Baltic Populations Research Articles

Metabolic rate and activity of blue mussel Mytilus edulis trossulus under short-term exposure to carbon dioxide-induced water acidification and oxygen deficiency

This work investigated the effect of carbon dioxide-induced decreased water pH (8.1 – control, 7.5 and 7.0), oxygen saturation (~100% and ~20%) and the combination of both factors on the behaviour (gaping activity) and the total metabolic rate of blue mussel Mytilus edulis trossulus from the southern Baltic Sea. Heat dissipation measurements were carried out in a Calvet-type isothermal twin calorimeter equipped with a flow-through system. The resting metabolic rate was not significantly (p > 0.05) affected by pH or oxygen saturation. Neither was there significant (p > 0.05) effect of the interaction of both factors on this process. The high inter-individual variability in behaviour affected the value of maximal recorded activity and duration of activity peaks connected with shell gaping behaviour. In some mussels, they were short and appeared periodically, and other individuals were inactive or exhibited temporal activity terms of different duration. The lowered oxygen saturation significantly (p < 0.05) affected the time spent on activity. However, there was no effect (p > 0.05) of lowered pH on this parameter, which indicates that oxygen deficiency may affect the Baltic population of M. edulis trossulus more seriously than acidification.

Differences in the metabolic response to temperature acclimation in nine-spined stickleback (Pungitius pungitius) populations from contrasting thermal environments.

Metabolic responses to temperature changes are crucial for maintaining the energy balance of an individual under seasonal temperature fluctuations. To understand how such responses differ in recently isolated populations (<11,000 years), we studied four Baltic populations of the nine-spined stickleback (Pungitius pungitius L.) from coastal locations (seasonal temperature range, 0-29°C) and from colder, more thermally stable spring-fed ponds (1-19°C). Salinity and predation pressure also differed between these locations. We acclimatized wild-caught fish to 6, 11, and 19°C in common garden conditions for 4-6 months and determined their aerobic scope and hepatosomatic index (HSI). The freshwater fish from the colder (2-14°C), predator-free pond population exhibited complete temperature compensation for their aerobic scope, whereas the coastal populations underwent metabolic rate reduction during the cold treatment. Coastal populations had higher HSI than the colder pond population at all temperatures, with cold acclimation accentuating this effect. The metabolic rates and HSI for freshwater fish from the pond with higher predation pressure were more similar to those of the coastal ones. Our results suggest that ontogenic effects and/or genetic differentiation are responsible for differential energy storage and metabolic responses between these populations. This work demonstrates the metabolic versatility of the nine-spined stickleback and the pertinence of an energetic framework to better understand potential local adaptations. It also demonstrates that instead of using a single acclimation temperature thermal reaction norms should be compared when studying individuals originating from different thermal environments in a common garden setting.

Infraspecific diversity in a spore-dispersed species with limited distribution range

Infraspecific genetic diversity is generally underestimated in biodiversity assessments. We use haplotype patterns based on the nuclear gpd and plastid rpl16 to examine whether genetic diversity is related to geography, gender, habitat and/or frequency of sexual reproduction in Drepanocladus lycopodioides. This moss is restricted to western Eurasian semi-natural and natural habitats and decreases in frequency in many parts of Europe. Haplotype diversity differs among three regional populations (Öland, Gotland, Stockholm archipelago) in its South Swedish Baltic core distribution area and is positively affected by patch size. The regional populations differ from each other genetically and haplotype variation is unequally partitioned between the genders, most likely a result of immigration history and limited equalizing effects of sexual reproduction. In a Holocene context, the regional populations of Öland and Gotland display evidence of a decrease or bottleneck, and immigration into both regions. We suggest that higher haplotype diversity in Gotland and Öland and lack of migration to the Stockholm archipelago may be an effect of longer colonization history of the former, and niche pre-emption in the natural habitats of the latter. The Baltic population is representative for the genetically relatively homogeneous European population, and D. lycopodioides displays low ITS variation compared with other European mosses. In a conservation context it is relevant that the three regional populations are not interchangeable. It is of concern that three populations within the species’ core distribution are vulnerable. Our results strongly suggest that infraspecific genetic diversity must be considered in the management of the species at the continental level.

