Four Dolphins Dead in 10 Days

In two cases, lacerations showed that fishing nets or lines could be the culprits
Members of the Riverhead Foundation for Marine Research and Preservation tried to rescue a bottlenose dolphin from Three Mile Harbor on Oct. 3, but it proved too sick to help. Dell Cullum

It has been a bad 10 days for dolphins on the South Fork. Two that washed ashore within two days on the ocean beaches in Napeague and Amagansett last week appear to have died after becoming entangled in fishing nets, according to officials, and another found struggling but alive in Three Mile Harbor early last week was later euthanized. A fourth washed up dead in East Hampton Village.

Workers at the East Hampton Marina spotted the dolphin in Three Mile Harbor at around 10 a.m. on Oct. 3. “One of our employees saw him swimming in the back making circles. He didn’t look good,” said William Plitt. The Riverhead Foundation for Marine Research and Preservation responded in an attempt to rescue it.

Chuck Bowman, the president of the foundation, said it was an offshore bottlenose dolphin — nearly 10 feet long. “It really shouldn’t have been there. Sometimes we’ll get smaller ones inshore,” he said, but one this big should never have made its way to the harbor. “It’s unusual,” Mr. Bowman said. “It usually means it’s compromised, disoriented, or sick.”

Using a sling-like contraption, the foundation’s team attempted to carry the dolphin back into deeper waters but it was too weak to float. It kept beaching itself, Mr. Bowman said. After several tries it became clear to rescuers that the dolphin needed to be taken out of the water. It was moved into a rescue van for transport. In the end, “the only real way to handle it was to have it euthanized,” Mr Bowman said.

A necropsy — usually done with tissue and blood samples — was performed on the dolphin. Results were pending, he said.

Then over the weekend, the Atlantic Marine Conservation Society performed necropsies on two deceased bottlenose dolphins that had washed ashore not far from each other in Amagansett. The first was reported on Friday afternoon around 2 p.m. at the end of Atlantic Avenue Beach, and the second was found Saturday morning at about 7 on the beach at Napeague Lane. Beachgoers discovered the dolphins, and the East Hampton Marine Patrol unit assisted. 

A team of society biologists and volunteers took the dolphin bodies to the East Hampton Recycling Center on Saturday. They performed the necropsies between 1 and 5:30 p.m., sending samples to a pathologist. The remains were disposed of at the recycling center. 

Both were female and sexually immature, between 5 and 13 years old, according to Rachel Bosworth, a spokes woman for the Atlantic Marine Conservation Society. The dolphin at Atlantic Avenue measured 6.9 feet long and weighed 300 pounds. The other dolphin was 6.3 feet and weighed 250 pounds. They both had lacerations on their skin “consistent with entanglement,” Ms. Bosworth said in a statement yesterday. “Line impressions on the right lateral tail stock of the smaller dolphin appear consistent with roping or line associated with netting.” The cases are being investigated by the National Oceanic and Atmospheric Administration’s Office of Law Enforcement. “At this time, it is too early to determine the actual cause of death as the investigation is ongoing,” she said. 

“Necropsies are an important research effort that allows us to better understand different marine mammal and sea turtle species,” said Rob DiGiovanni, the chief scientist with the conservation society. “Without understanding why animals are washing up dead we cannot make informed decisions on our impacts. For these necropsies, we believe they may be an offshore species considering the size of these bottlenose dolphins that washed up in relation to their age, as well as their body condition being free of marks commonly found on inshore dolphins.”

On Tuesday morning, a heavily-decayed dolphin carcass was found just west of the Main Beach pavilion in East Hampton Village. A responding police officer suspected it may have been the same one that had been discovered at Egypt Beach on Saturday. Beachgoers had dragged that dolphin back into the water before biologists were able to respond. 

Dolphins are protected under the Marine Mammal Protection Act. Under federal law, the public must stay a minimum of 50 yards away from them. Interaction can cause harm to people and the dolphins. Marine mammal sightings and strandings can be reported by calling 631-369-9829. Information can also be found at

Both the Riverhead Foundation and Atlantic Marine Conservation Society receive calls about strandings, with the foundation responding for live marine mammals and the conservation society responding for those that are deceased, according to Mr. Bowman. Both have different types of stranding agreements with NOAA. The A.M.C.S. also has a stranding agreement for large live whales and the Riverhead Foundation has the stranding agreement for live small whales, dolphins, seals, among others.

So far in 2017, the society has responded to reports of 109 marine mammals and sea turtles in New York State, Mr. DiGiovanni said.

Two dead bottlenose dolphins were also found in Southampton in early August. 

With four dolphins found dead or dying on East Hampton shores in just over a week, is there cause for concern? According to Mr. Bowman, no. He attributes the numbers to the fact that there were so many dolphins in the area this summer. Dolphins and whales came closer to shore to feed on menhaden. “I’ve never seen anything like it. There were acres of it,” Mr. Bowman said of the small fish, also called bunker. 

“If you’re going to have more animals, you’re going to have more dead animals. They do get sick, injured, die of old age. Everything has a life span,” he said. 

“Mortality events usually take place over a larger area. If there had been lots of dolphins washing up down in Maryland and then moving north,” he said, that would be another story. “This is not that unusual.”

In July, the Atlantic Marine Conservation Society completed its first marine mammal survey of the season offshore near the Shinnecock Inlet. It reported nine bottlenose dolphins were feeding in the area. The organization also collected 6.92 pounds of marine debris floating in the water, including 26 balloons. Marine debris is one of the leading causes of marine animal injuries and deaths.

With Reporting by Jackie Pape

A team from the Atlantic Marine Conservation Society, with help from East Hampton Town Marine Patrol, collected a dolphin found dead on Atlantic Avenue Beach in Amagansett on Saturday. Gabrielle L. McGee
Dell Cullum