Today the fleet is required to report the amount of bait in catch on a subjective scale (1-4) which do not provide an accurate picture of the danger of belly bursting. Following the fishermen's desire to find an objective method for predicting belly bursting, SINTEF Fisheries and Aquaculture has been working in a number of years with bait-and-belly bursting issues in pelagic catches.
As a result of several projects and a doctoral thesis, we have identified the enzymatic activities that leak from the fish's digestive system, causing the bursting. Furthermore, we tested two promising types of analysis which would identify the presence of proteolytic activity:
- Petri Dishes with gelatine: The activities have been found in ventral muscle appears to break down the gelatin. If an extract of the abdomen visibly breaks down the gelatin, it means that one has strong proteases present, indicating leakage of digestive enzymes since the muscle itself does not contain such strong protein-degrading enzymes.
- ATP luminometer: Measure amount of ATP in a sample using luciferase, which produces a photon (a light unit) per ATP molecule. If proteases are present in the sample, these could break down and therefore inhibit luciferase lighting productions.