“We don’t know a lot about the reproductive system of this species,” says Hammerschlag, who has studied all kinds of sharks and has appeared on multiple episodes of the Discovery Channel’s Shark Week, an annual weeklong series of programming dedicated to all things sharks. “So it’s a bit of a holy grail in terms of understanding the biology of these animals—where they mate, where they gestate, where they give birth.”

Data from the ultrasounds, performed at sea on sharks lured and captured using bait traps, reveal that Tiger Beach is important for female tiger sharks of different life stages, and that a high proportion of the sharks were pregnant during winter months. Data also suggests that Tiger Beach “may function as a refuge habitat for females to reach maturity as well as a gestation ground where pregnant females benefit from calm, warm waters year round that help incubate the developing embryos and speed up gestation,” says Hammerschlag, noting that his research team also took blood samples for hormone analysis.