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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

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.

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