BAY SHORE - State Sen. Owen Johnson (R-Bay Shore) today announced his retirement, closing the book on a 40-year career of serving the people of southwestern Suffolk County.Johnson has served in the state Senate since the early 1970s, a span that's seen eight different governors. At age 83, Johnson is the longest-serving member of the state Senate. Islip Assemblyman Phil Boyle hopes to succeed Johnson, arguing that it's important to keep the seat in Republican hands. Suffolk County Legislator Ric Mantano, the Democrat seeking the same office, argues that he's better suited to serve the district. Voters will pick their next senator in November.