Abstract
Diversity of native trout fish Salmo spp. comprises a variety of nominal taxa in Serbia, Montenegro and Bosnia and Herzegovina. Recent mapping of the resident trout detected brown trout S. trutta (sensu stricto) of the Atlantic (AT) mtDNA lineage introduced into populations of both tentative Danubian trout S. labrax and of tentative Adriatic trout S. farioides belonging to the Danubian (DA) and Adriatic (AD) mtDNA lineages, respectively. In addition, an introduction of the tentative Macedonian trout S. macedonicus of the AD lineage was detected in the one native population of the tentative S. labrax. In almost all recipient non-migratory trout populations, a cross breeding between the native and introduced trout was detected by heterozygosity in either only LDH-C nuclear locus, or in LDH-C and particular microsatellites’ loci. Exception is one population where both resident and migratory, lake-dwelling individuals of the tentative Adriatic trout spawned at the downstream section of a stream in Montenegro, none of microsatellites’ alleles of Atlantic brown trout that were introduced into the upstream section was detected. The occurrence of cross breeding between Adriatic and brown trout was evident in the upstream, isolated section. It seems that migrating, lake-dwelling Adriatic trout in combination with their resident, stream-dwelling conspecifics suppress introgression of genes from those situated upstream, strongly introgressed by brown trout. Having this in sight, it is noteworthy to warn on the occurrence of the migratory brown trout in the Danube River at the broader Iron Gate Gorge area. They were recorded to migrate in late summer and early fall from the Iron Gate One reservoir to the lower sections of tributaries devoid of any trout fish. However, some of those streams home very special native trout of the DA lineage in their short-extending upper sections. Those native trout populations are so far still out of contact with the reservoir-dwelling trout. However, having in mind the resilience of trout featuring the migratory life-history, the outcome of this introduction could be deleterious for those natives very precious in conservational sense.
Highlights
Some 25 nominal trout Salmo spp. taxa have been described throughout the dispersal area of this complex species (Kottelat, 1997)
In the streams feeding the middle course of the Una River, where the native brown trout belongs to the Da22 haplotype (GenBank accession number AF321993; Duftner et al, 2003), three out of 10 brown trout from the Krušnica River (33%) and three out of 10 from the Svetinja River (33%) belonged to the Atcs1 haplotype (#AF321990; Weiss et al, 2001; Škraba et al, 2017)
In all streams in the Iron Gate Gorge area, brown trout of the AT haplogroup were recorded in the Brnjica River, Dobra River, and Porecka River and in the Danube River near the confluence with the Dobra River, while in the Vratna River, they were found in sympatry with the brown trout of the Da23c haplotype (#KC630984; Tošicet al., 2014), [i.e., three of 10 (33%) brown trout in total were of this haplotype (Tošicet al., 2016)]
Summary
Some 25 nominal trout Salmo spp. taxa have been described throughout the dispersal area of this complex species (Kottelat, 1997). This illustrates the great variety in their traits, and introduces confusion in their taxonomy from the conceptual point of view. Whiteley et al (2019) stated that the current taxonomic richness within the S. trutta was promoted by Kottelat (1997), who followed the evolutionary species concept of Simpson (1961) to assign local brown trout subspecies originally described on the basis of slight differences in a limited number of traits between local populations as nominal species (Kottelat and Freyhof, 2007). Taler’s trout Salmo taleri (Karaman, 1933) and Danubian salmon Salmo labrax (Pallas, 1814), tentatively occur in the Black Sea Basin, while the Macedonian trout Salmo macedonicus (Karaman, 1924) and Pelagonian trout Salmo pelagonicus (Karaman, 1938), are found in the Vardar River (Axios) and Struma River (Strymon) in the Aegean Sea Basin
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
