Joseph Payne, Maine’s first baykeeper, is calling it quits after spending more than two decades leading the fight to protect Casco Bay from pollution.

Payne, who was hired as the Casco Baykeeper in 1991, issued a statement on Thursday, announcing that he plans to retire next month. A national search for his replacement will begin next year.

The nonprofit organization that Payne works for — Friends of Casco Bay — is on the campus of Southern Maine Community College in South Portland.

In his announcement, the 67-year-old Payne said he is leaving the position to spend more time with “the Keeper of the Keeper,” his wife, Kim. The couple live in Westbrook.

“Protecting the bay has been about the work, but more than that it’s been about the people I have met along the way,” Payne said. “Twenty four years ago, I wasn’t exactly sure what I was getting into. What I found out was that there were plenty of us who care about this community and want to do our part to ensure that the Bay is passed on to the next generation better than we found it.”

When Payne was hired as the organization’s first paid staffer, he became the state’s first baykeeper and only the seventh baykeeper in the world. There are currently 240 baykeepers – also known as waterkeepers – worldwide.

Payne described Casco Bay as the coastline, islands and ocean between Cape Elizabeth and the mouth of the Kennebec River in Phippsburg.

Over the years, Payne has introduced legislation, overseen a water quality testing program, met with landowners, and spoken out against environmental threats to Casco Bay.

“A baykeeper stops pollution from going into the bay,” he said. “That can involve installing a pipe or it can involve legislation.”

Cathy Ramsdell has served as executive director of the Friends of Casco Bay for 12 years. She said the communities on Casco Bay should feel fortunate to have someone as devoted as Payne to making sure that their quality of life is being protected from environmental threats. “For us to have a public advocate as devoted as Joe has been, is wonderful,” Ramsdell said. “What a gift he has been. He has brought the Bay to the forefront of the public’s attention.”

Payne said his retirement will become effective Jan. 9.

Payne said he was once jokingly asked by a reporter where he kept the bay, a reference to his title. “I told him, in the public eye,” Payne said. “We’ve raised public awareness. People can’t love the bay until they know all about it.”