This invention relates to a method and a system for processing fish fillets conveyed by a conveyor means where the fish fillets are in an undercooled state, the method including: obtaining X-ray data of the fish fillets, processing the obtained X-ray data where the processing includes determining pin bones areas in the fish fillets and/or locations of undesired tissues, wherein the determined pin bones areas in the fish fillets and/or locations of undesired tissues is used as an operation parameter in automatically cutting around the pin bones areas and/or around the locations of the undesired tissues using at least one high pressure water jet for the individual fish fillets.
