Numerous reports of dead and dying bunker fish washing up on Long Island beaches in recent weeks have prompted state officials to collect samples for study.
Distressed fish — possibly sickened by low water oxygen levels or rapid changes in temperature — have been spotted from the lower Hudson River near Peekskill to Staten Island and beaches on Long Island's North Shore and the East End, officials said.
The state Department of Environmental Conservation has sent fish samples and water quality data to Stony Brook University's Marine Animal Disease Laboratory and Cornell University for examination, officials said.
Bunker, or Atlantic menhaden, are a popular bait fish that number in the billions from Nova Scotia to Florida. Hundreds of millions of the fish are harvested annually for fish oil, fertilizer and fishmeal, authorities have said.
Die-offs of bunker are not considered unusual. The fish swim in large schools that leave them vulnerable to changes in their environment, such as temperature fluctuations and insufficient sources of dissolved oxygen. It is common for large die-offs to occur in summer, officials have said.
A 2015 die-off that killed hundreds of thousands of bunker in the Peconic River was attributed to low dissolved oxygen levels and toxic algae, officials said.
Christopher Gobler, a professor at Stony Brook University's School of Marine and Atmospheric Sciences, said it's too soon to determine the cause of the recent fish kill. He said he hopes to reach a conclusion early next year.
But he said unusually warm water followed by a steep temperature drop could be one of several possible explanations. The Long Island Sound this summer, he said, was about 5 degrees warmer than in past years.
"The fact that the fish are sticking around is unusual," Gobler said. "Long Island Sound got extremely warm this summer. ... It got warmer and stayed warmer longer than it normally would."
Bunker should be migrating to Florida this time of year, Gobler said, but if their migration patterns are based on water temperature, "they were getting all the wrong signals come this fall."
Carole Trottere of Old Field said larger than normal numbers of dead and dying fish began washing up more than a month ago on beaches along Smithtown Bay. She said she had never seen so many sickened fish there before.
"They, almost like salmon, beach themselves and die. It’s really sad," said Trottere, who works in public relations. "The seagulls are having a ball. They’re all getting fat."
Suffolk County Legis. Kara Hahn (D-Setauket) said she had noticed a "really odd" number of dead fish during walks near West Meadow Beach in Stony Brook.
"I counted 100 or more. I stopped counting at 100," Hahn said. "You’d see 10 in an area and you go 20 feet and you see another five."