Method and device for detecting the prone/supine position of fish conveyed by means of a conveying device

An apparatus for detecting the prone/supine position of fish conveyed in a longitudinal direction of the fish, comprising:

• a conveying device configured to convey the fish in the longitudinal direction of the fish;
• an optical scanning device designed and configured for optically scanning a ventral side and a dorsal side of the fish as a pair, and configured for determining a first brightness value profile of a first side and a second brightness value profile of a second side of a respective fish;
• an evaluation device configured to:
• determine a first ordered data series and a second ordered data series by ordering brightness values of the first brightness value profile and the second brightness value profile according to a predefined ordering criterion;
• determine a first median from the first ordered data series and a second median from the second ordered data series;
• and
• determine at least one differential value from the first median and the second median,
• wherein the evaluation device is furthermore configured to determine the prone/supine position by comparing the at least one differential value with at least one predefined reference value.