Genetic structure in the blue and red shrimp Aristeus antennatus and the role played by hydrographical and oceanographical barriers

The blue and red shrimp Aristeus antenantus supports an important commercial fishery in the Western Mediterranean, adjacent Atlantic waters and Mozambique Channel (western Indian Ocean). This study investigates its genetic structure by examining a total of 506 individuals from Mediterranean, Atlantic and Indian Ocean locations. In order to identify putative genetic stocks, sequences from 16S rDNA (546 bp) and COI (514 bp) genes were used. Genetic diversity, estimated by haplotypic and nucleotidic diversity, was lower in the Western Mediterranean than in samples from other locations. The high haplotypic diversity of the Eastern Mediterranean, Atlantic and Indian Ocean samples reflects the occurrence of a number of private haplotypes, which are also responsible for significant genetic divergence between these samples and the Western Mediterranean ones. The analysis of mismatch distributions, neutrality tests, and star-like patterns present in the network of haplotypes provided consistent inference of past population expansion in the Western Mediterranean, Atlantic and Mozambique Channel regions. Our study provides the first evidence of genetic structuring in A. antennatus across its distributional range.