Calculating Quantities of Ice for Cooling and Maintenance of Freshly Harvested Fish at Sea

A new generalized model for predicting quantities of ice to cool and maintain freshly harvested fish at sea in insulated boxes is presented. The model addresses the universal need for fisherman to know in advance of going to sea just how much ice will be needed to cool down the expected day's catch to a desired temperature, maintain the catch, and to allow for losses. Illustrative predictions are presented for southern bluefin tuna (SBT) (Thunnus maccoyii) for a range of day's catch from 2000 to 8000 kg in ambient temperature ranging from 15 to 35 degrees C. The amount of ice needed to cool down SBT from an initial uniform harvest temperature of 28 degrees C to a maintenance temperature of 5 degrees C is shown to be the controlling contribution to total ice needed. Predictions highlight that a useful, safe rule-of-thumb is 1 kg of ice will be needed for each 3.5 kg of SBT. Importantly, the model is based on fundamental principles and predictive accuracy is demonstrated to be largely insensitive to a range of assumptions including volume of the void in the insulated boxes and overall coefficient of heat influx from ambient. The model can be used to predict the number of insulated boxes of defined dimension that will be needed to cool and hold the fish, ice and water for a wide range of fish species. It will be of interest to fisherman and boat owners and agents who invest in ice to preserve fish at sea.