Passengers will pay 50 cents more per trip to take the King County Water Taxi from Vashon to downtown Seattle starting March 1. Passengers with reduced fare permits will pay an additional 25 cents per ride.

The fare increase — the first one since the county began operating the ferry district three years ago — is expected to generate more than $150,000 annually, according to a news release. The revenue is needed to contribute to the county water taxi’s overall financial stability, the release said.

Meanwhile, ridership on the Vashon water taxi continues to increase, with 9 percent growth between 2010 and 2011, the ferry district says. The boat also frequently sails “at capacity,” according to Scott Davis, director of the county’s marine division for the Department of Transportation, meaning that riders were likely left on the dock.

Last year, it sailed at capacity 130 times, compared to 78 times in 2010. As a result, the ferry district is working with the U.S. Coast Guard to increase the Melissa Ann’s capacity from 150 passengers to 172.

Efforts are also underway to replace the district’s aging fleet of leased vessels and improve passenger staging areas.