It’s not just great white sharks cruising around our local waters.
Hammerhead sharks were recently spotted off the Bay State coast, according to a leading shark researcher who said it was the first reported hammerhead sightings of the season.
Multiple hammerheads were seen in Buzzards Bay off Cuttyhunk Island, according to John Chisholm, adjunct scientist at the New England Aquarium. That island in the Elizabeth Islands chain is to the west of Martha’s Vineyard.
This is the time of year when hammerhead sharks are first spotted on the south side of the Vineyard or Nantucket, Chisholm added.
“When the water gets really warm, you can even get hammerhead sightings near New Hampshire and Maine,” he said.
The hammerhead sightings could be a sign of things to come for other warm-water sharks.
“As the water keeps warming, I anticipate that warm-water species will be showing up in greater numbers,” Chisholm said.
Those species include blacktip, spinner and bull sharks.
A bull shark was spotted off a Long Island beach last summer.
“If the water gets warm enough up here, I would expect to see them,” Chisholm said.
He added that some local fishermen have claimed that they caught a bull shark, but he never obtained photographic confirmation.
Bull sharks are robust and powerful, often called the “pit bulls of the sea,” and rank third in unprovoked bites due to their tendency to pursue prey larger than themselves. (Credit: Cineflix)
Bull sharks have been slowly increasing their range up the East Coast in recent years because of the climbing water temps. In addition to the sea, bull sharks also enjoy shallow warm estuaries and bays, and they can tolerate fresh water.
Tens of thousands of seals along Cape Cod have attracted great white sharks in recent years. While bull sharks prefer to eat fish and rays, they’re capable of eating seals.
Meanwhile, tiger sharks have been spotted sporadically off the Islands in recent seasons. Last year, a large tiger shark washed up on a Nantucket beach. The shark was swept out to sea at Tom Nevers Beach before the apex predator could be secured by beachgoers.
Recent research has found that tiger sharks are migrating farther north each year because of warmer oceans. While waters off the Northeast have historically been too cold for tiger sharks, temps have warmed significantly in recent years and are now suitable for tiger sharks, according to researchers.
The shark scientists from the University of Miami warned that tiger sharks moving north could lead to more interactions between sharks and humans.
During the last decade — when ocean temperatures were the warmest on record — for every one-degree Celsius increase in water temps above average, tiger shark migrations extended farther poleward by roughly 250 miles.
Originally Published: July 15, 2025 at 3:06 PM EDT