ROCKLAND — A shortage of mariners is the main cause of the cancellations of ferry runs to serve the islands of Penobscot Bay.

The Maine State Ferry Service has cancelled 20 Islesboro runs this week. Between May 9 and July 4, a total of 29 Maine State Ferry Service runs involving all islands had to be cancelled, said Maine Department of Transportation Director of Communications Paul Merrill.

“Most of these impacts are due to ongoing staffing challenges,” Merrill said. “In May, the commissioner notified Maine State Ferry Service Advisory Board members and local officials of possible upcoming service disruptions. Many ferry service employees have offered to work overtime or stepped outside of their normal roles to fill in on vessels to help keep things running.

“We understand how vital the Maine State Ferry Service is to the coastal and island communities, and we don’t like having to cancel ferry runs — especially on short notice. In order to run a ferry, we must maintain minimum staffing levels, and it has become increasingly challenging to maintain those levels,” the transportation spokesman said. “There is very little redundancy in our staffing schedules right now.

“Our crews have been working extra shifts and making other sacrifices in order to keep the ferries running as much as possible. We have been trying to recruit and retain more crew members by offering pay stipends and bonuses, but the challenges still remain. We are still working to find ways to remedy the staffing situation and find the best way to communicate service impacts to the communities that rely on the ferries.”

Merrill said there can be different reasons for specific service disruptions, but most are compounded by the inability to recruit or retain crew members due to a widespread mariner shortage. Other ferry services are experiencing similar problems, he said.

“With a workforce shortage like this, the opportunities grow for credentialed workers to take higher-paying jobs elsewhere. With crew numbers as low as ours, one person unexpectedly out for an illness or a COVID-19 positive test can create a significant service issue,” he said.

The Ferry Service has 29 total Able Bodied Seamen and Ordinary Seamen positions, including both full-time and part-time workers. Merrill said the Ferry Service is actively recruiting for seven more full-time ABs and two OSs.

The Ferry Service has 52 full-time employees who crew ferry vessels (able seamen, ordinary seamen, engineers and captains). Of those, 11 are currently unavailable to work, Merrill said.

Able Bodied Seamen are paid $22.78 per hour. Ordinary Seamen are paid $17.54 per hour. Engineers are paid $28.27 per hour. Captains’ pay ranges between $29.22 per hour and $39.75 per hour.

The Ferry Service serves Vinalhaven, North Haven, Islesboro, Swan’s Island and Frenchboro.