Fish are aquatic vertebrate animals that are typically ectothermic (cold­blooded), covered with scales, and equipped with fins for motion and steering. They are very important as food for people around the world and are harvested from the wild or, farmed in much the same way as cattle and chickens.

The BIA measurement (reactance) of a recently caught and filleted[1] Walleye fish from Lake Erie is an example of how cells maintain their life characteristics after the fish is killed. The blood supply to the cells has stopped, inhibiting metabolic activity. However, the cells continue to live for a few days as indicated by high reactance values. Eventually cellular degradation will take place and reactance will drop. Refrigeration slows this process and freezing will destroy the cells, reducing reactance to virtually zero once thawed.

Note: A fresh whole (not filleted) fish will have very different characteristics. Reactance will remain high for a much longer period of time.

View Experiment 3.0