Distribution of non-native trout in Slovenia and their introgression with native trout populations as observed through microsatellite DNA analysis

Jug, Tjaša; Berrebi, Patrick; Snoj, Aleš

doi:10.1016/j.biocon.2004.11.022

Cited by 57 publications

(35 citation statements)

References 27 publications

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“…Since 1900, however, massive introductions and repeated stocking with allochthonous brown trout of the AT lineage have severely affected the genetic integrity of many marble trout populations (Giuffra et al 1996;Delling et al 2000;Jug et al 2005). In the western part of the Po River system (northern Italy), introgression rates of up to 70% with domesticated hatchery-reared strains were described (Giuffra et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Microsatellite DNA data point to extensive but incomplete admixture in a marble and brown trout hybridisation zone

et al. 2009

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Marble trout, endemic to the Adriatic drainage basin, is severely threatened by hybridisation with nonnative brown trout. In the present study, we analysed 12 microsatellite DNA loci to assess genetic population structure and differentiation between sympatric phenotypic marble and brown trout at nine sampling sites in the upper Etsch/Adige River system. F ST and AMOVA analyses revealed significant genetic differentiation between marble and brown trout samples. Thus, admixture between brown and marble trout appears to be incomplete. However, factorial correspondence analysis depicted marble trout, Atlantic brown trout and intermediate genotypes. Bayesian-based individual assignment tests identified indigenous marble trout at five sampling sites. In four other samples no 'pure' marble trout were detected. Bidirectional, first-generation hybridisation, involving both sexes of both parental species was observed. In locations where 'pure' marble trout still exist, post-F1 hybridisation appears to be directed towards brown trout. This has likely slowed the rate of hybridisation between the two trout species and the decline of relic marble trout populations. Based on these results, restoration management actions are proposed, such as the abandonment of brown trout stocking activities, sharper angling policies, establishment of indigenous marble trout breeding strains and the elaboration of a conservation priority list.

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Section: Introductionmentioning

confidence: 99%

Microsatellite DNA data point to extensive but incomplete admixture in a marble and brown trout hybridisation zone

et al. 2009

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“…1 Allele frequency distribution for softmouth trout from the Jadro river (black blocks) and Ž rnovnica (white blocks) at 15 microsatellite loci. Blocks marked with asterisks represent alleles found only in hybrid animals Jug et al 2005). The recent bottlenecks however, were not detected within the two populations, despite the fact that the number of generations after the translocation (12) fell within the interval (0.25-2.5 times 2N e ; Cornuet and Luikart 1996) having the highest power at detecting the bottleneck in Ž rnovnica population.…”

Section: Discussionmentioning

confidence: 97%

Genetic composition of the Jadro softmouth trout following translocation into a new habitat

et al. 2006

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Genetic founder effects of a historical translocation (1965; app. 12 generations ago) of endangered softmouth trout from the only remaining indigenous population to an adjacent uninhabited river were investigated. A comparison of 15 microsatellites from contemporary samples in both the source and re-established populations indicated a very low level of genetic diversity within the two populations. Furthermore, considerable differences in estimates of variability and effective population sizes were detected between populations, but no recent bottlenecks were evident. Our data suggest that the re-established population has lost variation due to genetic drift associated with founder effects following the translocation. Accordingly, in relation to management, we suggest that the re-established population could serve as a secondary source of individuals to buffer possible extinction due to demographic events. Finally, conservation initiatives to enhance the census population size and increase levels of variability in the re-established population are proposed.

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“…Fumagalli et al (2002) reported that its populations have critically declined due to introgression of brown trout strains. Introgression with hatchery-reared fish is a common threat to salmonids for which significant levels of gene flow from stocked strains into wild populations have been shown (Delling et al 2000;Fumagalli et al 2002;Jug et al 2005). Atlantic mitochondrial DNA lineages have been identified that severely affected the genetic integrity of marble trout populations (Delling et al 2000;Jug et al 2005).…”

Section: Discussionmentioning

confidence: 99%

“…Introgression with hatchery-reared fish is a common threat to salmonids for which significant levels of gene flow from stocked strains into wild populations have been shown (Delling et al 2000;Fumagalli et al 2002;Jug et al 2005). Atlantic mitochondrial DNA lineages have been identified that severely affected the genetic integrity of marble trout populations (Delling et al 2000;Jug et al 2005). Hybridization between marble and brown trout has been so extensive that morphologically typical marmoratus forms are very rare nowadays and the species is considered one of the most endangered freshwater fish in the Adriatic basin (Povž 1995;Delling et al 2000).…”

Section: Discussionmentioning

confidence: 99%

Historical impacts of mercury mining and stocking of non-native fish on ichthyofauna in the Idrijca River Basin, Slovenia

Torkar

Zwitter

2015

Aquat Sci

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Mercury mining in Idrija has profoundly changed environmental conditions in the Idrijca River basin. Impacts of mining-related activities on the river system and its ichthyofauna from circa 1490 until World War I were analysed. Literature and archival sources were both studied. Heavy water pollution with mercury and its components, the floating of wood using splash dams in order to create artificial flood waves, fishing and stocking of non-indigenous fish species were the factors identified contributing to major impacts on ichthyofauna. Fish statistics make clear that after four centuries of mercury production ichthyofauna in the Idrijca was by no means the most industrially affected one in Carniola and that there were huge differences among various sections of the Idrijca and its tributaries. We presented the history of fish hatcheries operating from 1876 onward in order to reduce the damage inflicted by mercury mining and related activities and reviewed its impacts on hybridization between marble and brown trout. Introduction of non-native fish was the major threat for the ichthyofauna in comparison to the other mentioned impacts of mercury mining, conducted over long periods but with comparably minor consequences for the survival of the native ichthyofauna.

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Distribution of non-native trout in Slovenia and their introgression with native trout populations as observed through microsatellite DNA analysis

Cited by 57 publications

References 27 publications

Microsatellite DNA data point to extensive but incomplete admixture in a marble and brown trout hybridisation zone

Microsatellite DNA data point to extensive but incomplete admixture in a marble and brown trout hybridisation zone

Genetic composition of the Jadro softmouth trout following translocation into a new habitat

Historical impacts of mercury mining and stocking of non-native fish on ichthyofauna in the Idrijca River Basin, Slovenia

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