Machine and a method for removing a dorsal fin from a fish

A machine for removing a dorsal fin from a fish, the machine comprising:

• a conveying system configured to convey a sequence of fish in a downstream direction while each fish of the sequence of fish is oriented with right and left sides of the fish on opposite sides of a vertical centre plane,
• a cutter tool, and
• at least one mechanical height control for controlling a height of the cutting tool relative to the conveying system, the mechanical height control comprising a frame carrying the cutting tool and a ski,
• wherein the ski is arranged to ride on the dorsal part of the fish while the frame is moving in a height adjustment plane based on the riding of the ski on the dorsal part of the fish, and wherein the frame is movable by a motion control between an upper and a lower position relative to the ski based on a position signal representing a position of a fish in the sequence of fish relative to the cutting tool.