AUGUSTA — Lt. Jay Carroll of Southwest Harbor, a 23-year veteran of the Maine Marine Patrol, has been promoted to colonel and will take over as chief of the state’s marine law enforcement branch.

He will begin work in his new role Monday, replacing Jon Cornish, who officially retires April 5 after 34 years of service.

“I am honored to take this next step in my career and look forward to working with the talented, hardworking marine patrol professionals whose efforts are critical in sustaining our state’s valuable marine resources,” Carroll said in a statement.

“I have great confidence in Lt. Carroll’s ability to excel in this leadership role,” said Patrick Keliher, commissioner of the Maine Department of Marine Resources. “His depth of professional experience and accomplishments as an officer, a specialist, a sergeant and a lieutenant on Maine’s increasingly busy Downeast coast position him well to guide the marine patrol into the future.

“Lt. Carroll has done an outstanding job throughout his career. He has led the officers, sergeants and boat specialists in Division II through a period of significant change in our state’s commercial fishing industries, including historic growth in value and abundance of lobster, and challenges associated with Maine’s lucrative elver fishery.

“He has maintained excellent working relationships with the commercial fishing industry and has set a standard of exceptional problem solving and communications for the officers in Division II.”

Carroll  grew up in Hancock County and has a lifelong connection to the marine patrol.

“My father, Jim, was the very first lieutenant to occupy the Division II headquarters here in Lamoine,” Carroll said in 2014. “My uncle John Carroll and my cousin Richard LaHaye Jr. both served as marine patrol lieutenants, and my cousin Tim Carroll also served in the marine patrol.

“Marine patrol for the Carroll family is much like the commercial fishing industry. It is a family business,” he said.

Carroll began his law enforcement career in 1994 as a reserve officer in the Bar Harbor Police Department. He then served as a deputy with the Knox County Sheriff’s Office before joining the marine patrol in 1996. Since 2014, he has served as lieutenant of Division II, which stretches from Searsport to the Canadian border.