Oceanographic processes shape genetic signatures of planktonic cephalopod paralarvae in two upwelling regions

• Published in: Progress in oceanography 2019-01, Vol.170, p.11-27
• Main Authors: Roura, Álvaro, Amor, Michael, González, Ángel F., Guerra, Ángel, Barton, Eric D., Strugnell, Jan M.
• Format: Article
• Language: English
• Subjects: Cephalopod paralarvae; Eastern boundary upwelling system; Northeastern Atlantic; Octopus vulgaris; Planktonic dispersal patterns; Seascape genetics; Upwelling filaments
• ISSN: 0079-6611; 1873-4472
• DOI: 10.1016/j.pocean.2018.10.005

[Display omitted] •Cephalopod paralarval richness was 2× higher in Moroccan than Iberian waters.•Three planktonic dispersal patterns were identified in the Iberian–Canary current upwelling system.•The interaction between vertical behaviour and oceanography led to these 3 dispersal patterns.•Each planktonic pattern had different haplotype and nucleotide genetic signatures.•Octopus vulgaris paralarvae shift within upwelling filaments from coast to ocean. The planktonic paralarval stage of cephalopods (octopus, squids and cuttlefishes) is an important dispersal phase, particularly of benthic species, that lasts from days to months. Cephalopod paralarvae modify their vertical position in the water in upwelling ecosystems and such behaviour influences their spatial distribution and genetic structure, but to what extent? In this work specific water masses were sampled with Lagrangian buoys in two contrasting upwelling systems (Iberian Peninsula and Morocco) of the Iberian–Canary current eastern boundary upwelling (ICC) in order to: (i) identify the cephalopod assemblage in the different upwelling systems (ii) define their planktonic dispersal patterns and (iii) analyse the effect of different dispersal patterns on genetic structure and connectivity. Cephalopod paralarvae were identified using the cytochrome c oxidase subunit I gene (COI), revealing 21 different species and Fst values showed no population structure between both upwelling systems. Cephalopod species richness was two times higher in the Moroccan upwelling than in the Iberian Peninsula, with an undescribed Ancistrocheiridae species identified in Moroccan waters. Three common planktonic dispersal patterns were identified in the ICC: coastal, coastal-oceanic and oceanic. Coastal and oceanic dispersal patterns favoured spatio-temporal paralarval retention or “schooling” of different cohorts over the continental shelf and continental slope in 9 and 11 species, respectively. Such spatio-temporal retention was reflected in the complex haplotype networks and high nucleotide/haplotype diversity recorded for these two groups. The only cephalopod species displaying a coastal-oceanic dispersal pattern was Octopus vulgaris, where low nucleotide and haplotype diversity was observed. The observed decline in genetic structure resulted from the dispersal of similar cohorts within upwelling currents and upwelling filaments to the oceanic realm. Seascape analysis revealed that cephalopod paralarvae from two coastal u