As crews clean up from this week’s massive fish kill along the Delaware Bay in lower Cape May County, New Jersey environmental officials now believe they have a clear idea of how it happened.

KYW’s David Madden reports that a second round of tests has confirmed the theory of experts regarding why tens of thousands of menhaden — or “peanut bunker” — washed up on Wednesday (see previous story).

Department of Environmental Protection spokesman Lawrence Hajna:

“The fish came close to shore for some reason. They encountered these very low oxygen conditions and there were just large numbers of them, and they consumed what oxygen was available and died.”

The warmer-than-usual temperatures were partly to blame for those low oxygen levels in the water.

Some of the dead fish are washing back into the bay with the tide. Those that aren’t are headed to the Cape May County landfill.