Volunteers trickled into Pinole’s Bayfront Park Saturday morning, signing in, receiving cleanup instructions, grabbing plastic bags and heading for the shoreline. The gathering was part of California Coastal Cleanup Day, a statewide effort organized by the California Coastal Commission that brings volunteers together to remove trash from waterways throughout the state. In Pinole, about 80 or so people joined in the cleanup, organized by the city and the Friends of Pinole Creek Watershed. That was fewer than last year, when…