PORTLAND — Less than a week after nomination petitions became available, new and familiar candidates are lining up to represent the city in the Maine Senate.

On Monday, City Councilor Jill Duson said she is running in Senate District 28, which includes the western part of the city and a portion of Westbrook.

The seat is now held by Democratic Sen. Anne Haskell, who is completing her second term.

Haskell endorsed Duson on Tuesday. She is Duson’s campaign treasurer, according to paperwork filed with the Maine Commission on Governmental Ethics and Election Practices.

“I am not seeking re-election, I made it clear some time ago,” Haskell said. “I am such a fan of (Duson’s) deliberative process. She will meet with people without having made up her mind and listen to them and use the information she gets in her decision making.”

Also on Tuesday, House District 43 Rep. Mark Dion, a Democrat and former Cumberland County sheriff, said he will also seek Haskell’s seat. Dion has not yet taken out nomination papers, but said he plans to make a formal announcement early next week.

Also in the race is former Rep. Ann Peoples, a Democrat who served four terms in Westbrook and was unable to run again in 2014 because of state term limits.

The term limits law, which prohibits more than four consecutive terms, also affects Senate District 27, where Democratic Sen. Justin Alfond, the former Senate president, is unable to seek a new term.

Rep. Diane Russell, D-Portland, who is completing her fourth term in House District 39, which encompasses the city’s East End and Casco Bay islands, has filed to run for Alfond’s seat.

She is joined by Dr. Charles Radis, who said Monday he has already been collecting signatures. Radis, a Democrat, has been a primary care provider for patients living on the Casco Bay islands.

Portland has eight House seats and two in the Senate, all held by Democrats. The primary election will be held June 14; the general election is Nov. 8.

Along with Alfond and Russell, Rep. Peter Stuckey of House District 42 will not be able to seek re-election. Democrat Benjamin Collings has filed to run for the seat, which covers the area along and north of Back Cove to Canco Road, Allen Avenue and the Falmouth border.

No other incumbents or challengers had filed for the remainder of the city legislative seats as of Monday.

The House District 36 seat, covering a portion of North Deering and west to the Westbrook boundary, is held by Rep. Denise Harlow, now in her third term.

Rep. Richard Farnsworth is in his second consecutive term serving House District 37, which covers the southern and western portions of the city along outer Congress Street and Brighton Avenue.

House District 38, encompassing the West End of the peninsula, is represented by Rep. Matthew Moonen, now in his second term. House District 40 Rep. Ben Chipman, who ran and won as an independent in 2010, 2012 and 2014, has enrolled as a Democrat in the district that covers the Parkside and Bayside areas.

Serving Libbytown and the Deering area, Rep. Erik Jorgensen is in his second term in House District 41.

Party-affiliated Republican, Democratic or Green Independent candidates must submit completed petition forms to the office of the Secretary of State by March 15 in order to be placed on the June 14 primary election ballots.

Unaffiliated candidates in Portland must submit their completed petition forms to the city clerk’s office by May 25. Once certified, the petitions are then forwarded to the Secretary of State by June 1.

The petitions are for candidates seeking elected federal, state or county posts. The number of signatures needed varies by office, and specific requirements are detailed in a candidates’ guide made available by the secretary of state’s office.

For legislative offices, candidates must be at least 21 years old to run for the Maine House of Representatives and 25 to run for the Senate. House candidates must gather at least 25 and no more than 40 signatures. Candidates for Senate must gather at least 100 and no more than 150 signatures.

All signatures must be from registered voters living in the district and members of the party where the nomination is sought.

David Harry can be reached at 781-3661 ext. 110 or dharry@theforecaster.net. Follow him on Twitter: @DavidHarry8.

Portland City Councilor Jill Duson is one of three candidates seeking the Democratic Party nomination in state Senate District 28.

State Sens. Anne Haskell, left, and Justin Alfond, both Democrats, will not be seeking re-election in 2016. Three candidates are already seeking to replace Haskell, two would like to replace Alfond.