Abstract: A conveyor transports fish along a path past a fish sex detector. A rotating fish-engaging member is mounted downstream of the detector above the path. According to the sex of a fish as detected by the detector, the rotating fish-engaging member is either shifted downward to kick the fish off the conveyor or held away from the conveyor out of engagement with the fish so that it continues to be transported downstream by the conveyor.

Abstract: Fish are oriented by laying them in random arrangement in the central portion of a vibrating trough, the opposite ends of which form passages slightly wider than the widest fish being sorted. Fish move headfirst toward the trough ends, and the movement of fish discharged in single file from such trough ends is accelerated to propel fish past detector means. Such detector means include a radiant-energy source and fish-sorting means responsive to energy from such source operable to deflect fish leaving such source for channeling the fish corresponding to a characteristic detected by the detector. Such characteristic may be sex, length or sidewise orientation.