Haplotype diversity of brown trout Salmo trutta (L.) in the broader Iron Gate area

Abstract

Mitochondrial DNA (mtDNA) haplotypes of brown trout (Salmo trutta L.) populations in the area of Djerdap National Park were analyzed in order to determine their phylogeographic statuses. Sequencing the control region of mtDNA in 66 specimens from 9 streams in the broader Iron Gate area revealed that 7 brown trout from those streams carried haplotypes of Atlantic lineage,while the remaining 59 fish were of Danubian lineage,either of Da23c or Da1 haplotypes. Four streams were inhabited by populations of the indigenous Da23c mtDNA haplotype,while the population in one stream had the Da1 haplotype. In the remaining 4 streams,brown trout of exclusively Atlantic lineage were present in 3,while those of the Da23c haplotype were additionally present in the fourth. The significant fixation index Fst in all populations,caused by a significantly large proportion of the among-population component of variance,revealed the fixation of particular haplotypes in the majority of populations. The size of a particular stream determines native brown trout abundance and limits their suitability for restorative purposes.