Keansburg Fish Kill Likely Due To Low Oxygen Levels, Officials Say

KEANSBURG, NJ — Low dissolved oxygen levels in stagnant water appear to be the cause of thousands of small dead fish washing up along creek beaches in Keansburg, according to state officials.

Photos of the dead fish — juvenile menhaden, more commonly known as peanut bunker — have been circulating on social media, particularly as the fish began washing up on beaches. The largest portion of the die-off is being seen in Waackaack Creek, a tidal creek off Raritan Bay.

Bob Considine, a spokesman for the state Department of Environmental Protection, said DEP conservation officers and the agency's emergency response have been on the scene of the fish kill, in tidal waters off Raritan Bay, for the past few days.

"We believe at this point that the die off is due to dissolved oxygen levels in the water," Considine said. He said the peanut bunker, which average 4 to 5 inches long, were likely fleeing from larger predators, including bluefish or skates, and because the fish became so bunched up they depleted the dissolved oxygen in the water.

Read more about bunker and this phenomenon in this 2014 article posted to the Patch.

Similar die-offs have happened in previous years. In 2010, a massive die-off of peanut bunker in Cape May County garnered the attention of New York media outlets.

The NY/NJ Baykeeper posted photos on Facebook on Friday of dead peanut bunker floating in the water and said the die-off was seen in Raritan Bay, including Leonardo Marina, Thornes Creek and Natco Lake.

Sandra Meola, a spokeswoman for the organization, an advocate for clean water and the Raritan Bay, said they are testing the water for dissolved oxygen levels Tuesday and hoped to have results later in the afternoon. She also said the die-offs are not uncommon when the water temperatures in the bay and the tidal creeks reach their warmest, typically in August.

Meola said the cause is definitely not toxic algae.

Considine said the peak of this recent wash-up was Saturday, and while many of the fish had been washed back into the water, they're washing up again with the incoming tides.

Dead peanut bunker washed up on Keansburg Beach on Monday. Photo courtesy of NY/NJ Baykeeper