3.1.4. Removal of tails earlier in the production
As mentioned earlier, the mackerel are de-headed and gutted before the freezing process. Before the tails were left on the fish during the freezing process. The result was that many tails broke off in the freezing house while others fell off during the processing and ended up in the wastewater stream. A valuable by-product was lost and the tails contributed to higher COD levels. Hence, around 1995, the company decided to cut off the head and tail simultaneously before freezing the fish. The result was reduced COD levels, more waste which could be sold as a valuable by-product, and increased cold storage capacity [23].