NOAA: Big groups of basking sharks off Long Island in the past

There’s no known assemblage of sharks off Long Island’s shores. But, they’ve been there.

Three decades of research that concluded five years ago shows large groups of basking sharks have congregated along the Northeast coast, including Long Island, according to researchers from the Northeast Fisheries Science Center, under the umbrella of the National Oceanic and Atmospheric Administration. The research was reported in a study in the Journal of Fish Biology earlier this month.

Still, shark fearers need not fret. Basking sharks are the world’s second-largest fish, growing to 32 feet in length, but they’re considered harmless.

No large groupings have been spotted so far this year, with aerial surveys by the Northeast Fisheries Science Center team having resumed March 20, following a winter hiatus, said Shelley Dawicki, communications specialist.

Such surveys stretch from the Gulf of Maine down to Long Island Sound, she said.

Basking sharks’ search for zooplankton and, shall we say, intimate companionship could be behind the large aggregations. Ten such large groups ranging from 30 to close to 1,400 basking sharks have been observed through aerial surveys from 1980 to 2013 in waters from Nova Scotia to Long Island, NOAA said Thursday in a news release.

These slow-moving creatures “are considered passive and no danger to humans other than that posed by their large size and rough skin.”

Sightings of the lone basking shark are common, NOAA says, but observations of such large groups is “relatively rare.” The groupings were observed “in summer and fall when sea surface temperatures ranged between 55 and 75 degrees F,” with the largest assemblage — spotted in 2013 in waters off southern New England — showing “a high concentration of zooplankton prey” in the picture.

Researchers have no solid data on just why these sharks cluster together at some times, though NOAA says, “it is thought to be related to feeding, socializing, and/or courtship, given behaviors in other shark species.”