Mapping present and future potential distribution patterns for a meso-grazer guild in the Baltic Sea.

AimThe Baltic Sea is one of the world's largest semi-enclosed brackish water bodies characterized by many special features, including endemic species that may be particularly threatened by climate change. We mapped potential distribution patterns under present and future conditions for a community with three trophic levels. We analysed climate-induced changes in the species' distribution patterns and examined possible consequences for the chosen food web.LocationBaltic Sea and northern Europe.MethodsWe developed two open-source workflow-based analytical tools: one for ecological niche modelling and another for raster layer comparison to compute the extent and intensity of change in species' potential distributions. Individual ecological niche models were generated under present conditions and then projected into a future climate change scenario (2050) for a food web consisting of a guild of meso-grazers (Idotea spp.), their host algae (Fucus vesiculosus and Fucus radicans) and their fish predator (Gasterosteus aculeatus). We used occurrence data from the Global Biodiversity Information Facility (GBIF), literature and museum collections, together with five environmental layers at a resolution of 5 and 30 arc-minutes.ResultsHabitat suitability for Idotea balthica and Idotea chelipes in the Baltic Sea seems to be mostly determined by temperature and ice cover rather than by salinity. 2050 predictions for all modelled species show a northern/north-eastern shift in the Baltic Sea. The distribution ranges for Idotea granulosa and G. aculeatus are predicted to become patchier in the Baltic than in the rest of northern Europe, where the species will gain more suitable habitats.Main conclusionsFor the Baltic Sea, climate-induced changes resulted in a gain of suitable habitats for F. vesiculosus,I. chelipes and I. balthica, whereas lower habitat suitability was predicted for I. granulosa,F. radicans and G. aculeatus. The predicted north-eastern shift of I. balthica and I. chelipes into the distribution area of F. radicans in the Baltic Sea may result in increased grazing pressure. Such additional threats to isolated Baltic populations can lead to a higher extinction risk for the species, especially as climate changes are likely to be very rapid.

Comparative study of ecophysiological and biochemical variation between the Baltic and North Sea populations of the invasive soft shell clam Mya arenaria (L. 1758)

Abstract Seasonal variations of environmental factors, such as temperature and salinity, require metabolic acclimatization in sedentary benthic fauna distributed over a wide geographical range. The soft-shell clam Mya arenaria inhabits the coastal waters of the North Atlantic including North America and Europe. In Europe, M. arenaria populations are distributed from Iceland to the Mediterranean Sea, including the North Sea, the Baltic Sea and the Black Sea. Seasonal changes in physiological parameters (gonad index, condition index, biochemical composition and respiration rate) of M. arenaria from the Baltic Sea (the Gulf of Gdańsk, Poland), and the North Sea (Versee Meer, the Netherlands) were studied. The sex ratio of both populations did not differ from 1:1 and the seasonal gonad index was higher in the Baltic population. The average condition index changed seasonally at both studied sites, and was also higher in the Baltic population (except the autumn) compared to the North Sea. In both studied populations, the content of proteins, lipids and carbohydrates in the soft tissue followed the seasonal variations, and it was higher in the Baltic population. The respiration rate was lower in the Baltic population, and seasonal changes in the respiration rate seem to be correlated with changes in the water temperature. Based on the results obtained in the present study, we suggest that Mya arenaria is characterized by a large phenotypic plasticity and differences in the observed physiological traits are due to acclimatization to ambient environmental conditions.

Inflation aversion in transition countries: Empirical evidence from the Baltic States

In command economies, inflation is either absent or at least unrelated to supply and demand. However, when the economies in Eastern Europe started transforming into market economies, they suddenly experienced high and volatile inflation rates. Transformation countries are therefore interesting laboratories for studying individual inflation aversion. In this paper we study the level and determinants of individual inflation aversion in the three Baltic countries. Using data from 11 waves of the Eurobarometer survey, we find age, education and the macroeconomic situation to have significant effects on the likelihood to mention inflation among the most important problems facing the country. Moreover, we find the populations of all three Baltic countries to be significantly more inflation averse than the population of the United Kingdom, a western democracy with a long tradition as a market economy. We attribute this finding to the specific experiences of the Baltic populations with inflation.

