Demand relationships between salmon and a number of wild-caught whitefish and shellfish species using both single equation models and linearised AIDS system framework. The system is well represented although autocorrelation were found in both approaches but this is less of a problem in the systems approach. A cautious interpretation of the results indicated that salmon had a long-run market relationship with the whitefish species of cod, monkfish, saithe, whiting and plaice and with the shellfish species of mussels, nephrops, scallops and shrimp. These groups contain the main seafood species consumed within the United Kingdom, and therefore should include most potential substitutes for salmon.