Distinction between highly migratory Northeast Arctic cod and stationary Norwegian Coastal cod represents an important management issue. They overlap on the same spawning grounds where they are harvested, but display highly different abundences. This necessitates alternative management strategies. The bi-allelic genetic marker, pantophysin (Pan I), has been widely used as a diagnostic marker to discriminate between these two stocks. However, it has been proposed that this locus, or another gene(s) on chromosome 1 where it is located, may be under strong divergent selection between these two stocks. In order to address this, we compared relative survival rates between different Pan I genotypes in common garden pedigree-controlled experiments conducted in a temperature-controlled laboratory facility, and mesocosms. We found no evidence of departure from the expected 1:2:1 mendelian ratio for any of the three genotypes during the egg stage, while both the 6 and 12 °C temperature regimes in the laboratory experiment weakly favoured the Pan IAA genotype thereafter. No difference was observed between genotype survival in the mesocosm experiments. These results demonstrate that there are no clear advantages of certain Pan I genotypes under the experimental conditions observed.
Data from biological experiment with fish from larval to juvenile stage. Data contains grouping code, genotype for Pantophysin, length and weight.