![]() Wind speed had a linear relationship with pup counts and > 50% more pups were counted at 5 m/s than at 1 m/s. Pup counts grew from the onset of the observation period and were predicted to peak on June 22. The best-performing model included date and wind speed. The effects of weather conditions and timing of surveys on counts were analyzed by generalized additive mixed models. ![]() Drone surveys of these two haul-outs were conducted throughout the breeding seasons during 2017-2019. Surveys of harbor seals to assess pup production in Denmark are conducted at the assumed breeding season peak between 9 and 15 hr at winds 95% of pups are born at two haul-out sites situated 4 km apart. Overall, UAVs provide a low-cost approach of quantifying the flexibility of marine animal behaviour, allowing us to integrate information on abundance to establish how individuals re-spond to the presence of other organisms and the immediate environment. The complexity of behaviours revealed by direct observations of sea turtles and animal-borne cameras can also be examined using UAV footage, complementing studies using electronic tags, such as time-depth recorders and satellite transmitters. For instance, UAV surveys can reveal turtle densities and hence operational sex ratios of sea turtles, which could be linked to levels of multiple paternity.įurthermore, embedding UAV surveys within a mark-recapture framework will enable improved abundance estimates. ![]() We discuss the emerging possibilities of how UAVs can become part of the standard methodologies for sea turtle ecologists through combining information on abundance and behaviour. UAV studies of all three groups primarily focus on obtaining estimates of abundance, distribution and density, while some studies have provided novel insights on the body condition, movement and behaviour of individuals (including inter-specific interactions). We review how unmanned aerial vehicles (UAVs), often referred to as drones, are being deployed to study the abundance and behaviour of sea turtles, identifying some of the commonalities and differences with studies on other marine vertebrates, including marine mammals and fish. ![]()
0 Comments
Leave a Reply. |