Crab prices are still giving Bay Area consumers shell shock. So why not net your own at the nearest Bay wharf? Rangers from Golden Gate National Parks will be holding free crab catching classes on Saturday mornings 10 a.m. to noon March through October. They will be scheduled at the pier next to Fort Point at the west end of Crissy Field. Due to the limited space reservations are required. Please call (415) 556-1693.