RedactedNarrative: Operator was operating a PWC, LA-7547-FX, in Lake Pontchartrain near the Tchefuncte River. Operator's juvenile grandson, 5 YOA, was also on board the PWC, seated in front of Operator. While cruising at approximately 10-15 mph, the PWC struck an elevated trotline. The trotline caused a small tear in the rubber hand grip of the starboard side steering bar. The trotline then contacted the juvenile on the left side of the face and lips causing rope burn type injuries. Operator was struck in the left upper arm and received bruising and rope burn type injuries. The juvenile was treated by a dermatologist. Operator received no medical treatment. All PFD requirements were met and alcohol nor drugs are suspected to be a factor in the incident.