Long Islanders thought winter had arrived early when they walked near the Shinnecock Canal in Hampton Bays, New York, on Monday.

The water looked like it was covered in a thick sheet of ice, but upon closer examination, residents could see it was actually thousands of silver bunker fish wiggling on top of each other, struggling to survive.

Dozens of people posted pictures and videos of the unusual sight on Facebook.

“Strange phenomenon. Cause of man or nature?” local resident Gustavo Zuluaga Buritica asked.

“Wow never seen anything like it!” Long Islander Eric Reilly commented.

As videos of the rare sight go viral, people are now looking for answers.

The New York State Department of Environmental Conservation told CBS News on Tuesday that they are monitoring the incident.

“No additional fish kills have been reported overnight or today,” said Erica Ringewald, the department’s media relations director. “Some dead bunker are floating in the Shinnecock Bay but most are believed to have sunk to the bottom.”

The town of Southampton has been cleaning up the dead fish on the beaches and DEC Marine Resources is arranging for aerial overflights to track the movement of the dead fish, Ringewald explained.

“Southampton worked with the County Department of Public Works to open and close the canal to keep the oxygen levels up while allowing some fish to escape,” she said…..More Here