The campaign to bring high-speed internet to Chappaquiddick is short the required number of subscribers, with a little more than two months to go before the mid-December deadline.

Residents who have advocated for Comcast service said their current estimates predict that 200 homeowners will have signed on as subscribers and committed the required $2,139 in up-front costs by December.

An additional 70 homeowners are needed before Dec. 19, however, according to a long-negotiated agreement between the town of Edgartown and Comcast.

There is still time to meet that goal, but if it isn’t met, an aggressive fundraising effort aims to make up the difference, Chappaquiddick resident Dr. Dennis Goldin told selectmen at their regular meeting Monday.

Residents of the small island have pledged another $150,000 to cover the shortfall in subscribers, and have raised an additional $40,000 to cover the contribution of another 20 residents who are in need of support.

The state has also appropriated an additional $50,000 for broadband service from Edgartown to Chappaquiddick, as part of a bill promoting economic growth.

In addition, Mr. Goldin said the subscriber minimum was originally determined based on a misconception that there were 540 homes on Chappaquiddick. Comcast agreed to the deal if a half the homes signed up for service, but in fact, there are just over 400 homes.

He told selectmen that the demographics of Chappaquiddick have changed, and needs for internet service have intensified.

Chappaquiddick resident Dr. Paul O’Donnell also made a plea for the selectmen’s support.

He said as the Island’s only resident oncologist, he needs consistent access to Massachusetts General Hospital’s electronic medical records.

“I have to confess that right now with the provider that I do, the service is so unreliable that half the time I cannot connect to the medical records for the patients that we serve on Martha’s Vineyard,” he said.

Mr. Goldin said he thought the contract had already been amended, and could be modified again.

“It is going to require you guys to go to bat for us to amend the contract,” he told the board.

Selectmen said they would continue to support the project.

“We are not going to rest until we close the gap,” said board chairman Arthur Smadbeck. “It’s good to have the information and some of the points you make we will be able to use so thank you for coming in and giving us the update.”

In other business, animal control officer Barbara Prada presented her quarterly report to the selectmen.

By far, the most calls she fielded since the beginning of April concerned dogs. Ms. Prada counted a total of 415 calls throughout the spring and summer. A fourth as many concerned cats. Ms. Prada also received 88 calls about other animals, including four snake calls, two about seals and four concerning a macaw.

“The snake calls were pretty abundant; garter snakes and black racers,” she said. “There are a lot of animals out there that people don’t realize are out there.”