Fatty acid and elemental composition of littoral “green tide” algae from the Gulf of Finland, the Baltic Sea

Coastal eutrophication leads to a shift in primary producer communities from perennial species to ephemeral fast-growingspeciesofmacroalgae,whichisknownas"green tides" phenomenon. In brackish water habitats of the Baltic Sea,theopportunisticgreenalgae,Cladophoraglomerataand Ulva intestinalis, replaced the brown alga Fucus vesiculosus, while in freshwater estuarine parts they replaced epilithic microalgae. We studied Baltic populations of the macroalgae, C. glomerata and U. intestinalis, and epilithic and epiphytic microalgae, with respect to their nutritive quality, such as content of essential polyunsaturated fatty acids (PUFAs) and elemental composition. Fatty acid profiles of the two macroalgae were significantly different, including levels of essential PUFAs. We found a relatively high content of eicosapentaenoic acid (EPA; 20:5n�3) in C. glomerata bio- mass (4.14 mg g �1 C), whereas U. intestinalis had a lower value (0.45 mg g �1 C). Comparison with literature data showed that C. glomerata appeared to be a more valuable food for potential invertebrate consumers in respect to EPA content and stoichiometric C/P ratio than perennial F. vesiculosus and U. intestinalis. Thus, replacement of F.vesiculosusand epilithicmicroalgaebyC. glomeratawould not decrease the potential nutritive value of coastal algal communities for invertebrates. In turn, if U. intestinalis dom- inate in algal community, the nutritive value of primary pro- ducers in coastal zone would decrease. However, in following works, other important indicators of nutritive value, such as sterols and amino acids, should be included in the estimations of green tide algae species.

Genetic differentiation of brackish water populations of cod Gadus morhua in the southern Baltic, inferred from genotyping using SNP-arrays

The Baltic is a semi-enclosed sea characterised by decreasing salinity in the eastern and northern direction with only the deeper parts of the southern Baltic suitable as spawning grounds for marine species like cod. Baltic cod exhibits various adaptations to brackish water conditions, yet the inflow of salty North Sea water near the bottom remains an influence on the spawning success of the Baltic cod. The eastern Baltic population has been very weakly studied in comparison with the western population.The aim of this study is to demonstrate for the first time genetic differentiation by the use of a large number of SNPs between eastern and western Baltic populations existing in differentiated salinity conditions. Two cod samples were collected from the Bay of Gdańsk, Poland and one from the Kiel Bight, Germany. Samples were genotyped using a cod derived SNP-array (Illumina) with 10 913 SNPs. A selection of diagnostic SNPs was performed. A set of 7944 validated SNPs were analysed to assess the differentiation of three samples of cod. Results indicated a clear distinctness of the Kiel Bight from the populations of the eastern Baltic. FST comparison between both eastern samples was non-significant. Clustering analysis, principal coordinates analysis and assignment test clearly indicated that the eastern samples should be considered as one subpopulation, well differentiated from the western subpopulation. With the SNP approach, no differentiation between groups containing ‘healthy’ and ‘non-healthy’ cod individuals was observed.

New SNP markers reveal largely concordant clinal variation across the hybrid zone between Mytilus spp. in the Baltic Sea

