Method and apparatus for determining quality properties of fish

An apparatus for determining quality properties of fish on the basis of light reflection, comprising:

• A. a reflection measurement device (5) having a light emitter and a light receiver (6) and positioners constructed and arranged for placing the reflection measurement device and the fish in relation to each other, the light emitter and light receiver (6) being directed towards an inner abdominal wall having peritoneum of the fish, light emitter illuminating an area of the fish through the peritoneum and the light receiver capturing light reflected from the fish;
• B. a registration unit connected to the light receiver of the reflection measurement device (5), the registration unit registering the intensity of reflected light in three or more different wavelength bands in the visible and near-infrared range, providing measurement results;
• and
• C. a calculation unit having an algorithm expressing a quality property of the fish from the light reflection of the inner abdominal wall with peritoneum, the calculation unit receiving said registered intensities of reflected light for communication into the algorithm for processing to calculate the quality property of said fish.