Optimizing design and operation of chilling tank for Atlantic salmon

Abstract

Farmed salmon is a large export product from Norway. After the salmon is stunned and killed, it is often transported to large tanks for bleeding, chilling and buffering before gutting and further processing. The temperature of the fish into the processing plant is varying, but it is necessary to cool down the fish fast, both to reduce bacterial growth and to maximize yield. In this paper, a demonstration tank was set up and different operational regimes were tested. Refrigerated sea water (RSW) was used for chilling of the fish. Killed and bled salmon was used to see how the fish was located inside the tank, something which can be very difficult in a production tank where the chilling water is unclear because of blood. The flow pattern through the tank was registered. Operation which resulted in lowest contact between the fish gave best heat transfer and therefore best chilling.