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 21:25-36 (2014) - DOI: https://doi.org/10.3354/ab00566 New SNP markers reveal largely concordant clinal variation across the hybrid zone between Mytilus spp. in the Baltic Sea Małgorzata Zbawicka1,*, Tomasz Sańko1, Jakob Strand2, Roman Wenne1 1Institute of Oceanology PAS, Powstańców Warszawy 55, 81-712 Sopot, Poland 2Arhus University, Department of Bioscience, 4000 Roskilde, Denmark *Corresponding author: mzbawicka@iopan.gda.pl ABSTRACT: Environmental conditions such as a pronounced salinity gradient and postglacial history make the Baltic Sea a suitable area for studying how selection and gene flow affect genetic differentiation in marine species. A cDNA library was used to identify new single nucleotide polymorphisms (SNPs) in Baltic populations of Mytilus spp. mussels. Sixty polymorphic SNPs were used to genotype 642 individual mussels from the inner Baltic, Danish Straits, northwest Denmark and a population of the northeast Pacific. We characterized 49 novel SNP markers that differentiate the populations of the North and Baltic Sea areas. Concordant narrow clines were observed at the entrance of the Baltic Sea for most of these markers. Considerable variance of hybrid index scores was observed in populations with intermediate allele frequencies within the hybrid zone, e.g. in Gedser and Hjelm. The presented results are in accordance with the existence of strong reproductive isolation, probably caused by a combination of exogenous (e.g. adaptation to brackish waters) and endogenous pre- and post-zygotic factors (e.g. selection against hybrids). The overwhelming majority of new SNPs markers showed a larger representation of M. trossulus than M. edulis genes in the nuclear DNA of Baltic Mytilus species. Finally, we identified a few markers with an elevated level of introgression of M. edulis alleles in the Baltic Sea M. trossulus populations in comparison to the reference M. trossulus population of the Pacific. KEY WORDS: Population structure · Hybrid index score · Single locus clines · Diagnostic markers Full text in pdf format Supplementary material PreviousNextCite this article as: Zbawicka M, Sańko T, Strand J, Wenne R (2014) New SNP markers reveal largely concordant clinal variation across the hybrid zone between Mytilus spp. in the Baltic Sea. Aquat Biol 21:25-36. https://doi.org/10.3354/ab00566 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 21, No. 1. Online publication date: June 03, 2014 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2014 Inter-Research.

Erratum

Animal GeneticsVolume 45, Issue 1 p. 155-155 ErratumFree Access Erratum This article corrects the following: Genetic differentiation of southeast Baltic populations of sea trout inferred from single nucleotide polymorphisms A. Poćwierz-Kotus, R. Bernaś, P. Dębowski, M. P. Kent, S. Lien, M. Kesler, S. Titov, E. Leliūna, H. Jespersen, A. Drywa, R. Wenne, Volume 45Issue 1Animal Genetics pages: 96-104 First Published online: November 15, 2013 First published: 10 January 2014 https://doi.org/10.1111/age.12130Citations: 2AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL The Publisher would like to extend our sincerest apologies for the erroneous copyright line in Poćwierz-Kotus et al (2014). The copyright line was corrected on 16 December 2013 and as follows, after first online publication: © 2013 Stichting International Foundation for Animal Genetics References Poćwierz-Kotus A., Bernaś R., Debowski P., Kent M.P., Lien S., Kesler M., Titov S., Leliuna E., Jespersen H., Drywa A. & Wenne R (2014) Genetic differentiation of southeast Baltic populations of sea trout inferred from single nucleotide polymorphisms. Animal Genetics 45, 96– 104. Citing Literature Volume45, Issue1February 2014Pages 155-155 ReferencesRelatedInformation

MRNA expression of genes regulating lipid metabolism in ringed seals (Pusa hispida) from differently polluted areas

There is a growing concern about the ability of persistent organic pollutants (POPs) to influence lipid metabolism. Although POPs are found at high concentrations in some populations of marine mammals, for example in the ringed seal (Pusa hispida) from the Baltic Sea, little is known about the effects of POPs on their lipid metabolism. An optimal regulation of lipid metabolism is crucial for ringed seals during the fasting/molting season. This is a physiologically stressful period, during which they rely on the energy stored in their fat reserves. The mRNA expression levels for seven genes involved in lipid metabolism were analyzed in liver and/or blubber tissue from molting ringed seals from the polluted Baltic Sea and a less polluted reference location, Svalbard (Norway). mRNA expression of genes encoding peroxisome proliferator-activated receptors (PPAR) α and γ and their target genes acyl-coenzyme A oxidase 1 (ACOX1) and cluster of differentiation 36 (CD36) were analyzed in liver. mRNA expression level of genes encoding PPARβ, PPARγ and their target genes encoding fatty acid binding protein 4 (FABP4) and adiponectin (ADIPOQ) were measured in inner and middle blubber layers. In addition, we evaluated the influence of molting status on hepatic mRNA expression of genes encoding PPARs and their target genes in ringed seals from Svalbard. Our results show higher mRNA expression of genes encoding hepatic PPARγ and adipose PPARβ, FABP4, and ADIPOQ in the Baltic seals compared to the Svalbard seals. A positive relationship between mRNA expressions of genes encoding hepatic PPARγ, adipose FABP4, adipose ADIPOQ and ΣPOP concentrations was observed. These findings suggest that lipid metabolism may be affected by contaminant exposure in the Baltic population. mRNA expression of genes encoding PPARβ, PPARγ, FABP4 and ADIPOQ were similar between the mid and inner adipose layer. Hepatic mRNA expression of genes encoding PPARα and PPARγ was higher in the pre-molting individuals compared to the molting ones highlighting differential regulation of these metabolic sensors through the molting period.

