Baltic Populations Research Articles

Pantothenic acid - a scoping review for Nordic Nutrition Recommendations 2023.

Pantothenic acid, also referred to as vitamin B5, is a water-soluble vitamin that has essential functions in the body as a component of coenzyme A (CoA) and acyl carrier protein (ACP). It is widely distributed in animal and plant-source foods. Nutritional deficiency of pantothenic acid is rare and toxicity negligible. Information on pantothenic acid intakes in the Nordic countries is limited and biomarker data from Nordic and Baltic populations is missing. Due to a lack of data, no dietary reference values (DRVs) were given for pantothenic acid in the Nordic Nutrition Recommendations (NNR) since 2012. The aim of this scoping review was to examine recent evidence relevant for updating the DRVs for NNR2023. Scientific literature since 2012 on associations of pantothenic acid with health-related issues in Nordic and Baltic countries was searched. No health concerns related to pantothenic acid were identified.

Thiamin dynamics during the adult life cycle of Atlantic salmon (Salmo salar).

Thiamin is an essential water-soluble B vitamin known for its wide range of metabolic functions and antioxidant properties. Over the past decades, reproductive failures induced by thiamin deficiency have been observed in several salmonid species worldwide, but it is unclear why this micronutrient deficiency arises. Few studies have compared thiamin concentrations in systems of salmonid populations with or without documented thiamin deficiency. Moreover, it is not well known whether and how thiamin concentration changes during the marine feeding phase and the spawning migration. Therefore, samples of Atlantic salmon (Salmo salar) were collected when actively feeding in the open Baltic Sea, after the sea migration to natal rivers, after river migration, and during the spawning period. To compare populations of Baltic salmon with systems without documented thiamin deficiency, a population of landlocked salmon located in Lake Vänern (Sweden) was sampled as well as salmon from Norwegian rivers draining into the North Atlantic Ocean. Results showed the highest mean thiamin concentrations in Lake Vänern salmon, followed by North Atlantic, and the lowest in Baltic populations. Therefore, salmon in the Baltic Sea seem to be consistently more constrained by thiamin than those in other systems. Condition factor and body length had little to no effect on thiamin concentrations in all systems, suggesting that there is no relation between the body condition of salmon and thiamin deficiency. In our large spatiotemporal comparison of salmon populations, thiamin concentrations declined toward spawning in all studied systems, suggesting that the reduction in thiamin concentration arises as a natural consequence of starvation rather than to be related to thiamin deficiency in the system. These results suggest that factors affecting accumulation during the marine feeding phase are key for understanding the thiamin deficiency in salmonids.

Baltic Population of the Barnacle Goose (Branta leucopsis (Bechstein 1803)) in the Boreal Zone of Northwestern Russia

Baltic Population of the Barnacle Goose (Branta leucopsis (Bechstein 1803)) in the Boreal Zone of Northwestern Russia

Vitamin A - a scoping review for Nordic nutrition Recommendations 2023.

Vitamin A refers to a group of fat-soluble compounds with retinol activity, including all-trans retinol and pro-vitamin A carotenoids. Bioactive compounds include retinal and all-trans retinoic acid with important functions in vision, immune function, growth, and development. The literature search that was performed for the current scoping review yielded a total of seven publications relevant to setting the recommended daily intake for vitamin A. In total, six publications assessed the relationship of serum retinol and/or dietary vitamin A intake with fracture risk (n = 2), cancer (n = 3), and deficiency after bariatric surgery (n = 1). One additional report by the European Food Safety Administration (EFSA) with updated average requirements was included. The outcomes-based systematic reviews and meta-analyses showed positive associations for vitamin A intake and serum retinol with risk of hip fracture. Weak or inconclusive associations were observed for cancer or obesity. One publication by EFSA with updated estimated average requirements and population reference intakes for dietary vitamin A intakes was published in 2015. The EFSA recommendations and estimated average requirements are based on a European reference population, with body weights derived from an assumed body mass index of 22, which might be too low and not representative of the Nordic and Baltic populations, and consequently resulting in lower estimated average requirements and recommendations. In conclusion, there were limited new outcomes-based data for vitamin A and health outcomes.

Genome-environment association analyses reveal geographically restricted adaptive divergence across the range of the widespread Eurasian carnivore Lynx lynx (Linnaeus, 1758).

Local adaptations to the environment are an important aspect of the diversity of a species and their discovery, description and quantification has important implications for the fields of taxonomy, evolutionary and conservation biology. In this study, we scan genomes from several populations across the distributional range of the Eurasian lynx, with the objective of finding genomic windows under positive selection which may underlie local adaptations to different environments. A total of 394 genomic windows are found to be associated to local environmental conditions, and they are enriched for genes involved in metabolism, behaviour, synaptic organization and neural development. Adaptive genetic structure, reconstructed from SNPs in candidate windows, is considerably different than the neutral genetic structure of the species. A widespread adaptively homogeneous group is recovered occupying areas of harsher snow and temperature climatic conditions in the north-western, central and eastern parts of the distribution. Adaptively divergent populations are recovered in the westernmost part of the range, especially within the Baltic population, but also predicted for different patches in the western and southern part of the range, associated with different snow and temperature regimes. Adaptive differentiation driven by climate does not correlate much with the subspecies taxonomic delimitations, suggesting that subspecific divergences are mostly driven by neutral processes of genetic drift and gene flow. Our results will aid the selection of source populations for assisted gene flow or genetic rescue programs by identifying what climatic patterns to look for as predictors of pre-adaptation of individuals. Particularly, the Carpathian population is confirmed as the best source of individuals for the genetic rescue of the endangered, isolated and genetically eroded Balkan population. Additionally, reintroductions in central and western Europe, currently based mostly on Carpathian lynxes, could consider the Baltic population as an additional source to increase adaptive variation and likely improve adaptation to their milder climate.

