Snapshot of a Stranding

Cape Cod sees more marine mammals wash ashore than anywhere else in the country. Now all that’s left is to figure out why.

Photo by Michael Cuoco

Marine mammal strandings have mystified humans for centuries. Last winter on Cape Cod, they continued to capture imaginations and national attention when a record 179 common dolphins stranded on Cape Cod Bay beaches from Sandy Neck to Wellfleet over 36 days between January 12 and February 16. The strandings continued later into the spring, marking 214 and counting this year, compared to an annual average of 38.

But no one is exactly sure what’s causing these numbers. “There’s so much we don’t know, and that’s kind of the hard part,” says Katie Moore, manager of the International Fund for Animal Welfare (IFAW) Marine Mammal Rescue and Research Team. “We see such a small percentage of time and life of these animals. Even when they’re seen we get a very short glimpse—a snapshot if you will.”

Experts believe a number of factors—from Cape Cod’s hooked shape, to the sediment size of Wellfleet mud, to tidal fluctuations, to dolphins’ social behavior—play a role in making the Cape the country’s top hot spot and the world’s third for mass marine mammal strandings.

“We look at it as a trap,” Moore says of the local coastline. “Our big hot spot is Wellfleet—it’s a hook within a hook so it’s a double trap.” Wellfleet’s very fine mud—volunteer first responder Tracy Plaut says you can sink to your hips in it—may be a culprit because it challenges the dolphins’ ability to echolocate. “They’re basically using sonar to navigate those areas,” Moore says. “It’s almost a way of seeing with sound.”

Also, Cape Cod Bay is home to extreme tidal fluctuations, some 11 feet and higher depending on the lunar cycle, conditions dolphins are not well acquainted with. “They’re used to being out in the open ocean and have no sense of tide,” Moore says. “And so the water just drops out from underneath them and they’re left high and dry in these spots.”

It’s one thing to talk about strandings in abstracts. It’s another to see them up close.

Photo by Michael Cuoco

From the Skaket Beach parking lot, it’s difficult to tell whether the animal out on the mud flats is in trouble or already dead. But as Michael Cuoco nears the dolphin, he sees it wiggling, as if trying to swim. When he carefully steps closer, approaching the front of the creature to prevent startling and stressing it further, he hears it breathe—a sudden whoosh is expelled from its blow hole. Cuoco calls the IFAW rescue team to report his location, and explain that this dolphin is alone and healthy.

A rescue team volunteer first responder for IFAW, Cuoco gets to work making the defenseless animal more comfortable to improve its chances of surviving its wayward swim along the Orleans shore. It’s a sunny, cold day in early March, but a brisk wind has kicked up sand that blows in the dolphin’s eyes. Cuoco pours water over them to clear them. He digs into the mud to give the pectoral flippers some room and allow the dolphin to breathe more easily, and he shoos away the scavenging sea gulls that try and peck at its eyes for an afternoon snack.

“I just kind of sat with it,” Cuoco recalls a few weeks later. “It was wonderful for me, but hard for the dolphin. It was just waiting for the next step.” When the rescue team arrives from Yarmouthport, members assess the animal’s health, looking for lesions, drawing blood, and monitoring breathing. Ultrasound will eventually reveal this dolphin—a female—is past the first trimester of her pregnancy. And when she is released off Scusset Beach in Sagamore later that night, hopes are high for her survival. But the following day she turns up dead on a Dennis beach after apparently re-stranding herself.

One researcher is developing a new explanation for this heartbreaking phenomenon. According to Moore, a member of the rescue team working on his master’s degree has found a correlation between the North Atlantic Oscillation Index, which shifts between positive and negative phases and mass stranding rates. The index affects sea surface temperature, prey distribution, and other environmental factors, and when it shifts into a negative phase and the water temperature drops, an increase in common dolphin strandings occurs the following year. A negative phase in 2011 preceded this year’s strandings. In 2013, the number of strandings of white-sided dolphins is expected to peak.

“So next year it will be interesting if this proves true, because this past year it shifted into a really negative phase,” says Moore. “I told the researcher he better get an A on this thesis because so far it’s proving true, which is interesting. But the key part is to tease out what factors are driving [this]. It’s a correlation; it’s not cause-and-effect.”

Moore hopes all the data she and her team have collected, including blood tests from live animals and necropsy results from those that didn’t survive, will shed light on what drove so many common dolphins inland last winter. The work will take months, and to help solve the mystery she’ll collaborate with other scientists, including those at the Provincetown Center for Coastal Studies, who were studying an early return of whales to Cape Cod Bay and higher water temperatures last winter. Preliminary results have shown no patterns or evidence of disease among the dolphins.

Marine mammal rescue and its accompanying data-sifting are critically important because the well-being of the dolphins is related to the health of the ocean and its impact on humans, Moore notes. What’s more, the ocean data her team gathers is shared with the National Oceanic and Atmospheric Administration, which is charged with making fishery management decisions.

Photo by Michael Cuoco

“It’s not just about the conservation and protection of marine mammals, but about the fish species that [NOAA is] tasked with managing as well,” she says. “It’s part of a bigger picture of ocean health and I think we’re one piece of the puzzle that’s really important.”

The work would not be possible without the army of some 350 trained volunteers, like Cuoco, who respond to strandings along the 700 miles of coastline from Plymouth, throughout the Cape and across to the Rhode Island border. Their efforts are invaluable and greatly contributed to the successful release of 76 percent of the live dolphins that stranded, Moore says.

“It’s not a pretty co-existence [between mammals and humans] going back many years,” says Plaut, a first responder from Wellfleet who previously ran the Nantucket Marine Mammal Stranding Team. “If we can do a little something now, I feel really good about that.”

The hours are long, and the work is taxing, back breaking and at times grueling. Some days, members of IFAW’s team are relieved by colleagues from marine organizations as far away as Virginia. But most days local people, including numerous volunteers, spend hours slogging through mud carrying stretchers bearing 250-pound dolphins. The day can start with a morning stranding bayside in Brewster and end after dark with a release in open waters off Herring Cove Beach in Provincetown.

But the reward can be big. On Valentine’s Day, 11 dolphins stranded near Chequessett Neck in Wellfleet and 10 survived. Rescuers decided to wait for the tide to come in and try to herd the survivors back out rather than move the dolphins on stretchers across mud to a trailer nearly a mile away, then set them free in outer waters. Volunteer Holly Kuhn, who is also a Bourne firefighter, was there that day and waded in with the creatures as the tide rolled in.

“Once they did start swimming, we had 10 dolphins swimming around us,” Kuhn recounts. “They were like little kids. They were more relaxed at that point. . .One of them started swimming off in the wrong direction and Katie started chasing him like a little kid.”

“The change in behavior was remarkable because the dolphins went from being stressed out and stuck in the mud, and as they became buoyant again they started letting out these chirps,” she says. “It was a complete change in behavior and mood.” It was a scene deserving of a snapshot.