Phylogeography of isolated freshwater three‐spined sticklebackGasterosteus aculeatuspopulations in the Adriatic Sea basin

Abstract

Analyses of mitochondrial (mt) DNA and microsatellite variation were carried out to examine the relationships between 10 freshwater populations of three-spined sticklebacks Gasterosteus aculeatus along the eastern coast of the Adriatic Sea. Partial sequences of the mtDNA control region and cytochrome b gene, in addition to 15 microsatellite loci, were used to analyse populations from four isolated river catchments. Results uncovered an Adriatic lineage that was clearly divergent from the European lineage, and confirmed that the most divergent and ancient populations are located within the Adriatic lineage as compared with other European populations. Two northern Adriatic populations formed independent clades within the European mitochondrial lineage, suggesting different colonization histories of the different Adriatic populations. Nuclear marker analyses also indicated deep divergence between Adriatic and European populations, albeit with some discordance between the mtDNA phylogeny of the northern Adriatic populations, further highlighting the strong differentiation among the Adriatic populations. The southern populations within the Adriatic lineage were further organized into distinct clades corresponding to respective river catchments and sub-clades corresponding to river tributaries, reflecting a high degree of population structuring within a small geographic region, concurrent with suggestions of existence of several microrefugia within the Balkan Peninsula. The highly divergent clades and haplotypes unique to the southern Adriatic populations further suggest, in accordance with an earlier, more limited survey, that southern Adriatic populations represent an important reservoir for ancient genetic diversity of G. aculeatus.

Phylogeography and Conservation Genetics of the Ibero-Balearic Three-Spined Stickleback (Gasterosteus aculeatus)

“…The phylogenetic network obtained after adding published sequences [17, 20, 24, 49–54] to our cytb dataset confirmed the differentiation of the Adriatic basins of Skadar and Neretva, raised as distinct conservation units [60], as well as the basal position of haplotypes H106 and H109 (SprSka2_A and SprSka5_A according to DeFaveri et al [52]) both from Skadar. As many as seven star-like groups of haplotypes can be readily distinguished: those ones around H1, H3, H4, H8, H19, H36 and H41.…”

FIRST RECORD OF THREE-SPINED STICKLEBACK (Gasterosteus aculeatus Linnaeus, 1758) IN THE DANUBE BASIN OF CROATIA

“…In the IUCN Red List of freshwater fishes, G. gymnurus is listed as a species of Least Concern (LC) and in the Catalog of Fishes of the California Academy of Sciences (Eschmeyer, 2015), G. gymnurus is listed as a valid name. However, Foster et al (2003) stated that all freshwater populations were derived from common marine ancestor which was complete or high-plated morph and the results of Zanella et al (2015) complement the earlier genetic DeFaveri et al, 2012) and phenotypic (Cano et al, 2008;Zanella, 2009) surveys of Adriatic stickleback populations, demonstrating widespread and substantial ecologically driven phenotypic differentiation independent of neutral genetic differentiation, suggesting that the populations of the three-spined sticklebacks of Europe form part of the species complex G. aculeatus.…”

“…Sticklebakcs are also recorded in Danube drainage in Serbia (Cakić et al, 2000;Šipoš et al, 2007) and in Hungary in Drava River (Csipkés et al, 2012). The nearest finding recorded is near the villages of Bunčani and Veržej in Slovenia, approximately 15 km upstream from the Croatian-Slovenian border and 30 km from this site (DeFaveri et al, 2012). It is considered that this Slovenian population is allochthonous (Govedič, 2012) and may have been derived from populations released near Vienna about 130 years ago, very likely by aquarists (Ahnelt et al, 1998;Zanella, 2009).…”

“…it had less than 10 lateral plates. Sticklebacks are known to inhabit the Mura River in Slovenia and Austria (Povž and Sket, 1990;Zulka, 2006;DeFaveri et al, 2012;Govedič, 2012) where all three typical morphs (complete, partial and low) were found (Zanella, 2009). Sticklebakcs are also recorded in Danube drainage in Serbia (Cakić et al, 2000;Šipoš et al, 2007) and in Hungary in Drava River (Csipkés et al, 2012).…”

“…Croatian populations have been categorised as endangered (EN) (Mrakovčić et al, 2006). The ability to adapt rapidly to new environmental conditions makes the three-spined stickleback a suitable model for numerous evolutionary studies (DeFaveri et al, 2012). Over millions of years, this taxon experienced numerous freshwater habitat colonization events that resulted in repeated and independent adaptive radiation from an oceanic ancestor (Clavero et al, 2009).…”