Some sharks return to the same sites to breed for decades

Some species of shark return to the same breeding grounds for decades at a time, and live longer than previously thought, scientists studying the animals off Florida say.

Scientists with the New England Aquarium found that nurse sharks returned to the waters off the Dry Tortugas, 70 miles (113 kilometers) from Key West, to mate for up to 28 years. They also found that the sharks' life span appears to extend at least into their 40s, rather than about 24 years as previously believed.

The researchers published their findings in October in the journal PLOS ONE as part of the world's longest running study of shark mating behavior. The research sheds new light on the way sharks breed and the role their environments play in their reproduction, said Nick Whitney, a senior scientist with the aquarium and a co-author of the study.

“This is the first example that has shown long-term use of a mating ground,” Whitney said. “To observe natural shark behavior in the wild is incredibly rare to begin with and to observe mating behavior is really unusual.”