An optimal allocation of aquaculture sites is also important for the preservation of biological diversity and habitats in general, and of particular importance for Norway's wild Atlantic salmon. This is particularly true for traditional salmon farming, but also for new species, such as cod and mussels. This development has probably contributed to major fish health problems experienced by the industry in recent years, particularly concerning the impact of pancreas disease and sea lice in Western Norway, where the density of farming facilities is the highest.