The scalloped hammerhead shark is the only large shark species that aggregates in highly organized and complex social groups, as seen in many places around the world. One such aggregation site exists off southeastern Japan, around a large seamount near the city of Mikomoto. Since 2015, we have been studying the movements, habitat use, and social interactions of this aggregation of hammerhead sharks. To monitor the movements of this large aggregation of pelagic (open ocean) sharks, we use a combination of acoustic and satellite telemetry tagging. Briefly, this includes free-diving down into large schools of the sharks and affixing tags to their bodies via spearguns. Each tag has its own unique code which is ‘pings’ every 60-180 seconds, and these transmissions are picked up and recorded by an array of acoustic hydrophones that our team affixed to the ocean floor. In Summer 2016 we recovered the data from our first year of tracking, recording an >20,000 detections, with the tags remaining on the sharks for up to and over a year. Our first expedition in 2015 served as the first long-term behavioral study of sharks in Asia, an important first for shark conservation worldwide. The project was featured as part Outside Magazine’s February 2016 cover story on our project contributor Mark Healey. This project is currently in its third year.
Project partners and contributors include: Dr. David Jacoby (Zoological Society of London), Dr. Yannis Papastamatiou (Florida International University), Dr. Yuuki Watanabe (National Institute of Polar Research), Tre’ Packard (Pangeaseed Foundation), Mark Healey (Healey Water Ops), and Dr. Neil Hammerschlag (University of Miami).