Millions of dead fish recently turned up in Waackcaack Creek in Keansburg, New Jersey, according to an official with the state's Department of Environmental Protection (NJDEP).
The dead fish were all Atlantic menhaden, also known as bunker, NJDEP spokesman Lawrence Hajna told ABC News today. He said they likely died of suffocation.
The menhaden were probably chased by a predator species -- such as striped bass or blue fish -- into an inlet, Hajna said.
"From there, the water gets shallower and warmer, and the fish likely became tightly packed," he explained. "Hemmed in by the shoreline and predators, they used up the dissolved oxygen in the water and basically suffocated."
Nearby residents have been complaining about the awful stench coming from the rotting fish, ABC-owned station WABC in New York reported.
However, Hajna said the incident was "nothing extraordinary" and "part of a natural cycle."
"There's nothing much we can do except clean up, and that's what's been taking place," he said. "Local governments' public works crews have been scooping up the fish on the shorelines and also using a vacuum truck to take as many fish from the water they can."
Hajna added that some fish will naturally sink, decompose and become part of the creek's nutrient cycle.
"Other crabs and fish will eat them, and it's all just a part of nature," he said.