Katie Gilbert of Marine Mammals of Maine takes samples from a dead dolphin on a Phippsburg beach. Photo courtesy of Marine Mammals of Maine 

Four dolphins and porpoises have been found dead on Maine beaches in recent months, but marine mammal experts say that doesn’t ring alarm bells.

Most recently, the body of a short-beaked common dolphin, one of two types of dolphins found in Maine waters, was reported on March 21 near Small Point Beach in Phippsburg.

Lynda Doughty, Marine Mammals of Maine founding executive director, said the cause of death isn’t known, but she “didn’t see any evidence of anything that was worrisome.”

Doughty said the animal likely died in the ocean from injury or illness then washed ashore with the tide.

Marine Mammals of Maine is a Brunswick-based nonprofit dedicated to marine mammal and sea turtle response, rescue, care, research and education. The organization responds to roughly 300 calls of stranded marine animals each year, about 10-20% of which are dolphin, whale and porpoise calls.

While the dolphin in Phippsburg showed no obvious signs of injury or illness, Doughty’s team took samples from the animal to test for diseases. Even if she never knows how the dolphin died, Doughty said it’s important to monitor the species when possible.

“We test for viruses because we want to monitor them in case something was to happen,” she said. “Sometimes the animals just don’t make it, but we still want to capture the event to keep an eye on things.”

Another dead short-beaked common dolphin was reported in late December, according to Doughty, but it was too decomposed to determine a cause of death.

Two dead harbor porpoises were found on Cape Elizabeth beaches in August and November. Both animals were scavenged too heavily for Doughty’s team to glean any information, but she said there are no obvious connections between the four deaths.

Rosemary Seton, marine mammal stranding coordinator at College of the Atlantic, said marine mammals can experience “unusual mortality events” — when one illness wipes out many animals in a singular species, usually as a way to control the population. The most recent morality event happened in late summer 2018 when a form of distemper surged through harbor seals in Maine, according to Seton.

Around the same time, dolphins around Florida experienced a similar mass mortality event, but it didn’t spread up the east coast, Doughty said.

About 15% of Marine Mammals of Maine’s 300 calls turn out to be healthy animals, usually seals, which are the most commonly seen marine mammal in Maine, according to the Department of Marine Resources.

If someone sees a marine mammal that appears to be in distress, both Doughty and Seton said it’s important to call for help instead of trying to help the animal yourself. Seals, whales, dolphins and porpoises are federally protected, and trying to help the animal back to sea could injure the animal.

“If you do see a dolphin in-shore, there’s probably something wrong,” said Seton. “If we see a dolphin by itself, that’s a red flag because dolphins are usually found in more tight-knit social groups. If that animal is inshore or stranded, it’s there for a reason.”