Abstract
As part of a research project on fish refrigeration, the efficiency of different cooling methods at sea is examined and compared to traditional icing techniques, with the aim of developing a prototype cooling system that can be used onboard. An experimental rapid fish cooling system using either spraying or brine immersion is installed on a trawler. The cooling dynamics of Mediterranean sardines (*Sardina pilchardus*) are studied for both methods, followed by an analysis of the thermal behavior of the treated sardines during storage in crates after icing. Both techniques prove to be equally effective in terms of thermal efficiency. Cooling time simulations based on fish mass show that a 5-minute treatment with seawater at -2°C achieves the desired temperature level (a core temperature below +5°C), which is up to four times faster than conventional icing methods. Such short processing times allow for continuous cooling. However, immersion requires larger quantities of liquid and a less compact installation compared to spraying. For this reason, the spraying technique will be preferred for developing a prototype onboard cooling system for sardines and small pelagic fish on trawlers.