In the
case of Baltic cod, due to statistically insignificant, near 0, values of FIS,
the hypothesis of high migration between eastern andwestern subpopulations
was rejected.
A second reason for low FST values could be the
large effective size of the population (Ward et al., 1994) observed in
Baltic subpopulations of cod.
Low FST values could also be an effect of recent
origin of the population after postglacial expansion, as suggested
by Pampoulie et al. (2008) for Atlantic cod.