How does ice slow spoilage in harvested fish?

Ice is essential for the immediate preservation of harvested fish because it creates a low-temperature environment that significantly slows the spoilage process. This cooling method functions through two primary mechanisms:1

• Microbial Inhibition: By lowering the temperature, ice slows the growth of microorganisms that naturally inhabit fish and are responsible for contamination and decay.1
• Enzymatic Suppression: Fish are highly susceptible to structural degradation caused by endogenous enzymes—proteins that act as biological catalysts. Chilling the fish inhibits the activity of these enzymes, which would otherwise break down tissues, cause off-flavours, and reduce the overall quality of the flesh.123

Because fish possess a softer texture and less connective tissue than land animals, they are particularly vulnerable to rapid degradation after harvest. Consequently, immediate chilling in ice or refrigerated seawater is a critical step in fish processing to maintain freshness and safety. If immediate cooling is not possible, the fish must typically be sold and consumed on the day of harvest to avoid spoilage.1