Fine-scale seascape genomics of an exploited marine species, the common cockle Cerastoderma edule, using a multi-modelling approach

• Published in: Evolutionary Applications
• Main Authors: Coscia, Ilaria, Wilmes, Sophie-Berenice, Ironside, J.E., Goward Brown, Alice, O'Dea, Enda, Malham, Shelagh, McDevitt, AD, Robins, Peter
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Irish Sea; RADseq; larval dispersal; particle tracking; population connectivity; redundancy analysis; North West Atlantic
• Online Access: https://research.bangor.ac.uk/portal/en/researchoutputs/finescale-seascape-genomics-of-an-exploited-marine-species-the-common-cockle-cerastoderma-edule-using-a-multimodelling-approach(1f06a250-b389-4377-b703-9a92aa826e9c).html; https://doi.org/10.1111/eva.12932; https://research.bangor.ac.uk/ws/files/27892654/2020Fine_scale_seascape_genomics_of_an_exploited_marine_species.pdf

Population dynamics of marine species that are sessile as adults are driven by oceanographic dispersal of larvae from spawning to nursery grounds. This is mediated by life-history traits such as the timing and frequency of spawning, larval behaviour and duration, and settlement success. Here, we use 1725 single nucleotide polymorphisms (SNPs) to study the fine-scale spatial genetic structure in the commercially important cockle species Cerastoderma edule and compare it to environmental variables and current-mediated larval dispersal within a modelling framework. Hydrodynamic modelling employing the NEMO Atlantic Margin Model (AMM15) was used to simulate larval transport and estimate connectivity between populations during spawning months (April-September), factoring in larval duration and interannual variability of ocean currents. Results at neutral loci reveal the existence of three separate genetic clusters (mean F ST = 0.021) within a relatively fine spatial scale in the north-west Atlantic. Environmental association analysis indicates that oceanographic currents and geographic proximity explain over 20% of the variance observed at neutral loci, while genetic variance (71%) at outlier loci was explained by sea surface temperature extremes. These results fill an important knowledge gap in the management of a commercially important and overexploited species, bringing us closer to understanding the role of larval dispersal in connecting populations at a fine geographic scale.