DOLPHINS

Stress Caused Deaths

Professor suggests different rescue protocol

By Russell Drumm

Doug Kuntz One of the 11 dolphins that died during rescue efforts in January was pulled from the waters of Northwest Creek.

(04/19/2007)    Preliminary findings point to stress rather than starvation as the cause of the dolphin deaths inside East Hampton’s Northwest Creek in January. The finding also indicate that those that succumbed were “young of the year.” Eleven died during a weeklong rescue effort.

    The arrival of common dolphins in Northwest Creek started out as an opportunity for thousands to watch, close up, the graceful mammals as they seemed to graze for fish, two by two, in the creek. As January grew cold, reaching 12 degrees on Jan. 16 when the dolphins were in the creek, fish became scarce, and it became clear that many of the 20 or so could not, or would not, go through the creek’s narrow channel into Northwest Harbor, where others were seen.

    The findings, to be discussed during a meeting next month of groups that respond to marine mammal strandings, throws into question existing aggressive rescue protocols. A resident of Northwest Woods, who is a New York University professor specializing in animal behavior, has suggested that a less stress inducing strategy should be used in the future.

    When, on Jan. 21, the last of the dead dolphins was carried away, at least some witnesses were beginning to wonder if the attempt to get them into open water — which involved using a line of boats to herd them along, with boaters beating on metal pipes, boat hulls, or anything else to make noise — had harmed the effort rather than helped.

    The rescue effort was the largest of its kind ever undertaken in the state. When it ended with 11 dead and 8 saved, officials declared it a success. And yet, necropsies performed on the dead animals during the intervening months, plus comments from pathologists from the University of Tennessee, suggest that it was not for lack of food that the animals died, as had been assumed. Instead, stress, and the inability of the pod’s younger animals to handle it, apparently caused the deaths, according to Kim Durham, a biologist with the Riverhead Foundation.

    In all, 11 federal, state, and local agencies and organizations took part. The National Marine Fisheries Service, using the strict guidelines of the Marine Mammal Protection Act, transferred its authority to the State Department of Environmental Conservation. It was aided by the Coast Guard, two divisions of the D.E.C., East Hampton’s Marine Patrol, and the Town Department of Natural Resources, the Riverhead Foundation for Marine Research and Preservation, the New England Aquarium, and Suffolk police. Kayakers paddled the creek to get up close and personal, as hundreds of visitors watched from shore.

    “It started out as a miraculous event and ended in tragedy,” said James Matthews, vice dean and professor of psychology and neurological science at New York University. The Northwest resident, who is active in the local environmental group Northwest Alliance, said he had been struck by the “paroxysm of kibitzing about what should or should not be done” that rescue attempts had spawned. Mr. Matthews said the condition of the creek had been “the primary question for the Northwest Alliance.”

    After meeting with Robert DiGiovanni Jr., the foundation’s director and senior biologist, last month, and becoming satisfied that the cause of the dolphins’ deaths was not something in Northwest Creek, Mr. Matthews said he joined the International Marine Mammal Trainers Association to discuss the efficacy of positive rewards, that is, training animals by rewarding them with food.

    Food as incentive is considered taboo in the world of marine mammal protection, however. “They have concerns. They don’t want the animals to make associations with people and good food. It disrupts the culture of the animals,” Mr. Matthews said.

    He suggested a technique called “auto shaping.” This would involve a sound source — “a robot that looks nothing like a boat” that would attract the dolphins. Once there they would find live fish. “You then move the robot [outside Northwest Creek into Northwest Harbor in this instance, for example] and keep going until their association with the creek is lost. Then you eliminate the sound.”

    “It’s introductory psychological stuff and should work in a couple hours. My research is on animal behavior and motivation. This is not something I’m unfamiliar with.” The Northwest resident presented his ideas to Mr. DiGiovanni. He said he predicted that those with the job of protecting marine mammals might worry about their forming associations, “even to the place itself, swim back in. But there are ways to minimize that chance. Cost benefit says give it a try.”

    On Monday, Ms. Durham, of the Riverhead Foundation, expanded on the studies that showed the dead dolphins were mostly “young of the year, smaller animals. At least one had a serious defect in the mouth, another had an injured flipper. They were less healthy. We were seeing natural selection firsthand. The ones left behind were young, they might have been animals that had just given birth,” Ms. Durham said.

    “The young animals trying to get out of the bottleneck didn’t have the experience. The ones that escaped were probably older, more experienced. . . . If there had been older dolphins in the mix, the stress would have tested them as well, Ms. Durham said. “I have no doubt the boats stressed them. We had to get permission from NOAA [the National Oceanic and Atmospheric Administration]. They were calling the shots. It’s why they were on the scene, not just the Riverhead Foundation. We knew there might be increased mortality,” Ms. Durham said.

    Ms. Durham explained that the hazing or herding of marine mammals using a line of boats and noise was the current federal protocol. “It’s what they use to get seals out of salmon traps in Alaska,” Ms. Durham said. Unfortunately, the method might affect common dolphins more than other marine mammals. 

    “Common dolphins’ stress tolerance is low on the scale. If it had been Risso’s dolphins or pilot whales, it might have been okay, but commons get stressed out,” Ms. Durham said. Feeding the dolphins, as some of those on hand had suggested, would probably not have worked because dolphins don’t eat dead fish. Using nets to push the animals toward the inlet might have entangled them.

    The question of rescue methods will be debated at the meeting from May 1 through 4 in Atlantic City, when Mr. DiGiovanni presents a paper on the event to organizations responsible for responding to strandings along the East Coast.