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The use of translocations to establish new or ‘refuge’ populations for species with high conservation value is controversial but widely used in conservation management. One of the risks of this approach is that an establishing population does not adequately capture the genetic diversity of the donor gene pool. This effect, rarely examined, is tested here. In this study the genetic consequences of two conservation translocations after five generations (16 years) of the European whitefish, Coregonus lavaretus, were quantified. Both translocations were made using almost the same genetic groups and thus represent a partly replicated natural study. Analysis of 12 informative microsatellites showed that expected heterozygosity, the mean number of alleles per locus and allelic richness did not differ between donor and translocated populations. There was also no loss of heterozygosity in the translocated populations, nor deviations from Hardy–Weinberg equilibrium expectations, nor signs of linkage disequilibrium. All populations were genetically differentiated but pairwise FST values were low, indicating that the magnitude of divergence was small. There was no evidence of inbreeding but there were significant differences in private allelic richness between donor and translocated populations. Of 50 alleles found in the donor population, 16% of the rarer alleles were lost in one translocated population and 8% in the other. Allele loss without a reduction in heterozygosity strongly points to stochastic drift effects having occurred following translocation. The evidence indicates that alleles that were not detected in the donor population have arisen de novo in the translocated populations. It is concluded that conservation translocations comprising even a modest number of propagules can successfully capture a high proportion of genetic variation of the host population, and that reduced genetic variation in the translocated population may be mitigated by the emergence of new variation over short time periods.

The European whitefish Coregonus lavaretus complex represents one of the most diverse radiations within salmonids, with extreme morphological and genetic differentiation across its range. Such variation has led to the assignment of many populations to separate species. In Great Britain, the seven native populations of C. lavaretus (two in Scotland, four in England, one in Wales) were previously classified into three species, and recent taxonomic revision resurrected the previous nomenclature. Here we used a dataset of 15 microsatellites to: (1) investigate the genetic diversity of British populations, (2) assess the level of population structure and the relationships between British populations. Genetic diversity was highest in Welsh (HO = 0.50, AR = 5.29), intermediate in English (HO = 0.41–0.50, AR = 2.83–3.88), and lowest in Scottish populations (HO = 0.28–0.35, AR = 2.56–3.04). Population structure analyses indicated high genetic differentiation (global FST = 0.388) between all populations but for the two Scottish populations (FST = 0.063) and two English populations (FST = 0.038). Principal component analysis and molecular ANOVA revealed separation between Scottish, English, and Welsh populations, with the Scottish populations being the most diverged. We argue that the data presented here are not sufficient to support a separation of the British European whitefish populations into three separate species, but support the delineation of different ESUs for these populations.

The use of translocations to establish new or ‘refuge’ populations for species with high conservation value is a controversial, but widely used, technique in conservation management. Two of the risks of this approach are that a new population will fail to establish, or that, if it does establish, it will fail to adequately capture the genetic diversity of the donor gene pool. This latter effect has however, been rarely tested. In this study we quantify the genetic consequences of two conservation translocations after five generations (16 years) of the European whitefish, Coregonus lavaretus, which is rare in the UK. Both translocations were made using almost the same genetic groups and thus represent a partly replicated natural study. Analysis of 12 informative microsatellites showed that expected heterozygosity, the mean number of alleles per locus and allelic richness did not differ between donor and translocated populations and there also was also no loss of heterozygosity in the translocated populations, nor deviations from expectation under the Hardy-Weinberg equilibrium, nor signs of linkage disequilibrium. There was clear and statistically robust evidence that all populations were genetically differentiated but the FST values were low, indicating that the magnitude of divergence was small. There was no evidence of inbreeding but there were significant differences in private allelic richness between donor and translocated populations. Of the 50 alleles found in the donor population 16% of the rarer alleles were lost in one translocated population and 8% in the other. The loss of alleles without a reduction in heterozygosity strongly points to stochastic drift effects having occurred following the translocation. However, surprisingly, both translocation populations showed evidence of having accumulated new, but different, alleles. Several strands of evidence suggest this this is not because these alleles were not detected in the donor population but because they have arisen de novo in the translocated populations.

The whitefish (Coregonus lavaretus (L.)) is of high biodiversity value in the U.K., where it exists as a total of only seven native populations in England (Brotherswater, Haweswater, Red Tarn and Ullswater), Scotland (Loch Eck and Loch Lomond) and Wales (Llyn Tegid also known as Bala Lake), and is protected by national conservation legislation. However, an absence of fisheries means that information on its populations is scarce and must be obtained by dedicated surveys and associated activities. A standardised national assessment protocol using hydroacoustics and survey gill netting is described and results are presented from its use on the three whitefish populations of Scotland and Wales. For the remaining four English populations where the assessment protocol has not yet been specifically applied, comparable data are available from similar surveys, augmented by long-term fish entrapment records at one lake. These surveys revealed that the whitefish populations of Loch Eck, Red Tarn and Ullswater were in favourable condition. However, the condition of whitefish in Brotherswater, Haweswater, Llyn Tegid and Loch Lomond was considered to be unfavourable. Conservation measures specific to the whitefish populations of greatest concern in Haweswater, Llyn Tegid and Loch Lomond are described, including the management of water levels, local control of nesting cormorants (Phalacrocorax carbo (L.)) and establishment of refuge populations.

Although also formerly present in two lochs in South West Scotland, populations of vendace (Coregonus albula) were until recently believed to persist in only two U.K. lakes, i.e., Bassenthwaite Lake and Derwent Water in North West England. However, although Derwent Water has retained its natural mesotrophic conditions and the status of its vendace population is acceptable, monitoring at Bassenthwaite Lake has failed to record any specimens since 2000 and the species has recently been declared locally extinct. Bassenthwaite Lake has experienced increasing problems from eutrophication, sedimentation and the introduction of fi sh species including roach (Rutilus rutilus) and ruffe (Gymnocephalus cernuus), both of which have more recently also been introduced to Derwent Water and give concern over possible food competition and egg predation. In addition to monitoring, considerable efforts have been made in recent years to conserve vendace through the protection and improvement of their habitats and the establishment of refuge populations. The latter has resulted in the establishment of a population originating from Bassenthwaite Lake in Loch Skeen of South West Scotland, with further attempts still in progress at two other sites. Public awareness of the conservation of this species, which is the U.K.'s rarest freshwater fish, has also been actively promoted.