Beaches in Encinitas have remained open despite increased reports of tar balls washing ashore on North County beaches, city officials said. On Thursday, Oct. 7, the county Health and Human Services Agency advised the public to be cautious at beaches and avoid contact with tar balls. In an update on its website Friday, Encinitas also informed residents that they might see members of shoreline assessment teams working along the Encinitas coast evaluating tar balls found on the beaches in North County to determine their source. It is unclear whether the increased numbers are directly related to the oil spill off the Orange County coast, a county official said. Natural geologic processes may cause tar balls to wash ashore and visible oil hasn’t been detected, the official said.