Life history of theGlanville fritillary butterfly in fragmented versus continuous landscapes

Habitat loss and fragmentation threaten the long-term viability of innumerable species of plants and animals. At the same time, habitat fragmentation may impose strong natural selection and lead to evolution of life histories with possible consequences for demographic dynamics. The Baltic populations of the Glanville fritillary butterfly (Melitaea cinxia) inhabit regions with highly fragmented habitat (networks of small dry meadows) as well as regions with extensive continuous habitat (calcareous alvar grasslands). Here, we report the results of common garden studies on butterflies originating from two highly fragmented landscapes (FL) in Finland and Sweden and from two continuous landscapes (CL) in Sweden and Estonia, conducted in a large outdoor cage (32 by 26 m) and in the laboratory. We investigated a comprehensive set of 51 life-history traits, including measures of larval growth and development, flight performance, and adult reproductive behavior. Seventeen of the 51 traits showed a significant difference between fragmented versus CL. Most notably, the growth rate of postdiapause larvae and several measures of flight capacity, including flight metabolic rate, were higher in butterflies from fragmented than CL. Females from CL had shorter intervals between consecutive egg clutches and somewhat higher life-time egg production, but shorter longevity, than females from FL. These results are likely to reflect the constant opportunities for oviposition in females living in continuous habitats, while the more dispersive females from FL allocate more resources to dispersal capacity at the cost of egg maturation rate. This study supports theoretical predictions about small population sizes and high rate of population turnover in fragmented habitats selecting for increased rate of dispersal, but the results also indicate that many other life-history traits apart from dispersal are affected by the degree of habitat fragmentation.

Genetic differentiation of southeast Baltic populations of sea trout inferred from single nucleotide polymorphisms

Sea trout (Salmo trutta m. trutta) is a migratory form of brown trout common in the Baltic Sea. Nine populations from the southeast Baltic (Poland; Lithuania; Denmark, Bornholm; Estonia and Russia) were genotyped using iPLEX Gold technology (Sequenom) with 62 informative SNPs. A diagnostic panel of 23 SNPs was applied to estimate genetic differentiation and assess the population structure of Baltic sea trout. The highest level of pairwise FST differences was observed between the Russian (East Gulf of Finland) and Polish (Baltic main basin) populations. The lowest differences were between the two Polish and the Polish and Lithuanian populations. A genetic similarity was noted between the Estonian Riguldi River and Danish Bornholm populations, and this finding was supported by a Bayesian and factorial correspondence analysis. Diversity within populations was highest for populations from Estonia and lowest for the Lithuanian population. Genetic structure analysis indicated that individuals from the nine populations were clustered into four groups.

Biometrics of Razorbills Alca torda staying during the nonbreeding season in the Polish Baltic zone

Biometrical analysis of Razorbills Alca torda captured or drowned in fishing nets in the Polish economic zone of the Baltic Sea is based on measurements of 98 individuals collected in the non-breeding period (October–April) in 2006–2013. These birds are assumed to represent the breeding population of the Baltic Sea as recoveries show that very few other birds visit that area. Bill depth and wing length of juveniles were much smaller than in older birds which suggests that the final size of these measurements is not achieved during the first winter but continue to increase as the birds grow older. In older birds only total head length and bill length were significantly larger in males than in females. Mean bill depth of Razorbills from the Polish Baltic zone fits well to clinal variation from south-west to north of the European part of the breeding range. However, mean wing length was much larger than expected according to the regression, which might result from differences in measuring technique. On the other hand it cannot be excluded that the Baltic population may actually have longer wings.

