to an earlier date by as much as 50–74 days by 2100. Although an earlier onset of the nesting season may provide minor relief for nest success as temperatures rise, the overall climatic changes to the various important habitats will most likely have an overall negative impact on this population.

We established reference intervals for blood biochemistry and haematology of loggerhead turtles captured off the Mid-Atlantic coast of the USA. This assessment of blood variables in healthy, wild loggerhead turtles allows for comparisons with turtles impacted by anthropogenic and environmental threats, as well as turtles sampled in different habitats and life stages.