Pregnant Shark Migration Tracked from Space
This spring, Forbes Magazine published an article on an amazing international collaboration.
For the first time, researchers have been able to record in near real-time the migration of a pregnant scalloped hammerhead shark (Sphyrna lewini) from the Galápagos Islands in Ecuador to Isla del Coco in Costa Rica, located over 435 miles (700 kilometers) away.
This collaboration: the Charles Darwin Foundation’s shark ecology project, the Galapagos National Park Directorate (GNPD), Save Our Seas Foundation Shark Research Center, and Guy Harvey Research Institute at Nova Southeastern University (USA) have teamed up to study the migrations and population genetics of the world’s largest scalloped hammerhead shark aggregation.
Scalloped hammerhead sharks are a globally endangered species. It inhabits different habitats throughout its life cycle, making information about their movement and use of habitat disjointed at best. Enter a special hammerhead shark: Cassiopeia. Measuring about 8.2 feet (2.5 meters) long, this pregnant female was tagged in February of this year during an expedition to Darwin Island.
Satellite tracking data revealed that after swimming north of Darwin Island for about 10 days, Cassiopeia started swimming eat until she reached Isla del Coco. The trek Cassiopeia made between the two islands means she covered around 390 nautical miles (700 km) in just under 14 days, travelling an approximate of 28 nm (50 km) per day. While previous studies have documented inter-island movements of hammerheads using passive acoustic tags, the tags weren’t able to capture the precise pathways the sharks would take. With satellite tags, scientists were able to see exactly the route she went.
HCAS biology faculty member Mahmood Shivji, Ph.D., director of the Guy Harvey Research Institute and Save Our Seas Foundation Shark Research Center stated, “The data being collected in this study will be key for establishing a flexible management system that provides this protection at precisely the right places and times.”