RIVERHEAD, N.Y. (CBSNewYork) — Thousands and thousands of dead, smelly bunker fish are floating in the Peconic River and washing up on the banks of a marina in Riverhead.

As WCBS 880 Long Island Bureau Chief Mike Xirinachs reported, it’s the second massive fish kill in the area in as many weeks.

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Experts blame low oxygen levels for the kill, but what exactly is causing the problem remains a mystery.

Boat owners can only guess.

“Obviously, the brown tide, whether it is natural or not, there’s the concept and thought that the pesticides from the golf course over here (is to blame),” said boat owner Wayne.

Others point the finger at a nearby sewage plant.

Meanwhile, town officials are now dealing with the cleanup.

“It’s disgusting,” Wayne said. ” … It’s not a good thing. The bottom line is how they’re going to get cleaned out of here. That has yet to be seen. It’s a hazard.”

The town supervisor is working on the cleanup effort with the Department of Environmental Conservation, the Water Authority and Coast Guard.

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“There’s a confluence of events that have caused this problem,” said Riverhead Town Supervisor Sean Walter. “The biggest issue is that we have too many bunker and too many bluefish.”

CBS2’s Jennifer McLogan boated down the Peconic River where the predator bluefish could still be seen chasing bait fish bunker into shallow waters, where they can’t breathe.

Winds, tides, and water temperature also contribute to the fish getting trapped. Plenty of blue-green algae respires at night, adding to the depletion of what little oxygen remains, McLogan reported.

Watch: Could Weather Be Contributing To Dead Fish In Peconic River? 

“The oxygen levels in the Peconic River went to zero,” said Stony Brook marine scientist Chris Gobler.

Gobler said brown tide is also creating high nitrogen levels and notes that about 90 percent of homes in and around the river have septic systems.

The town is in the process of upgrading its sewage treatment facility.

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The plan is to pay fishermen .32 cents a pound to net the fish and bring them to the dock, where they will be scooped into trucks and hauled to the landfill for burial.