A Watsonville man was arrested yesterday for possession of a loaded firearm and ammunition as a convicted felon and for violating his probation. Officers were on patrol on the 300 block of Bree Lane around 6 p.m. when they spotted suspected gang member, 18-year-old Raul Castillo Arana near his residence. Arana was on probation, prompting a search of his bedroom. Officers recovered a loaded handgun. He was booked into Santa Cruz County Jail.