Thousands of dead fish have been found washed up along the shorelines of bays on northern Long Island and its East End.

The dying and dead bunker fish were noticed by residents early Saturday morning in Manhasset Bay.

The town of North Hempstead was notified of the issue on Friday. Officials say the state Department of Environmental Conservation was immediately called to assess the situation. They are now are awaiting the results from the investigation.

News 12 reached out to the DEC for comment, but it has not yet heard back.

Meanwhile, tens of thousands of dead fish washed up where the Peconic River meets Flanders Bay. A professor of marine science at Stony Brook University says that high levels of nitrogen in the water cause what is known as "mahogany tide."

The professor says that oxygen levels in the water were zero on Friday, which caused the bunker fish to suffocate. As previously reported, the high levels of nitrogen in the region are caused by human wastewater and fertilizer.