Diet composition of wild Loligo vulgaris paralarvae along the West Iberian Peninsula coast

Prey identification in wild cephalopod paralarvae may be difficult by visual methods due to the ingestion of liquidised contents, while next-generation sequencing (NGS) can provide a better resolution. Molecular techniques such as NGS could be a good complementary approach to identify prey from family to species from the stomach content. This study shows for the first time the trophic interactions of Loligo vulgaris paralarvae in the western Iberian Peninsula. DNA from the dissected digestive system of 31 paralarvae was amplified with universal primers for mitochondrial cytochrome c oxidase subunit I gene (COI) and sequenced with the MiSeq platform. Overall, 130 Amplicon Sequencing Variants (ASV) were identified as prey (158,457 reads), being crustaceans the main prey accounting for 88.09% of the total reads, mainly represented by calanoids 73.22%, euphausiids 5.73%, and decapods 2.75%. Distance based linear model (DistLM) showed that the variables that most influenced the diet patterns were the spatial variables accounting for 46.92% of the total variation. In the southwest Galicia, the dominant prey were calanoids and euphausiids, while in the northern Galician coast the most important prey were siphonophores and myopsids. The prey of Portuguese paralarva could only be classified at phylum and class category identifying DNA of arthropods and hydrozoans. The results obtained in this study suggested that L. vulgaris paralarvae are generalist predators during their paralarval stage