After a steady tide of dead bunker washing ashore on Flanders Bay beaches in the Town of Riverhead over the past few days — a phenomenon marine scientists at Stony Brook University say is linked to a lethal algal bloom — the dead baitfish are now washing ashore in Southold Town.
Bunker, which seasonally migrate into the Peconic Estuary and its tributaries to spawn, can be seen today floating dead by the dozen in West Creek in Cutchogue. Is it a harbinger of things to come? Will Peconic Bay beaches soon be covered with tens of thousands of dead bunker the way Flanders Bay beaches on both forks have been since Thursday night?
No one knows if the phenomenon is tracking east.
Dr. Christopher Gobler of the Long Island Coastal Conservation Research Alliance and a research professor at Stony Brook University’s School of Marine and Atmospheric Sciences says his team of researchers has not been sampling the waters of the Peconic Bay. “Our sampling was confined to the Peconic River region,” he said this afternoon.
Southold Trustees did not get any calls reporting bunker kills as of Friday afternoon, Trustees president John Bredemeyer said Sunday afternoon. “But with fish like bunker, that have to keep moving to get sufficient oxygen, a kill can happen in as little as two to three minutes,” said Bredemeyer, who worked for 25 years as a Peconic Estuary researcher in the county health department’s office of ecology.
Gobler says a “massive mahogany tide” — the algae Prorocetrum — is blooming in the Peconic Estuary, in Flanders Bay in particular. The bloom began in early May, he said. Levels of Prorocentrum in water samples tested by researchers are “some of the highest we’ve seen in the region,” Gobler said.
“Prorocetrum is common in tributaries this time of year,” Gobler noted. He blames the algal bloom for “driving the oxygen levels down, which is leading to anoxia and the fish kill” being seen in Flanders Bay, he said.
“Dissolved oxygen levels dropped to zero for an extended period” Thursday night, Gobler said.
“The overgrowth of other types of algae can also lead to low oxygen,” he said.
Algal blooms are promoted by excessive nitrogen loading, scientists say. The nitrogen comes from numerous sources, including stormwater runoff, sewage treatment plants and septic systems. It also comes from historical sources, such as duck farm sediment, Bredemeyer said.
“When I first heard of the bunker die-off, Prorocetrum was the first thing that came to mind,” he said.
Bunker kills are not infrequent in the estuary. Fishermen and longtime residents recall significant die-offs which typically resulted from bluefish chasing large schools of bunker up into dead-end creeks. The huge numbers of trapped bunker in the creeks’ upper regions overwhelm the creek’s ability to sustain them and they suffocate, sometimes by the thousands.
The bunker kill in recent days in western portions of the estuary has been different. Instead of manifesting in creeks where the fish have no outlet, the dead bunker are washing ashore on bay beaches. Creeks have not seen any major accumulations of dead bunker so far.
The shores of Indian Island County Park are layered thick with rotting dead bunker, drawing flies and raising public health concerns. The stench is overpowering.
“The county’s going to have to go in there with some kind of heavy equipment and get them off the beaches,” Suffolk County Legislator Al Krupski said this afternoon. “We can’t leave them there like that.” Krupski said he would contact Suffolk Parks Commissioner Greg Dawson about it first thing Monday morning.
“We’ll see if this is something making its way east,” said Krupski as he inspected the shoreline of West Creek this afternoon.
People on the bay beach in Mattituck this afternoon said there were dozens of dead bunker on the shore yesterday. But today, the dead fish were gone — apparently washed out with the tide.
“Bunker are filter feeders, like shellfish, so it makes sense an algal bloom would affect them first,” said Krupski, who served nearly 20 years as a Southold Trustee. “It makes you wonder what else is going on in the waters out there,” he said this afternoon at West Creek, gesturing toward the bay.