Fine‐scale seascape genomics of an exploited marine species, the common cockle Cerastoderma edule, using a multimodelling approach

Abstract

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 FST = 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.

Multi-model seascape genomics identifies distinct environmental drivers of selection among sympatric marine species

“…3). Previous seascape genomic studies in temperate regions have frequently identi ed some measure of SST as the best predictor of genomic variation of marine invertebrates [9,11,12,25,28,63], which is most likely due to SST affecting both cellular processes, and life-history events such as spawning and larval development [59]. However, for P. angulosus, Trange and SSTmean best explained genomic variation, whereas SSSmean best explained the structure of C. punctatus.…”

Genome-wide Assessment Elucidates Connectivity and the Evolutionary History of the Highly Dispersive Marine Invertebrate Littoraria Flava (Littorinidae:Gastropoda)

“…The fine-scale genetic structure, therefore, should reflect a complex set of features, such as life-history traits, larvae features, and local adaptation [11]. However, only a few marine studies have attempted to link seascape factors with genetic differentiation patterns at the fine spatial scale [e.g., [45][46][47].…”

Biotic and abiotic factors shaping the genome of cockle (Cerastoderma edule) in the Northeast Atlantic: a baseline for sustainable management of its wild resources

“…The copyright holder for this this version posted December 18, 2020. ; https://doi.org/10.1101/2020.12.17.423063 doi: bioRxiv preprint of fisheries (Nielsen et al, 2009;Bernatchez, 2016). Genetic markers showing a significant departure, above or below the neutral dataset are potential outliers under divergent or stabilizing selection, respectively, which can unravel a fine-scale structure related to environmental variables critical for resources management (Vera et al, 2019;Coscia et al, 2020). Temperature, salinity and other abiotic factors have been suggested as potential drivers for adaptive differentiation in C. edule (Coscia et al, 2020), as in other marine species in the region (Vera et al, 2016;do Prado et al, 2018).…”

“…Genetic markers showing a significant departure, above or below the neutral dataset are potential outliers under divergent or stabilizing selection, respectively, which can unravel a fine-scale structure related to environmental variables critical for resources management (Vera et al, 2019;Coscia et al, 2020). Temperature, salinity and other abiotic factors have been suggested as potential drivers for adaptive differentiation in C. edule (Coscia et al, 2020), as in other marine species in the region (Vera et al, 2016;do Prado et al, 2018). In our study, the RDA analyses confirmed the effect of temperature in a wider geographical range, the major genetic subdivision north-south in the Northeast Atlantic being associated with a latitudinal annual mean temperature gradient of ~5.5 ºC between the warmest (Ria Formosa) and the coldest station (Dundalk).…”

“…Recently, Coscia et al (2020) analysed the genetic structure and connectivity among cockle populations within the Celtic/Irish seas using data from Restriction-site Associated DNA sequencing (RADseq) and a population genomics approach in combination with information on ocean conditions and larval dispersal modelling. They identified a significant genetic differentiation in a small geographical area (three groups; F ST = 0.021) mainly driven by salinity, larval dispersal by oceanographic currents and geographical distance.…”