Over the past decade, the waters around Cape Cod have become host to one of the densest seasonal concentrations of adult white sharks in the world. Acoustic tagging data suggest the animals trickle into the region during lengthening days in May, increase in abundance throughout summer, peak in October and mostly depart by Thanksgiving.

To conservationists, the annual returns are a success story, but the phenomenon carries unusual public-safety implications.

Unlike many places where adult white sharks congregate, which tend to be remote islands, the sharks’ summer residency in New England overlaps with tourist season at one of the Northeast’s most-coveted recreational areas.

What will it take to keep people safe?

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