BOSTON — More seals mean more great white sharks.
That's how marine scientists explain the growing number of great white sightings off the Massachusetts coast in recent years, and part of why they think a shark attacked a swimmer in Truro Monday: it thought he was a seal.
So it's not that shark populations in the area are rising; it's that sharks are increasingly congregating near one of their favorite food sources, gray seals, which have become more plentiful in local waters over the decades.
WBUR's All Things Considered host Sacha Pfeiffer spoke about this changing ocean dynamic with Dr. John Mandelman, a research scientist at the New England Aquarium whose specialties include sharks.
This program aired on August 1, 2012.