A "major" fish kill was found in the waters in the Shark River Inlet in Belmar Tueasday.
The state Department of Environmental Protection has taken samples and "we are cleaning up our area," said Mayor Matt Doherty.
"Very concerning," he wrote on his Twitter page.
Initial indications are that fish kill was due to low oxygen in the water. "We are still waiting for results of testing on dead fish," Doherty said.