Abstract
The application of satellite tracking technologies to sharks has been critical to our understanding of the drivers of their movements in time and space for several years. With rapidly warming waters driving changes to species distribution, it’s a critical time for researchers to collect environmental and ecological data from species that regulate marine ecosystems. Selecting the correct ‘tool for the job’ however is challenging, as closely related species can exhibit different movement characteristics and morphologies that influence the required hardware. Tiger sharks (Galeocerdo cuvier) and great hammerhead sharks (Sphyrna mokarran) are two such species, occupying many of the same coastal niches in tropical waters. As regular surfacers with short dorsal fins, deployment of fin-mounted Wildlife Computers SPOT tags proved to be an appropriate tool for monitoring tiger shark horizontal movements at fine and coarse scales. However, application of the same tag configuration on great hammerheads resulted in failure to receive usable data. After reconsideration of hammerhead biology, a novel towed-tag approach was adopted, resulting in fine-scale habitat use data for the first time in this species. Careful consideration of study species morphology is a key factor in hardware selection and configuration in ecological applications, so research objectives can be achieved.