A rare longfin mako shark "phoned home" with some incredible and unexpected details about its five-month journey in the Gulf of Mexico and the Atlantic Ocean, scientists announced Thursday.
The longfin mako shark, one of only a handful ever equipped with a satellite tag, revealed it had covered nearly 5,500 miles—averaging about 36.5 miles a day—and followed an almost identical route as a previously tagged longfin mako shark.
It also spent the majority of its time in depths less than 1,640 feet, remaining deeper during the day than at night. At one point it swam down 5,748 feet, more than a mile deep.
In the first expedition to satellite-tag sharks in Cuban waters, a team of scientists from the U.S. and Cuba successfully put a satellite tag in the longfin mako shark on February 14 off Cojimar in northern Cuba.
Five months later, on July 15, as it was programmed to do, the tag separated from the shark and popped to the surface 125 miles east of the mouth of Chesapeake Bay where it began sending archived data to Mote scientists via satellite.
"The amazing thing is this longfin mako’s tag popped up in nearly the same exact location as another one we tagged in the northeastern portion of the U.S. Gulf of Mexico a few years ago," said John Tyminski, an associate researcher for Mote Marine Laboratory.
"The movement patterns of the two sharks are remarkably similar: both sharks were in the eastern Gulf in April/May, showed comparable movements through the Straits of Florida, and ended in a similar area off Chesapeake Bay in July.
"Both tags came off during the month of July and both sharks were mature males. Clearly there’s something in that location that’s attracting mature males in summer."
Mating, feeding or simply passing through were possibilities given. Scientists are also wondering why the longfin mako shark dove so deep, speculating that it might have been searching for food.
"At that depth [5,748 feet] the shark is dealing with extreme cold, close to freezing," said Dr. Robert Hueter, director of the Center for Shark Research at Mote.
"The data from this tag will help us understand why these sharks are diving so deep and how they are dealing with such cold temperatures."
Unlike the shortfin mako shark, almost nothing is known about the longfin mako shark, so the new data will help shed light on the species, which is classified as vulnerable by the IUCN.
"The fact that these sharks go back and forth among the waters of multiple nations—in this case, Cuba, the United States, the Bahamas and Mexico—shows the importance of coordinating our fisheries sustainability and conservation efforts on a multilateral, even global, scale," Hueter said. "Clearly it is important for the U.S. and Cuba to work together to protect vulnerable marine resources like these rare and depleted species of sharks."
An update on the tagged longfin mako shark will be aired on Discovery at 7 p.m. on August 30 during Shweekend.