Multiple stocks of whitefish (Coregonus lavaretus (L.) complex) in the pre-alpine lake Traunsee: recommendations for habitat-specific conservation units
Winkler, Kathrin A.; Weiss, Steven; Pamminger-Lahnsteiner, Barbara; Wanzenböck, Josef
Defining conservation units for taxa with complex within and among population structure is challenging. Whitefish (Coregonus lavaretus (L.) complex) have diverged post-glacially within single lakes to exhibit differences in morphology, feeding ecology, habitat use and spawning. Austrian prealpine whitefish have also been exposed to introductions of stocks of Baltic origin. We evaluate the genetic structure of Coregonus in the Austrian pre-alpine lake Traunsee by sampling larvae from 12 sites throughout the lake and then using Bayesian clustering as well as multivariate approaches. Multiple genetic clusters of the native lineage were detected, albeit with no apparent spatial structure. Cluster recognition was supported by highly significant GST and DEST values. The lake primarily harbours native genotypes as only a few individuals of the introduced lineage could be found with little to no sign of introgression. The significant genetic structure of the native gene pool in Traunsee may be related to the existence of a deep-dwelling dwarf taxon, Coregonus danneri Vogt, living in sympatry with the more broadly distributed Coregonus renke (Paula-Schrank). Most likely this is the last population of C. danneri in Austria and we urge that it should be protected from environmental perturbation. We additionally recommend that C. renke, though broadly distributed, not be managed as an exchangeable taxon between lakes with and without C. danneri.