Coregonus peled (Gmelin) transplanted into Ulaagchny Khar lake (western mongolia) showed no evidence of hybridization with other introduced Coregonus species

Resumo

Coregonus peled (Gmelin) (Teleostei: Salmoniformes: Coregonidae), which is considered an important object of coldwater aquaculture, had been successfully introduced into an enclosed Western Mongolian lake Ulaagchny Khar in the early 1980s. At the same time larvae of two other Coregonus species—Baikal omul C. migratorius (Georgi) and least cisco C. sardinella Valenciennes—had also been released into the lake. Baikal omul was then reported as a naturalized species. This might have caused interspecific hybridization and gene introgression. Identification of coregonids by morphology can be problematic, so to determine which species was dominant in the lake (we presumed it was peled) and if its gene pool was affected by other introduced Coregonus species we sampled 40 individuals and analyzed them by sequencing a fragment of mtDNA cyt b and by allozyme electrophoresis. The analysis showed that all the fish belonged to C. peled with no evidence of admixture from other coregonid species. Taking into account mass release of both species in 1980s, it is evident that naturalization of peled in the lake was much more successful than that of Baikal omul.