Development and application of microsatellite markers to address the population structure of the horse mackerel Trachurus trachurus

The genetic structure of the horse mackerel Trachurus trachurus was studied over almost its entire distribution range by genotyping 16 samples for 4 microsatellite loci. No temporal or spatial genetic differentiation was detected. A few statistically significant pairwise differences were most probably of stochastic nature, since they do not reveal any specific pattern. The lack of genetic differentiation in horse mackerel probably reflects the large population size and lack of barriers to the gene flow. However, this result should be viewed with caution, given the relatively low number of loci used in this study.