OCEANPORT, N.J. (CBSNewYork) — Thousands of dead fish have been spotted belly up in Monmouth County waters, and environmental officials believe a bacteria is to blame.

Rotting fish can be found along the banks of the Shrewsbury River. The menhaden baitfish are critical in the marine food chain.

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“Without bunker fish, many of the fish that we’d like to eat, like striper or blue fish or whatever, wouldn’t exist,” said Jeff Tittle, with the Sierra Club.

Usually, large fish kills happen late in the summer when the water temperature rises and oxygen levels are low.

“It’s kind of troubling that it’s happened this early and to such a large extent,” Tittle told CBS2’s Meg Baker.

“This time around it seems to be here for a couple of weeks to a few weeks … It’s attributed to a vibrio bacteria infection,” said Swarna Muthukrishnan a staff scientist with Clean Ocean Action.

Environmental organizations like Clean Ocean Action and the Sierra Club are working with the state to investigate the bacteria, which attacks the fish’s organs and disorients it, causing it to swim in circles.

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Dead fish have also washed up along the Navesink and along the shores of the Raritan Bay.

Residents of one Oceanport neighborhood say the stench can be unbearable. Experts say they are right to be concerned about the health risks.

“People are going to want to go out, go kayaking and paddle boarding and playing fetch with their dog in the water, and they need to know that if you touch something that’s contaminated, like a menhaden that’s contaminated, and end up touching your eyes, you can have flu-like symptoms,” said Taylor McFarland, with the Sierra Club.

Large fish kills and algae blooms have been attributed to fertilizer run-off, sewer overflows, pet waste and more.

“Some of the ways that we can mitigate this is strengthening our storm water management rules … reducing fertilizers that have nitrogen in them,” McFarland said.

Environmentalists say this shows a planet out of balance. They are concerned if this is happening now, before summer, what will it be like in August?

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CBS2’s Meg Baker contributed to this report.

CBSNewYork Team