Every time something with a prominent dorsal fin slices through the water off a Massachusetts beach, a question races through everyone’s mind: What the heck was that?
Now, officials at the Cape Cod National Seashore and the Massachusetts Division of Marine Fisheries are hoping to provide some answers, by compiling a manual to help lifeguards and beachgoers identify what they have seen.
The manual is only in the planning stages but officials hope to complete it in a few weeks.
Shark concerns have been growing in recent years, with an increased number of great white shark sightings, particularly in areas along the Cape frequented by seals, a favorite food for some sharks.
Last Monday, a Colorado man — who had been swimming with his son off Ballston Beach in Truro — needed dozens of stitches after being bitten in the legs by what officials believe was a great white shark. The national seashore has been contacting other national parks across the country for help with the manual, particularly the Golden Gate National Recreation Area in California, which often deals with great white sharks in its waters, said Leslie Reynolds, the seashore’s chief ranger.
The manual will include multiple marine animals, helping people to distinguish great white sharks from other harmless animals that people can mistake them for, including basking sharks, sunfish, dolphins, whales, and even birds, Reynolds said.
The officials do not expect the manual to turn into an all-encompassing encyclopedia, but a good reference for what people may encounter in New England waters.
Along with the reference manual, there will be a questionnaire for the public to fill out after shark sightings, said Reynolds. The national seashore is also finalizing its manual for response to shark or other animal attacks, she said.
SARAH N. MATTERO