Monitoring Climate Change Impact on the Genetic Population Structure: The Case of the Fivebeard Rockling (Ciliata Mustela, Linnaeus, 1758) In Its Southern Limit of Distribution

Abstract

Ciliata mustela is a marine inshore fish which occurs from central Portugal to northeastern Norway. We studied the population structure of this species using cytochrome b gene and the first intron of the nuclear S7 ribosomal protein gene and samples ranging from central Portugal to Gullmars Fjord, Sweden. We tested the following alternative hypotheses: 1) is the Portuguese population of the fivebeard rockling self-sustainable? or 2) is this population dependent on migrants from the north? We found no detectable subdivision among locations. Genetic diversity indices did not change along the study area. The data support persistence during one or several glacial cycles and a rapid expansion about 10 thousand years ago. In Portugal the populations of this species are strongly affected by climatic oscillations with severe reductions in warm years (bellow detection) and recoveries in cold years. We found that the percentage of private haplotypes is consistently lower in Portugal than in other locations. Our results support the hypothesis that the Portuguese population is mainly dependent on migrants from northern locations. We discuss the possibility of using species as C. mustella to monitor short term effects on the genetic structure of populations and their relation with climate change.

Genetic hypervariability of a Northeastern Atlantic venomous rockfish

“…Another caveat is using only one mitochondrial and one nuclear marker in a day and age where next-generation sequencing producing thousands of markers are being increasingly used. This study is in line with previous research in the pursuit for patterns and processes involved in the phylogeography of the species from the North-East Atlantic (e.g., Bargelloni et al, 2005;Debes, Zachos & Hanel, 2008;Francisco et al, 2011;Robalo et al, 2013a). These previous studies used the same set of markers, allowing across species comparisons and multi-species approaches (e.g., Robalo et al, 2012;Robalo et al, 2013b;Francisco et al, 2014;Almada et al, 2017;Castilho et al, 2017) while revealing very distinct patterns.…”

Time matters: genetic composition and evaluation of effective population size in temperate coastal fish species

“…While the present study used only one geographical location and two genetic markers, these apparent limitations allowed a rigorous comparison with data from several species collected in the same area over the past fifteen years and using the same two markers (mitochondrial control region and nuclear S7) (e.g., Domingues et al, 2006;Almada et al, 2012;Robalo et al, 2013;Francisco et al, 2014;Stefanni et al, 2015;Almada et al, 2017;Pappalardo et al, 2017), which facilitated comparison and calibration of genetic diversity results. Thus, it was possible to observe the high genetic diversity pattern found in several coastal fish populations in western Portugal (e.g., D. vulgaris (Stefanni et al, 2015) and Labrus bergylta (Almada et al, 2017)).…”

“…Over the last four decades, we have assembled extensive knowledge on the genetic characterization of marine organisms, mainly concerning the spatial distribution and structuring of populations (e.g., Knutsen et al, 2007;Plank et al, 2010;Robalo et al, 2013;Riginos et al, 2019;Verry et al, 2020). With this information, it is now possible and relevant to understand how these patterns behave through time.…”