Spatial distribution and genetic structure of loliginid paralarvae along the Galician coast (NW Spain)

Abstract

Squids belonging to the cephalopod family Loliginidae have an important economic value for the small-scale fisheries in Galicia and recreative fishing. Early life stages of loliginids are studied along the Iberian coast to forecast their population abundance based on correct species identification, but visual identification of the paralarvae is not possible for this family. Molecular analyses using cytochrome oxidase subunit I (COI) have shown that the three most common species of loliginids in the Galician coast are Alloteuthis media, Loligo vulgaris and Alloteuthis subulata. This study compared the abundance and spatial distribution of the three loliginid species between the northern and southern waters of Galicia. Results showed that A. media is the most abundant in the south and A. subulata in the north, while L. vulgaris maintains similar percentage of frequency. Genetically, L. vulgaris and A. media have complex haplotype networks and high diversity indices, while A. subulata has a reduced haplotype network and low diversity indices. The genetic variability observed in COI data showed a consistent genetic flow between north and south Galicia and no population structuring was observed along the Galician coast with this mitochondrial marker. Fine scale studies with nuclear and mitochondrial markers are needed to have a better understanding of the population structure of this important resource.