** Shares of dry bulk shippers down between 3-6 percent ** The Baltic Exchange’s main sea freight index, which tracks rates for ships carrying dry bulk commodities, down about 3 percent ** Baltic’s capesize index falls about 13 percent ** Clarkson Capital Markets analysts say weak spot rates and softening time charter demand signal a difficult 2015 ** Knightsbridge Shipping Ltd falls 6 percent, Safe Bulkers Inc about 4 percent, Scorpio Bulkers Inc about 4 percent, DryShips Inc about 3 percent, Navios Maritime Holdings Inc about 3 percent ** Up to Thursday’s close, the Dow Jones Global Shipping Index had fallen about 19 percent this year