With plenty of room, food and no predators (other than humans behind a gun or steering wheel), deer, skunks, squirrels, rabbits and raccoons on the Vineyard enjoy a level of sanctuary to be envied by their mainland counterparts, allowing their populations to grow to considerable size.

Is it the same for otters? These elusive, semiaquatic mammals, largely nocturnal and less visible to the casual observer, present more of a mystery. Wildlife biologists Luanne Johnson, of West Tisbury, and Liz Baldwin, of Oak Bluffs, have begun research on otters — to determine not only how many otters are here but what role they may play in protecting the water quality of the great ponds.

“They are the top carnivores at our great ponds,” Ms. Johnson said, noting that otters can be found just about anywhere on the Island, near freshwater and in coastal ponds, fresh or salt. Being at the top of the coastal environment food chain, their health is dependent on the health of the ponds.

The two scientists’ research appears to be unprecedented; Ms. Johnson said nearly all the research done on otters is either about inland otters or those on the West Coast.

Ms. Johnson is already well known on the Vineyard for her doctorate work at Antioch University on the behavior and habits of coastal skunks.

Ms. Baldwin, a 1999 regional high school graduate now studying for an environmental science master’s degree at Antioch, marvels at the otters here: “There are so many spots where they hang out. There are places where you would think they would hang out and they don’t.”

Ms. Baldwin said as far as she can tell there has been no science on river otters living on the coast in the Northeast. “I found two papers on river otters in Massachusetts,” she said, and both referred to animals living inland.

Another appealing aspect for this research, she said, is that the Vineyard otter population is isolated. “We are an Island and that makes our population even more different. Islands are great petri dishes,” she said.

The research is bring funded by grants of $5,000 each from the Edey Foundation and the Dr. William and Nan Harris Family Foundation, grants administered by the Sheriff’s Meadow Foundation. They also received help from every major Island conservation group.

“The EPA didn’t give money,” Ms. Johnson said, “but they gave us high marks for the project,” particularly for the involvement of the community, which includes school children.

This week, students in David Faber’s science class went to a site on the shore of Edgartown Pond to collect otter scat.Mr. Faber was one of the Vineyarders who wrote in support of the project during the grant-writing process last winter.

“This is perfect science for these kids,” Mr. Faber said, standing in knee-high boots on the shore of the pond. He points out that the project is easily explained, and the students are collecting and evaluating the data themselves.

Once the students finish collecting samples, one of them sprinkles glitter on the feces. The reason, Mr. Faber says, is so that the next time the students return to the site, they can better distinguish the fresh specimens from specimens already documented.

From the work being done, Ms. Johnson said, they’ll be able to gain a better sense of the Island’s otter population, where the otters are going, and what they are eating. So far, the researchers are finding the remains of perch, striped bass, shellfish and a lot of small fish. “We want to know whether they eat green crabs,” she said.

They have learned already that otters spend a lot of time hunting and wandering the Island’s coastal ponds, and will also wander more than a mile inland to visit a freshwater pond. Otters are twilight mammals, preferring to move and fish either at dawn or dusk, though Ms. Johnson said she’s seen them hunting as late as 11 a.m.

Ms. Johnson said researchers have uncovered what appear to be ancient otter trails. The animals are creatures of habit, and often walk the same trails as they move about the Vineyard.

This first phase of the research, the collection and inspection of scat in pursuit of a general understanding of the otter population and their diet, will be done by March. The next phase involves laboratory DNA analysis that should present a much more specific picture of the individual otters that make up the population, their behaviors and their social networks.

Specifically, the laboratory data should reveal how animals in different locations are related: Island otters will be compared to otters on the Cape, Nantucket and Naushon; and will hopefully shed light on the social behaviors of Island otters. For example, how do otters on the east side of Edgartown Great Pond relate with otters on the west side? How do Edgartown otters relate to those in West Tisbury.

This second phase of the project, however, is much more expensive. Ms. Johnson estimates the cost at $15,000, but mentions that fundraising is already underway. Each DNA sample analysis costs $160. She notes that otters are difficult to evaluate on the basis of appearance for the simple reason that they all look alike. “Whales, skunks and raccoons have markings on their tail and body which makes it easier to distinguish one animal from another,” Ms. Johnson said. The laboratory work will enable the identification of specific individuals within the population.

Involving the Vineyard’s school children is a major component of the study. Ms. Johnson learned community-based research and wildlife restoration while working with Tom Chase on the Trustees of Reservations’ Sandplain Restoration Project. Ms. Johnson believes this approach can have a long-term, positive impact on the community.

Gus Ben David of Edgartown, a former director of the Massachusetts Audubon Society’s Felix Neck Wildlife Sanctuary, used to care for a young otter called Scuba Joe in the 1970s. He had high praise the project.

“He is a wolf in sheep’s clothing,” Mr. Ben David said of the otter. “Through his antics, running and sliding across the snow, people interpret it as an animal at play. They look happy-go-lucky. In reality, they are giant weasels and capable predators. Although his diet consists primarily of various fish, this animal is a very capable one. When fish stocks are low, they can turn to capturing small mammals and birds.

“They are magnificent animals,” Mr. Ben David says. “My Dad, Arthur Ben David, and those other old-timers did a lot of hunting and trapping and fishing.” They harvested otters.”

Today, the animals are protected.

Mr. Ben David said he learned a lot about otters raising Scuba Joe, and warns anyone who is contemplating installing an outdoor, freshwater fish pond, if you put a koi pond in your backyard, “Sooner or later an otter will pay you a visit.”