RedactedNarrative: V1 was operating on plane southbound inside a marked swim zone off St. Pete Beach. Swimmer 2 was swimming inside the swim zone. v1 struck S2 in the left shoulder and back of head.  after the impact operator of v1 fell overboard.  Operator re-boarded v1 and fled the area.  Swimmer was transported to hospital.  another deputy located a subject matching the description of the operator/suspect.  a witness also had photos of the operator/suspect at the time of accident.  The operator fled on foot and was apprehended.   Approximately one hour later I received a phone call from Florida Fish & Wildlife Commission Officer who advised he located the PWC at Egan Park Boat ramp. The subject claiming ownership of the vessel was an acquaintance and advised Operator had been riding the PWC. The vessel was impounded for the purpose of an inspection. During the inspection it was found the vessel's registration had expired on 07/26/2007. During the time the vessel was impounded it was re-registered. The transaction date was 05/14/2015, five days after the crash. Operator was issued three citations, two of which were criminal.  Subject suffered IMPACT IN AREA OF LEFT SHOULDER BLADE THEN BACK OF HEAD. CONTUSIONS AND BRUISING IN AREA OF IMPACT.