The genetic structure of the Lithuanian wolf population

Abstract Lithuanian wolves form part of the larger Baltic population, the distribution of which is continuous across the region. In this paper, we evaluate the genetic diversity of the Lithuanian wolf population using mitochondrial DNA analysis and 29 autosomal microsatellite loci. Analysis of the mtDNA control region (647 bp) revealed 5 haplotypes distributed among 29 individuals and high haplotype diversity (0.658). Two haplotypes were distributed across the country, whilst the others were restricted to eastern Lithuania. Analysis of microsatellites revealed high heterozygosity (HE=0.709) and no evidence for a recent bottleneck. Using detection of first generation migrants, four individuals appeared to assign better with populations genetically differentiated from those resident in Lithuania. These immigrants were males carrying rare mitochondrial haplotypes and were encountered in the eastern part of the country, this indicates that Lithuania is subject to immigration from differentiated populations. Additionally, we did not detect any signs of recent hybridisation with dogs.

Patterns of post-glacial genetic differentiation in marginal populations of a marine microalga.

This study investigates the genetic structure of an eukaryotic microorganism, the toxic dinoflagellate Alexandrium ostenfeldii, from the Baltic Sea, a geologically young and ecologically marginal brackish water estuary which is predicted to support evolution of distinct, genetically impoverished lineages of marine macroorganisms. Analyses of the internal transcribed spacer (ITS) sequences and Amplified Fragment Length Polymorphism (AFLP) of 84 A. ostenfeldii isolates from five different Baltic locations and multiple external sites revealed that Baltic A. ostenfeldii is phylogenetically differentiated from other lineages of the species and micro-geographically fragmented within the Baltic Sea. Significant genetic differentiation (F ST) between northern and southern locations was correlated to geographical distance. However, instead of discrete genetic units or continuous genetic differentiation, the analysis of population structure suggests a complex and partially hierarchic pattern of genetic differentiation. The observed pattern suggests that initial colonization was followed by local differentiation and varying degrees of dispersal, most likely depending on local habitat conditions and prevailing current systems separating the Baltic Sea populations. Local subpopulations generally exhibited low levels of overall gene diversity. Association analysis suggests predominately asexual reproduction most likely accompanied by frequency shifts of clonal lineages during planktonic growth. Our results indicate that the general pattern of genetic differentiation and reduced genetic diversity of Baltic populations found in large organisms also applies to microscopic eukaryotic organisms.

Menstrual Cycle and Respiratory Symptoms in a General Nordic–Baltic Population

There is little knowledge of variations in respiratory symptoms during the menstrual cycle in a general population, and potential modifying factors are not investigated. To investigate menstrual cycle variation in respiratory symptoms in a large general population, using chronobiology methodology, and stratifying by body mass index (BMI), smoking, and asthma status. A total of 3,926 women with regular cycles less than or equal to 28 days and not taking exogenous sex hormones answered a postal questionnaire regarding the first day of their last menstruation and respiratory symptoms in the last 3 days. Moving 4-day means were computed to smooth uneven records of daily sampling; best-fitting 28-day composite cosine curves were applied to each time series to describe rhythmicity. Significant rhythmic variations over the menstrual cycle were found in each symptom for all subjects and subgroups. Wheezing was higher on cycle Days 10-22, with a midcycle dip near the time of putative ovulation (approximately Days 14-16) in most subgroups. Shortness of breath was higher on days 7-21, with a dip just before midcycle in many subgroups. Cough was higher just after putative ovulation for subjects with asthma, BMI greater than or equal to 23 kg/m(2), and smokers, or just before ovulation and menses onset for low symptomatic subgroups. Respiratory symptoms varied significantly during the menstrual cycle and were most frequent from the midluteal to midfollicular stages, often with a dip near the time of ovulation. The patterns varied by BMI, smoking, and asthma status. These relations link respiratory symptoms with hormonal changes through the menstrual cycle and imply a potential for individualized chronotherapy for respiratory diseases.

