Sepiolid paralarval diversity in a regional upwelling area of the NE Atlantic

Abstract

Sepiolid paralarvae are poorly studied, at least in part, because of the difficulty of accurate identification using morphological analysis. To unravel the biodiversity of sepiolid paralarvae collected in the Ría de Vigo during the upwelling season (2012)(2013)(2014), and to overcome the difficulties of traditional identification, sepiolid paralarvae were identified by amplifying the barcoding gene cytochrome c oxidase subunit I (COI). In addition, morphometric analysis (Generalised Lineal Models, GLM and Discriminant Analysis, DA) was used to identify morphometric patterns useful for paralarval species identification. Genetic barcoding successfully identified 34 Sepiola pfefferi, 31 Rondeletiola minor, 30 Sepiola tridens, 4 Sepiola atlantica, 2 Sepietta neglecta and 1 Sepiola ligulata. COI analysis also allowed us to infer that the paralarvae of the three most abundant species belonged to the same populations independently of the year sampled. GLM suggested that total length (statistically different among the three species) and tentacle length (statistically larger in S. pfefferi from the other two species) were good variables to distinguish among species. DA succeeded in separating S. pfefferi from S. tridens, but R. minor overlapped along the first axes with both species, decreasing the accurate classification rate to 67%.

Loliginid paralarvae from the Southeastern Gulf of Mexico: Abundance, distribution, and genetic structure

“…In the present study, we observed that D. pleii had a high haplotype and nucleotide diversity, according to the values proposed by Goodall-Copestake et al (2012), with no population structuring. The haplotype network presented a star shape also found in this species (Sales et al, 2017) and other loliginid species (Olmos-Peŕez et al, 2018;Roura et al, 2019;Garcıá-Mayoral et al, 2020) where many unique haplotypes radiate from few common haplotypes. This pattern indicates high gene flow, which suggests that there are no barriers preventing the spread of this species along and across the YS.…”

“…This is also true for the southeastern Gulf of Mexico (SGoM), where the loliginid squid fishery is mostly obtained incidentally as a by-catch from the shrimp and sardine fisheries, while catches per unit of effort are not recorded most of the time (Solıś-Ramıŕez et al, 1998; Comisio ́n Nacional de Pesca (CONAPESCA), 2018). The lack of reliable information limits the evaluation of the stocks and impedes the establishment of local management and/or conservation strategies (Ward, 2000;Olmos-Peŕez et al, 2018).…”

Preface: Recent advances in knowledge of the life of cephalopods

“…To address such problems for sepiolid species off western Spain, Olmos-Pérez et al (2017) combined the sequencing of the mitochondrial cytochrome c oxidase subunit I (COI) barcoding gene with simple morphometric measurements and morphological observations. Using statistical correlations, they were able to identify distinguishing morphological features with reasonable accuracy among the three consistently dominant sepiolid species.…”