"Pathogens are a major challenge to fish farming, particularly under the dense stocking conditions that are typical of aquaculture, and vaccination is a major approach to protect from diseases," said Prof Christopher Secombe, head of the Scottish Fish Immunology Research Centre. The new research will help them to target vaccine research more effectively. Cod is one of the five fish species most commonly eaten in the UK. British consumers spent more than £313.3m on cod last year.