Palaeogenetics of western French sturgeons spotlights the relationships between Acipenser sturio and Acipenser oxyrinchus

AbstractAimThe Atlantic sturgeon, Acipenser oxyrinchus, was long considered an American species, but recent discoveries based on analyses of archaeological remains proved its presence in the Baltic Sea and in France. This came as a surprise, as the European sturgeon, Acipenser sturio, was thought to be the only sturgeon species present on the European Atlantic coast. It was hypothesized that migrants from North America founded the Baltic population of Atlantic sturgeons around 1200 years ago.LocationThe sampling is composed of five sturgeon archaeological remains (5000–1800 yr bp) and 21 naturalized or ethanol‐preserved museum specimens from the 19th and 20th centuries, originating from the French Atlantic coast.MethodsAnalyses of ancient DNA were performed following the strict criteria of the field to avoid contamination and to ensure sequence authentication. A 210‐bp fragment of the control region (CR) was sequenced and three microsatellite loci were sized and sequenced.ResultsOut of a total of 26 samples, three archaeological remains and six museum specimens produced A. oxyrinchus mitochondrial or nuclear sequences; two of these museum samples showed signs of hybridization between A. sturio and A. oxyrinchus. All the other samples yielded only A. sturio DNA sequences, and a new CR haplotype was described in this species.Main conclusionsMolecular evidence of sympatry and natural hybridization between A. sturio and A. oxyrinchus on the French Atlantic coast – specifically the hybrid evidence of two museum specimens collected from the Seine River in 1823 and 1858 – challenge our understanding of the species' past relationships. In light of these findings, new hypotheses are presented to explain the history and geographical range of A. oxyrinchus in Europe.

Genotyping of two populations of Southern Baltic Sea trout Salmo trutta m. trutta using an Atlantic salmon derived SNP-array

The sea trout (Salmo trutta m. trutta) is an anadromous, teleost fish species characterized by homing behaviour. The sea trout has considerable ecological and economic significance. It reproduces naturally in rivers flowing into, and is common in, the Baltic Sea. In Poland spawning aggregations occur in the Vistula River and the rivers of Pomerania. Two populations from the Vistula River (TW) and a Pomeranian river, the Słupia (TP) were mixed in the past by stocking. The main purpose of this study was an assessment of the applicability of the Atlantic salmon custom design Illumina iSelect SNP (Single Nucleotide Polymorphisms) array containing 15,225 markers for identification of genetic diversity between sea trout populations. A diagnostic panel of 39 SNPs with a mean FST=0.1298 was selected from a pool of 15,225. At each locus, minor allele frequency was higher than 0.01 and mean expected heterozygosity for TW and TP populations were 0.343 and 0.271 respectively. Individuals tested were clustered in one of two groups which corresponded to their origins where the TW population was genetically more homogenous (membership coefficients ranked from 88.8% to 98.6%) while the TP population was more diverse (membership coefficients ranked from 53.8% to 98.5%). The results demonstrated the applicability of the Salmon 15K SNP-chip for determining the differences between Southern Baltic populations of the sea trout, a closely related salmonid species.

SNP‐array reveals genome‐wide patterns of geographical and potential adaptive divergence across the natural range of Atlantic salmon (Salmo salar)

Atlantic salmon (Salmo salar) is one of the most extensively studied fish species in the world due to its significance in aquaculture, fisheries and ongoing conservation efforts to protect declining populations. Yet, limited genomic resources have hampered our understanding of genetic architecture in the species and the genetic basis of adaptation to the wide range of natural and artificial environments it occupies. In this study, we describe the development of a medium-density Atlantic salmon single nucleotide polymorphism (SNP) array based on expressed sequence tags (ESTs) and genomic sequencing. The array was used in the most extensive assessment of population genetic structure performed to date in this species. A total of 6176 informative SNPs were successfully genotyped in 38 anadromous and freshwater wild populations distributed across the species natural range. Principal component analysis clearly differentiated European and North American populations, and within Europe, three major regional genetic groups were identified for the first time in a single analysis. We assessed the potential for the array to disentangle neutral and putative adaptive divergence of SNP allele frequencies across populations and among regional groups. In Europe, secondary contact zones were identified between major clusters where endogenous and exogenous barriers could be associated, rendering the interpretation of environmental influence on potentially adaptive divergence equivocal. A small number of markers highly divergent in allele frequencies (outliers) were observed between (multiple) freshwater and anadromous populations, between northern and southern latitudes, and when comparing Baltic populations to all others. We also discuss the potential future applications of the SNP array for conservation, management and aquaculture.