Molecular and ecological features of the soft-muzzled trout Salmo obtusirostris (Heckel, 1852) in the Zeta River, Montenegro

Abstract

This paper reports about the occurrence of soft-muzzled trout in Montenegro. It was found only in the Zeta River, at three localities, always in low abundance. Results of genetic investigation on twelve microsatellite loci (i.e., high Fst and high heterozygozity values) as well as lack of hybridization with the putative brown trout unequivocally confirm that the soft-muzzled trout from the Zeta River is a species distinct from the putative brown (Salmo cf. farioides) and marble (Salmo marmoratus) trout that live in sympatry with it. This paper also confirms high genetic diversity of Zeta River soft -muzzled trout population. Habitat and feeding analyses revealed that soft-muzzled trout reduce the competition with syntopic putative brown trout by displacing as the bottom-dweller in their common type of habitat, as well as by narrowing its feeding niche and feeding dominantly with the benthic macroinvertebrates, the Gammarus shrimps as their far dominant feeding item. Results also revealed that they did not share the same habitat with marble trout. Due to this population low abundance and their importance on species level, Zeta River soft-muzzled trout conservation needs are urgent in terms of in situ protection and repopulation measures.

Risk screening of non‐native freshwater fishes in Croatia and Slovenia using the Fish Invasiveness Screening Kit

“…; Mrdak et al . ). Supportive evidence for this can be found in the River Danube basin, that is introgression of alien At1 haplotype of sea trout (Marić et al .…”

“…Population-specific microsatellite allele profiles indicate hybridisation between brown trout of Atlantic lineage and Jadro softmouth trout, pointing to a likely ancient origin ). This has raised concerns that introductions of brown trout of Atlantic and Danube linage into the river catchment may be leading to the extinction of trout species endemic to the River Jadro but also to the Adriatic basin (Snoj et al 2008;Mrdak et al 2012). Supportive evidence for this can be found in the River Danube basin, that is introgression of alien At1 haplotype of sea trout (Mari c et al 2006(Mari c et al , 2010(Mari c et al , 2012, which caused the loss of intraspecific variability after the introduction of non-native strains and a change in genetic composition of native brown trout stock of Danube lineage (Horv ath et al 2014;Simonovi c et al 2014).…”

Alien freshwater fish species in the Balkans—Vectors and pathways of introduction

“…Recent surveys from several Balkan countries, however, have revealed that 15%–23% of their fish fauna is alien (Barbieri et al., ; Piria, Tomljanović et al., ; Piria, Povž et al., ; Simonović et al., ), with certain catchments, such as the Danube River and Pamvotis Lake (Greece), having an ichthyofauna comprised of more than 50% and 80% of alien fishes, respectively (Leonardos, Kagalou, Tsoumani, & Economidis, ; Simonović et al., ). Furthermore, owing to the high level of endemism and the great conservational value of the Balkan freshwater fish species, introductions can have severe negative and irreversible impacts on the ichthyodiversity of the Peninsula (Barbieri et al., ; Ćaleta et al., ; Karapetkova & Zhivkov, ; Mrdak, Nikolić, Tošić, & Simonović, ; Povž, Gregori, & Gregori, ; Snoj, Razpet, Tomljanović, Treer, & Sušnik, ; Sušnik et al., ). Although there is national legislation in place that regulates fish and other alien species introductions in the Balkans (Piria et al., ), and elsewhere in Europe (Copp et al., ), this legislation is rarely enforced by national environmental agencies and are practically ineffective.…”

“…Population‐specific microsatellite allele profiles indicate hybridization between brown trout of Atlantic lineage and Jadro softmouth trout (Sušnik et al., ). This has raised concerns that introductions of brown trout of Atlantic and Danube linages into the Adriatic basin catchment may lead to the extinction of endemic trout species (Mrdak et al., ; Snoj, Bogut, & Sušnik, ). Supportive evidence for this can be found in the Danube River basin, that is introgression of alien At1 haplotype of Atlantic brown trout (Marić, Sušnik, Simonović, & Snoj, ), which caused the loss of intraspecific variability, following the introduction of alien strains and a change in genetic composition of native brown trout stock of Danube lineage (Simonović et al., ).…”

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“…Molecular markers, such as mtDNA D-loop and cytochrome b, microsatellites, RFLP (Restriction Fagments Length Polymorphism) and AFLP (Amplified Fragments Length Polymorphism), were recently used in a variety of investigations regarding brown trout. These include evolutionary and population-genetic studies (Zhang and Hewitt, 2003), phylogeography (Bernatchez, 2001;Cortey et al, 2002Cortey et al, , 2004, effects of stocking, conservation and management of populations and species (Apostolidis et al, 2008;Vera et al, 2010b;Kohout, 2012Kohout, , 2013, identification of migrating strains (Habibi et al, 2013) and resolving of the taxonomy-regarding confusion (Apostolidis et al, 2011;Mrdak et al, 2012). Mitochondrial DNA (mtDNA) has a number of characteristics that makes it a valuable molecular marker for evolutionary and population-genetic structure studies (Zhang and Hewitt, 2003).…”