Hundreds of bunker, their mouths yawning open as they gape for oxygenated water and to clean their gills, were filmed swimming in the Peconic River Wednesday.
It’s a sign that a harmful algal bloom, known as mahogany tide, could soon cause another large fish kill in the river.
The video was shot underwater off the banks of the Peconic River at about 5:30 p.m. Wednesday by marine biologist Chris Paparo.
“I was down there this morning and there was even more fish than there was yesterday,” Mr. Paparo said Thursday morning.
And although bunker, also known as menhaden, do swim with their mouths open while feeding, Paparo said that is not what is happening in the above video.
Marine researchers have been tracking a bloom of the same algae that caused a massive die-off in the river last May, according to an in-depth report published Wednesday on riverheadlocal.com.
“They get so dense that they cloud the water,” Mr. Paparo said of the blooms. “It’s like an orangey, rusty brown.”
Predator fish, like bluefish and striped bass, frequently chase bunker into shallow, low oxygen waters sometimes causing die-offs around this time of year. But last year scientists reported one of the biggest fish kills ever in the region following an algal bloom, something they said in a February report could become the norm.
On Thursday, the Riverhead Town Board discussed a plan to remove bunker fish from the Peconic Bay in hopes of preventing another large fish kill. The town and the state DEC would pay fishermen four cents a pound to remove the bunker, under the proposal.
Fishermen hired by the DEC have already removed over 150,000 pounds of bunker fish since Monday, Town Supervisor Sean Walter said.
Nitrogen is the key culprit in a fish kill. The nutrient, which can come from septic tanks, cesspools or fertilizers, gets washed into the water supply by rain.
The nitrogen then gets eaten by blooms of algae which grow bigger and suck oxygen out of the water at night.
Algae, like all plants, use oxygen when the sun goes and down and emit CO2.
Fish also need oxygenated water to survive and when the oxygen content reaches dangerously low levels, they die.