There will be four candidates on the ballot for two seats on the Board of Selectmen at Swampscott’s April 30 annual town election: former selectman Matthew Strauss, John Callahan, Charles Patsios, and Patryk Januszewski. There are also three candidates running for two seats on the School Committee: incumbent Jaren Landen, Amy O’Connor, and Carin Marshall. Board of Selectman chairman Rich Malagrifa, Selectman David Van Dam, and School Committee chairman Larry Beaupre are not seeking reelection. The annual town election will coincide with the special state primary for the vacant US Senate seat formerly held by John Kerry. The last day to register to vote is April 10.