One wants to grow his propane delivery business across the Casco Bay islands. Another wants to grow oysters on Islesboro. Still another aims to expand her social media marketing consulting, while yet another hopes her painting will bring in more income to the family.

What these four have in common — and what another 11 share — is that their businesses are based on Maine islands. And they graduated March 24 from ISLE (Island Sustainability through Leadership and Entrepreneurship Initiative), an intensive training program offered by the Island Institute in partnership with Leadership for Local Change

Peter Pellerin’s propane business on Chebeague Island is very much defined by island needs, and Andrew Kahrl’s dream of growing oysters depends on Islesboro’s shores. But Heather Wasklewicz of Peaks Island and Laurie Webber, a part-time resident of Matinicus Island, could run their businesses anywhere.

With energy costs worrying most home and business owners, and with prices even steeper on islands, Pellerin is proud of having been able to reduce the price of propane on Chebeague. Before starting the business, propane was about $3.80 per gallon.

“Now, the last delivery I did was $3.35 per gallon,” he said.

He’s no expert in the fuel, he admits, but Pellerin does know something about delivery, having worked on logistics for UPS for ten years.

“I educated myself on propane,” he said, and learned “There’s a surplus of it now because of ‘fracking,’ ” the controversial practice of fracturing ledge rock in pursuit of natural gas. Propane is a byproduct of that process; historically, propane came through oil exploration.

Propane poses no environmental hazard, Pellerin said. “It’s legal to disperse into the air,” he said.

Rather than deliver the 100-pound “bottles,” as propane companies call them, Pellerin decided to negotiate with a fuel company to buy the contents of a truck. He works with the driver of the truck, who comes onto the island, to make the rounds of houses and a couple of businesses that Pellerin has lined up, filling their tanks of all sizes.

“It took less than two-and-a-half hours to empty the truck,” he said, which pleased the driver.

Pellerin also is starting to install propane furnaces, water heaters, wall heating units and clothes dryers, work for which he is licensed by the state. Propane, at the price he is able to sell it, is more economical than oil, he said.

At his presentation at the ISLE graduation, Pellerin said he hopes to secure a delivery truck of his own, a barge, a pumping station and tank farm area and a service truck for appliance work.

“I know I can do this on other islands,” he said, bringing what he believes is cost-effective, clean energy to homes and businesses.

Kahrl of Islesboro also pitched his business plan for Dark Harbor Oysters in environmentally responsible terms. The oysters he hopes to raise would grow in bags that would sit in various inshore locations. One oyster can filter 50 gallons of water a day, he said.

“Social justice and environmental protection will be built into the company’s DNA,” he said. “We can use capitalist enterprise in a way that improves the world we live in.”

But Kahrl knows there are many bridges to cross before the shellfish become a cash crop.

He needs leases from the Department of Marine Resources to test some island sites, then leases for the actual growing operations, should the tests prove favorable. Matters of boat traffic, fishing, access, proximity to houses and security all are factors in choosing the sites, he said.

“We really need support for our public hearings,” he said at the graduation.

Kahrl is deliberative and cautious in his planning. If the testing, leases and finances come together, he anticipates putting oysters into the water four years from now and harvesting them three or four years after that.

His goal is to produce 1 million oysters a year.

“It’s the kind of business that has the potential to increase our community’s sense of identity and pride,” Kahrl said at the graduation.

Webber, who spends some weekends and the summer on Matinicus, hopes to grow her Sea Glass Graphics business to the point that she can move back to the island full time. For now, she lives on the mainland and works as an educational technician at St. George Elementary School.

“I’d like to do some graphic art,” she said, creating business cards, T-shirts, posters and brochures. She’s designed some websites, including one for Rockland’s Lobster Shack (lobstershackrockland.com) and for Matinicus Plantation’s municipal  government (matinicusplantation.org). And Webber also turns her Maine-based scenic paintings — watercolors, acrylics and pastels — into prints and notecards.

But her passion lies with a children’s book she wrote and is in the process of illustrating. Finding a publisher would complete the dream, she said.

Wasklewicz of Peaks Island has launched Sikiss Social Media that helps businesses navigate emerging social media trends, showing them how to get their services and products chatted up on sites like Facebook and Twitter.

“I’m sort of catering to the smaller businesses,” she explained, acting as a consultant who will teach those businesses how to do their own marketing.

“My niche is sort of personal collaborative work,” she said.

It’s a part-time endeavor, for now.

The ISLE program helped Wasklewicz learn about the importance of slowing down to communicate effectively, something businesses struggle with in the digital age.

“I really learned so much more about communication,” she said, “just general human interactions.”

Wasklewicz also is fired up about building connections between islands. The networks the ISLE program formed “can cross geographical barriers.”

ISLE brings entrepreneurs or would-be entrepreneurs to intensive weekend-long gatherings in late November/early December, January and March. Participants are linked with mentors, and are expected to then mentor other islanders.

Webber called the ISLE program a “life-changing experience.”

Kahrl also gave it high marks.

“This was a way of making a commitment to bring the idea into some form of completion,” he said, describing the program as a mini-MBA education in which he learned “how to open up the hood on a business enterprise.”