Officials from the New Jersey Department of Environmental Protection (DEP) believe that a lack of oxygen may be behind a massive fish kill in the Shark River this week. According to CBS New York, tens of thousands of fish were found floating on the surface of the river on Monday. The vast majority of the fish affected were menhaden, but observers also spotted flounder, puffers, and the occasional striped bass. Visitors to the docks in Belmar were greeted by a host of smelly, decaying fish.
“It is very alarming when we see something like this,” Belmar Mayor Matt Doherty told WCBS 880. “And right now, we’re cleaning up what’s here, and we’re still trying to find out what the source of this fish kill is.”
The DEP stated that the fish kill may be a result of simply too many fish in too small of a space. Experts initially believed that heavy rains may be to blame for the disaster, but it is now suspected that a large school of fish entered the Shark River Inlet and consumed all the oxygen. Oxygen deprivation is one of the most common causes of fish kills, especially after harsh winters. Experts say that menhaden can breed in large numbers and tend to congregate when chased by predators, so it may be likely that the fish found themselves trapped in shallow parts of the inlet where they suffocated one another. An algae bloom can also cause a rapid loss of oxygen.
However, the Asbury Park Press reports that samples taken from the river afterwards found an acceptable oxygen level. County workers found that water samples taken from a Belmar beach held an oxygen level of about seven milligrams per liter.
“Most fish do fine at 5 milligrams per liter,” said Monmouth County Health Department coordinator Michael Meddis.
Cleanup crews are now removing dead fish from the water, although that task is made more difficult by the sinking menhaden. Some anglers have used the opportunity to collect and freeze the valuable bait fish for future expeditions. DEP officials have also gathered samples and will be waiting on test results before making an official determination on what caused the fish kill.
Local anglers and fishermen speak up about the fish kill in the video below: