On April 8th, the National Geographic channel premiered its latest masterpiece:Shark Superhighways, by Tom Lucas Productions. This one-hour documentary follows Dr. Pete Klimley, Director of the Biotelemetry Lab at UC Davis, and pioneer of shark research, during a cruise at Darwin and Wolf, in the Galapagos Islands.
Do hammerheads use changes in geomagnetic fields to navigate throughout the oceans?
On April 8th, the National Geographic channel premiered its latest masterpiece: Shark Superhighways, by Tom Lucas Productions. This one-hour documentary follows Dr. Pete Klimley, Director of the Biotelemetry Lab at UC Davis, and pioneer of shark research, during a cruise at Darwin and Wolf, in the Galapagos Islands.
The film shows how the team (including members from Charles Darwin Foundation and Galapagos National Park Service) set up an array of listening stations around Darwin and Wolf, and tag several hammerheads with ultrasonic pingers, in order to understand their site fidelity and movements around the islands.
The team also tracked a female hammerhead for 48 hours. They expected it to move out into the open ocean at night to feed, as Prof. Klimley found in Baja California in previous studies. However, they were surprised to find that the shark remained in the same general area for the entire study period.
The crowning point of the documentary shows the team successfully catching 2 male hammerheads, bringing them onboard, fitting them with satellite tags and releasing them back into the water unharmed.
This had never been done before, and previous efforts to successfully catch hammerheads at the same site had always resulted in Galapagos sharks getting caught.
The results showed that one male travelled into the centre of the archipelago, and remained there for two months, until the tag stopped transmitting, whereas the other shark swam in a north-westerly direction for several hundred miles out into the ocean.
The film poses the question as to how these sharks navigate such distances. Prof. Klimley believes that they can detect geomagnetic gradients in the
Earth´s field with their heads, and that they use seamounts and oceanic islands as roadsigns on their migratory highway.
The film was critically acclaimed by the press, and audiences in Latin America and Europe are awaiting impatiently for it to arrive in their region.
More information, video and photos are available on the National Geographic website.
U.C.-Davis marine biologist Peter Klimley and crew bring in a scalloped hammerhead shark.
Dr. Peter Klimley and James Ketchum attach a tracking device to the hammerhead.
