Spatial and temporal stability in the genetic structure of a marine crab despite a biogeographic break

Abstract

Elucidating the processes responsible for maintaining the population connectivity of marine benthic species mediated by larval dispersal remains a fundamental question in marine ecology and fishery management. Understanding these processes becomes particularly important in areas with a biogeographic break and unidirectional water movement along the sides of the break. Based on variability at 4209 single-nucleotide polymorphisms in 234 individuals, we determine the genetic structure, temporal genetic stability, and gene flow among populations of the commercially important mola rock crab Metacarcinus edwardsii in a system in southern Chile with a biogeographic break at latitude 42°S. Specimens were collected at eight sites within its geographic distribution, with collection at four of these sites was performed twice. Using population genetic approaches, we found no evidence of geographic or temporal population differentiation. Similarly, we found no evidence of an effect on gene flow of the biogeographic break caused by the the West Wind Drift Current. Moreover, migration analyses supported gene flow among all sites but at different rates for different pairs of sites. Overall, our findings indicate that M. edwardsii comprises a single large population with high levels of gene flow among sites separated by over 1700 km and demonstrate temporal stability in its genetic structure.

Integrating genetic and biophysical approaches to estimate connectivity in an isolated, insular system: case of the culturally important marine gastropod Monetaria caputdraconis

“…Different approaches have been developed to quantify this process, including the use of genetic variability (Palumbi, 2003;Hellberg, 2009;Lowe and Allendorf, 2010;Gagnaire et al, 2015;Veliz et al, 2021Veliz et al, , 2022 and biophysical modelling (Lett et al, 2008). The use of genetic markers allows to describe the extent of the marine populations (Cowen and Sponaugle, 2009), the dispersal potential of the species (Kinlan and Gaines, 2003), and the asymmetry of the migrant interaction between pairs of groups (e.g., Meerhoff et al, 2018).…”