When Islanders think about beach erosion, grey seals may not be what comes to mind as a leading cause. But seals are top of mind for Crocker Snow.

As gray seal pupping season comes to an end off the coast of Massachusetts and Maine, scientists are finishing a study.

Crocker Snow Jr. remembers vividly the first time he set foot on Muskeget island. The 250-acre stretch of sand and scrub brush forms the westernmost tip of Nantucket.

The sandy shoals of Muskeget Island are familiar to boaters and fishermen who ply the waters between Nantucket and Martha’s Vineyard, but the island’s rich ecological history may be less well known.

It’s been 35 years since the movie Jaws forever linked great white shark attacks and Martha’s Vineyard in the popular imagination of the world, yet in all that time no one has ever been attacked.

Then, long after all thought it was safe to go back in the water, along came the U.S. Coast Guard with last week’s holiday boating advice, headed “Shark Advisory” and warning swimmers, kayakers and small boaters of the danger of great white sharks.