It happened Halloween morning. Thirty youngsters picked up cans of blue spray paint and went downtown in broad daylight into Oak Bluffs to use them.

But the messages they painted on the streets weren’t graffiti. Plus, they had the full support of grownups.

The youngsters painted stenciled words next to storm drains under the supervision of Oak Bluffs shellfish constable David Grunden, as part of his broadening effort to raise public awareness about protecting coastal ponds.

“Don’t pollute, fish are cute” read one message.

“Little drains can cause big problems,” read another.

The slogans were created in class by fifth and sixth grade science students at the Martha’s Vineyard Public Charter School to make a statement about protecting the environment.

Ten-year-old Oren Osnoss of Chilmark, wearing a pumpkin orange safety vest, got several chances to paint. The idea of the message was important to him, he said. He described himself as an avid fisherman and said protecting Island waters from pollutants is important to the fish and to him.

— Mark Alan Lovewell

Storm drains regularly carry rainwater and empty out into the harbor but what Mr. Osnoss and his classmates were trying to do is make a statement to anyone thinking of dumping something unpleasant and harmful in them.

Anna Cotton, a math and science teacher, said her students were looking at the Island environment with specific interest in the watershed. The watershed is that area of land where anything like rainwater and pollutants entering the ground contribute to the quality of the water in a coastal pond. The Island landscape is a watershed to a lot of Island ponds and harbors. Even drainage in West Tisbury can have an impact on Sengekontacket Pond in Edgartown and Oak Bluffs.

A week ago Wednesday, Suzan Bellincampi, the director of Felix Neck Wildlife Sanctuary, came before Ms. Cotton’s students to talk about the importance of protecting the groundwater as a way to protect shellfish and fish in coastal ponds. They talked about the storm drain painting project and how it might help.

The initial idea of slogans came to Mr. Grunden after visiting other coastal communities on the West Coast. He said he’d seen similar programs in Seattle and at Monterey. He said he was further inspired by an exhibit at the Monterey Bay Aquarium.

The exhibit brought home the idea of doing something in Oak Bluffs. He coordinated the effort with Ms. Cotton and Miss Bellincampi at Felix Neck. He made the stencils and borrowed the safety vests, necessary to make the project safe on the edge of especially well-traveled roads.

Justen Walker, education coordinator for Felix Neck Wildlife Sanctuary, was on hand to help. She said she recalls seeing the effort in other coastal communities and it could be taken up by other Island towns.

Getting out of the classroom and out in the field is a perfect idea for her students, Ms. Cotton said.

“This is great science,” she said. “It raises their awareness about the issues. And these kids are at the age where they want to be a part of the world. They want to have an impact. We are always look for opportunities where our students can make a difference.”

Ten-year-old Tully McDonough was a bit apprehensive when he first heard of the project.

“Graffiti? I thought that we were going to paint the words on the street,” he said, waving his hand to suggest that the writing would be freestyle. “That is not good.”

“But when they said stencils, that made sense. We got permission and we are not in trouble,” he said, smiling.

At the western end of the Oak Bluffs harbor, Mr. Grunden showed the students where a storm drain pipe carries all the runoff from New York avenue into the harbor. He said the first half inch of rainfall brings 90 per cent of the pollutants from the street into the harbor. That first half inch of rainfall usually translates to about 35 pounds of sediment and debris.

After the students painted signs on storm drains near Our Market, they headed back to the center of town. Gavin Fynbo of Chappaquiddick noted that he was surprised at how many cigarette butts covered the lush grass at the edge of the road.

Ms. Cotton said the charter school administration and teachers have decided this year to be more environmentally friendly. They are exploring ways to cut down on the costs of fuel and paying more attention towards recycling.

She said the next phase of study will shift from coastal waters to the ocean and then on to weather.

Afterward, Mr. Grunden said, “This was a great success. They’ll remember this for the rest of their lives. It helps instill the message.”