Two of the five Manteca City Council members by the time December rolls around will have two years or less experience serving for the fourth time in 36 years.Richard Silverman’s decision Thursday not to seek a second term in the Nov. 6 election assures that it will happen.There are two council seats as well as the mayor’s post up for grabs in 10 months. Mike Morowit, who was elected with Silverman in 2014, has formally announced that he is seeing re-election. The only other candidate to formally announce so far is Manteca Planning Commission member Jose Nuno.Steve DeBrum, who was first to the council in 2003 and was elected mayor in 2014, has announced he’s seeking re-election.