Abstract: A method and apparatus for evaluating a live shellfish (S), especially a lobster or crab, to determine the MC, or meat ratio (meat divided by meat plus water). A pair of transducer devices (12, 14) are pressed against opposite sides of the shell of a live shellfish to determine the velocity of sound through it. The transducer devices are pressed without substantially deforming or cracking the shell, to avoid injury to the shellfish. Good acoustic coupling to the shell is achieved by applying a sound-transmitting gel (240, 242) to the face of each transducer device. If the velocity 1560 m/sec, this indicates an MC of 7%, indicating that the shellfish is unsuitable for harvest. If the velocity 1660 m/sec. then this indicates an MC of 19%, which indicates that the shellfish is ready for harvesting, that is, for shipping to restaurants or markets for human consumption. A velocity of 1600 m/sec. indicates an MC of 12% which is about a borderline between acceptance and rejection.