DOI: 10.5061/dryad.vdncjsz4r
title: Data from: Fine-scale genetic structure of small fish populations in islands: The case of brook charr Salvelinus fontinalis (Mitchill, 1814) in Saint-Pierre and Miquelon (France)

description: Island ecosystems, particularly vulnerable to environmental challenges,
 host many endangered native species. Diadromous fish, in particular, are
 threatened throughout their marine and freshwater habitats. The
 conservation of these species requires an in-depth understanding of their
 genetic diversity and structure, to better understand their adaptive
 potential. We investigated fine-scale population diversity and structure
 in native brook charr (Salvelinus fontinalis) by genotyping ten
 microsatellite loci in 244 individuals at three spatial scales in
 Saint-Pierre and Miquelon, France. We found limited genetic variability
 across the archipelago, with particularly low genetic diversity in one
 island, Langlade. A significant difference in allelic richness was also
 detected among the three islands, indicating a difference in genetic
 composition across the archipelago, probably induced by historical
 stocking actions on both Saint-Pierre and Miquelon. Finally, a strong
 genetic structure was detected across the archipelago among hydrosystems
 (overall FST = 0.19) and even within several of them. The presence of
 predominant inter-island gene flow combined with complete genetic
 isolation from certain hydrosystems, suggests that this contemporary
 genetic structure is the result of both natural demographic processes
 during the species post-glacial colonization, and recent restocking
 actions. The complex genetic structure of such isolated brook charr
 subpopulations highlights the importance of considering fine-scale genetic
 structure in conservation management.
description: We aimed to capture a total of 30 individuals per hydrosystems
 selected (ten in the upstream part, ten in the median part, and ten in the
 estuarine part) by electrofishing or traditional angling techniques
 (<em>i.e.,</em> cork, spinner or whip fishing). Fish captures
 were performed in each targeted sampled areas so that we cover the entire
 area as much as possible. Captures were made according
 to CCAC (UQAR CPA-89-22-246) and to the prefectural permit (no. 349).
 Following the capture, fish were anesthetized with eugenol 100% (Lotus
 Aroma, Sainte-Julie, QC, Canada), and killed by sectioning the spinal cord
 for further molecular analyses. The adipose fin was cut and preserved in
 95% ethanol. Genomic DNA was extracted using the QIAGEN “DNeasy Blood and
 tissue” kit (Qiagen, Hilden, Germany). Evidence of null alleles or large
 allele dropouts was detected for two <em>loci</em>
 (<em>SfoC88</em> and <em>Sfo177Lav</em>) with
 MICRO-CHECKER analyses hence those <em>loci</em> were
 discarded for further analyses but they are presented here all the
 same..
description: # Fine-scale genetic structure of small fish populations in islands: the
 case of brook charr Salvelinus fontinalis (Mitchill, 1814) in Saint-Pierre
 and Miquelon (France)
 [https://doi.org/10.5061/dryad.vdncjsz4r](https://doi.org/10.5061/dryad.vdncjsz4r) ## Description of the data and file structure This dataset contains the genotypes of 244 brook trout obtained for 12 loci microsatellite. Individuals were sampled from 11 hydrosystems belonging to distinct watershed distributed across the three main islands of the Saint-Pierre and Miquelon archipelago to evaluated their genetic diversity and population genetic structure at three spatial scales: islands, rivers, and positions within these rivers. Thanks to the 10 microsatellite loci selected, we found limited genetic variability across the archipelago, with particularly low genetic diversity in one island, Langlade. A significant difference in allelic richness was also detected among the three islands, indicating a difference in genetic composition across the archipelago, probably induced by historical stocking actions on both Saint-Pierre and Miquelon. Finally, a strong genetic structure was detected across the archipelago among hydrosystems (overall *F*ST = 0.19) and even within several of them. The presence of predominant inter-island gene flow combined with complete genetic isolation from certain hydrosystems, suggests that this contemporary genetic structure is the result of both natural demographic processes during the species post-glacial colonization, and recent restocking actions. The complex genetic structure of such isolated brook charr subpopulations highlights the importance of considering fine-scale genetic structure in conservation management. ### Files and variables #### File: Viana\_al\_Dataset.csv **Description:**  ##### Variables * Name: ID for each individual sample * Island: Island where the samples were taken * Hydrosystem: Hydrosystem where the samples were taken * Site: Specific site in hydrosystem where the samples were taken * SfoC115_1: First allele for the SfoC115 locus * SfoC115_2: Second allele for the SfoC115 locus * Sfo308Lav_1: First allele for the Sfo308Lav locus * Sfo308Lav_2: Second allele for the Sfo308Lav locus * SfoD75_1: First allele for the SfoD75 locus * SfoD75_2: Second allele for the SfoD75 locus * SfoC38_1: First allele for the SfoC38 locus * SfoC38_2: Second allele for the SfoC38 locus * Sfo177Lav_1: First allele for the Sfo177Lav locus * Sfo177Lav_2: Second allele for the Sfo177Lav locus * SfoC86_1: First allele for the SfoC86 locus * SfoC86_2: Second allele for the SfoC86 locus * SfoB52_1: First allele for the SfoB52 locus  * SfoB52_2: Second allele for the SfoB52 locus  * SfoD100_1: First allele for the SfoD100 locus  * SfoD100_2: Second allele for the SfoD100 locus * SfoD91_1: First allele for the SfoD91 locus  * SfoD91_2: Second allele for the SfoD91 locus  * SfoC88_1: First allele for the SfoC88 locus  * SfoC88_2: Second allele for the SfoC88 locus  * SfoC129_1: First allele for the SfoC129 locus  * SfoC129_2: Second allele for the SfoC129 locus  * SfoC113_1: First allele for the foC113 locus  * SfoC113_2: Second allele for the foC113 locus  * Missing values are indicate by a zero ## Code/software The file is in .csv format and can be read with any software that supports this format.