One Fish, Two Fish, Old Fish, New Fish-Is the Biodiversity of Bulgarian Native Brown Trout (S. Trutta Fario) Populations at Risk?

Human impact on genetic variability of species is a prominent cause for loss of biodiversity on a global scale. The present work offers evidence that the genetic diversity in Bulgarian native populations of brown trout is already failing because of alteration of the population structure via enhanced human-mediated assortative mating and/or interspecies hybridisation with other salmonids. The risk of adverse genetic consequences to the native populations is already significant. Bulgarian aquaculture may benefit from more strict control policy over stock transfer and release offish and stock material into the natural water basins.