Are vertical behaviour patterns related to the pantophysin locus in the Atlantic cod (Gadus morhua L.)?

Throughout their geographic distribution, marine fish species often form subpopulations with limited connectivity, among which individuals display a variety of migratory behaviours. Fish behaviour experiments using Data Storage Tags (DSTs) have been useful to define the natural movement of individuals. In Icelandic waters, such experiments have indicated the presence of two distinct behaviour types of the Atlantic cod Gadus morhua, related to vertical migrations and habitat choice in feeding migrations. Some individuals have been shown to stay most of the time in shallow waters characterised by the seasonal trend in temperature for the shelf waters, while other migrate to deeper and colder waters where most of them forage in temperature fronts characterized by highly variable temperatures. The analysis of the pantophysin locus (Pan I) of the same individuals revealed that individuals carrying the Pan I AA genotype are likely to display a shallow water feeding migrations while individuals carrying the Pan I BB genotype preferred deeper waters and forage near thermal fronts. The heterozygote exhibited both type of behaviours. This study therefore suggests that further research need to be done on the pantophysin locus and its potential effects on cod phenotypes to assess the potential relationship between this locus and the behavioural types described.