New data on sterlet (Acipenser ruthenus L.) genetic diversity in the middle and Lower Danube sections, based on mitochondrial DNA analyses

Abstract

Poor regulated fishery, pollution, fragmentation and loss of habitat are most important factors influencing decline of sterlet population worldwide. In Middle and Lower Danube region, this species still have significant economic importance since wilde populations are commercially exploited, while Upper Danube populations are dependent on stocking efforts in order to maintain their presence in open waters. Aim of present study is to analyze genetic diversity of sterlet populations from the Middle and Lower Danube and Lower Tisza rivers, as a prerequisite for their effective conservation and management. Analysis of a highly variable D-loop fragment of mitochondrial DNA detected five new haplotypes, while the eight previously identified haplotypes had extended their previous range. Genetic variability could be attributed almost entirely to individuals, with observed lack of population structure. Negative values of neutrality test indicate recent expansion on some sampling locations. Adittionaly, gene flow analysis between Lower and Middle Danube region showed intensive exchange of speciemens. At the same time analysis showed some influence of Tisza dam on gene flow between samples from Tisza and Middle Danube section.Our study indicated the need for a careful planning of sterlet stocking programmes and inclusion of demographic data or catch time-series. [Projekat Ministarstva nauke Republike Srbije, br. 173045]

Current stocking program of the sterlet (Acipenser ruthenus, L.) can negatively shape its genetic variability in the Middle Danube

“…Overall, the recovered mitochondrial diversity of sterlet population in the Middle Danube (Slovak-Hungarian stretch) is comparable with other parts of the river (e.g. Reinartz et al, 2011;Cvijanović et al, 2015), but within three groups, particularly for the more variable CYTB, a notable difference in the number of haplotypes was observed (W À 8, F1 -5, S À 2). Although with almost the lowest size, the WILD group had the highest number of haplotypes.…”

“…The genetic data acquired within recent studies (e.g. Cvijanović et al, 2015;Fopp-Bayat et al, 2015;Chassaing et al, 2016) clearly show that well-managed and urgent actions are needed if we want to prevent their extinction. Among other actions including the restoration of key habitats and reopening of closed migrations routes, a wellmanaged stocking program is needed.…”

Past and Future of Sturgeon Species (Acipenseridae) in Western Balkans: Case for Permanent Conservation or Sustainable Management

“…Based on available data, during the mid-twentieth century, research of sturgeons in the Western Balkans was oriented to life history, biology, and ecology (Janković 1958;Ristić 1963aRistić , b, c, 1967aRistić , b, c, d, 1969a. Due to lack of different sturgeons species, as a consequence of Iron Gate dams construction, as well as lack of funding, later research was focused on sterlet morphometry, pollution assessment, and genetic (Jarić et al 2011c;Lenhardt et al 2012Lenhardt et al , 2014Cvijanović et al 2015Cvijanović et al , 2017, i.e., more laboratory-oriented research. In the last decade, development of population models and extinction models (Jarić et al 2009a(Jarić et al , 2010(Jarić et al , 2014(Jarić et al , 2016Simić et al 2014) provided tools for decision makers to adapt conservation measures.…”

“…At the beginning of the twenty-first century, number of publications concerning sturgeons and their protection in Western Balkans rapidly increased (Lenhardt et al 2004(Lenhardt et al , 2005a(Lenhardt et al , 2006a(Lenhardt et al , 2009(Lenhardt et al , 2012(Lenhardt et al , 2014Jarić et al 2009aJarić et al , b, 2010Jarić et al , 2011aJarić et al , b, c, 2014Jarić et al , 2015Smederevac-Lalić et al 2011;Cvijanović et al 2015Cvijanović et al , 2017. Although beluga, Russian sturgeon, Atlantic sturgeon, and ship sturgeon are investigated (Lenhardt et al 2005a(Lenhardt et al , 2006aJarić et al 2009bJarić et al , 2011a, main focus was on sterlet (Lenhardt et al 2004(Lenhardt et al , 2009(Lenhardt et al , 2012Ognjanović et al 2008, Jarić et al 2011cCvijanović et al 2015Cvijanović et al , 2017, with nonindigenous paddlefish (Polyodon spathula) and Siberian sturgeon (Acipenser baerii) also subject of interest (Lenhardt et al 2006b;Jarić et al 2019;Govedič and Friedrich 2018). Sterlet survey in the Danube River, between 2002-2003 (Lenhardt et al 2004) showed shift of length-frequency distribution toward lower length classes, as well as decrease in sterlet catch.…”

“…Input parameters required to apply the presented approach include female fecundity, age at maturity, longevity, adult, subadult and YOY survival, and spawning frequency. During 2007-2009, wild starlet populations, from Middle and Lower Danube and Lower Tisza rivers, were investigated (Cvijanović et al 2015;Cvijanović et al 2017) for genetic diversity with the use of mtDNA and microsatellite loci. These analyses showed variation in the detection of a genetic bottleneck, as well as revealing different effective population size.…”