Morphometrics, Growth and Condition of the Invasive Bivalve Rangia cuneata during Colonisation of the Oder Estuary (North-Western Poland)

The aim of this study was to determine the biological, morphometric, and shape characteristics of the bivalve Rangia cuneata in the initial phase of colonisation. A total of 504 specimens were caught for the study. Their average length was 31.06 mm (range 12.7–43.2 mm) and weight 6.0 g (0.5–15.3 g). The population was dominated by individuals of 25–30 mm and 30–35 mm in length and the age of 3+ and 4+. The standard major axis regression for measurable traits describing shell cross-section indicate the allometric nature of growth for most parameters. Elongation and convexity indices by age group indicate a change in the shell shape as it becomes more elongated and convex in individuals that have already reached sexual maturity. The collected specimens were of larger sizes compared to other Baltic populations of the species, and similar in size to populations found in the neighboring Pomeranian Bay. The increase in length of R. cuneata in the Oder estuary is smaller compared to the species native sites, probably due to the lower water temperature in the study area. Considering the invasive potential of R. cuneata, it seems necessary to monitor closely its population and distribution in the estuary of Western Baltic.

Interdisciplinary Analyses of Bronze Age Communities from Western Hungary Reveal Complex Population Histories.

In this study, we report 21 ancient shotgun genomes from present-day Western Hungary, from previously understudied Late Copper Age Baden, and Bronze Age Somogyvár-Vinkovci, Kisapostag, and Encrusted Pottery archeological cultures (3,530-1,620 cal Bce). Our results indicate the presence of high steppe ancestry in the Somogyvár-Vinkovci culture. They were then replaced by the Kisapostag group, who exhibit an outstandingly high (up to ∼47%) Mesolithic hunter-gatherer ancestry, despite this component being thought to be highly diluted by the time of the Early Bronze Age. The Kisapostag population contributed the genetic basis for the succeeding community of the Encrusted Pottery culture. We also found an elevated hunter-gatherer component in a local Baden culture-associated individual, but no connections were proven to the Bronze Age individuals. The hunter-gatherer ancestry in Kisapostag is likely derived from two main sources, one from a Funnelbeaker or Globular Amphora culture-related population and one from a previously unrecognized source in Eastern Europe. We show that this ancestry not only appeared in various groups in Bronze Age Central Europe but also made contributions to Baltic populations. The social structure of Kisapostag and Encrusted Pottery cultures is patrilocal, similarly to most contemporaneous groups. Furthermore, we developed new methods and method standards for computational analyses of ancient DNA, implemented to our newly developed and freely available bioinformatic package. By analyzing clinical traits, we found carriers of aneuploidy and inheritable genetic diseases. Finally, based on genetic and anthropological data, we present here the first female facial reconstruction from the Bronze Age Carpathian Basin.

Ecological adaptation in cod and herring and possible consequences of future climate change in the Baltic Sea

The Atlantic herring and Atlantic cod are two marine fish species that have successfully adapted to the brackish Baltic Sea, and the former is able to spawn in near-freshwater conditions in the inner Gulf of Bothnia. Here, we review the state of current knowledge concerning ecological adaptation in the two species and make an attempt to predict how they will be able to cope with future climate change. Previous whole genome sequencing studies in Atlantic herring have revealed hundreds of genetic loci underlying ecological adaptation, including several loci that show very strong associations to variation in salinity and temperature. These results suggest the existence of standing genetic variation available for adaptation to a changing environment. However, although Atlantic herring probably has the genetic potential to adapt, its future status also depends on how climate change will affect plankton production and competing species, such as sprat and three-spined stickleback. In cod, the situation is challenging, as there is only one true Baltic population, spawning east of Bornholm and then dispersing towards the east and north. This Baltic cod population is threatened by overfishing, low oxygen levels in benthic waters and generally bad physiological condition of individual fish, in addition to being completely isolated from gene flow from nearby cod populations at the entrance of the Baltic Sea.

Infection of the European flounder (Platichthys flesus) with Glugea stephani, a possible new indicator of the weakening of the Baltic population

The strict limitations on the fishing quotas for Atlantic cod (Gadus morhua) have meant the European flounder (Platichthys flesus) has become the third most commercially fished species in the Baltic Sea. Recent reports from the International Council for the Exploration of the Sea and local fishermen, however, indicate a noticeable decline in the fitness of the species and catch volume in the Baltic Sea over the last decade. As the alimentary tract is one of the major entry routes for toxicants and parasites, and since any disturbances in its functioning are directly responsible for harmful changes in the health and welfare of the fish, a diachronic examination of the digestive tract of the European flounder sampled from the Slupsk Bank was carried out in order to determine possible factors behind the observed detrimental changes in its success in the Baltic Sea. The results obtained revealed a serious Glugea stephani infection and the presence of microsporidiosis in the fish studied (a prevalence of 41.9 % and a mean infection intensity of 9.15 xenomas per fish) considerably higher than those previously reported in less polluted regions studied across Atlantic and Pacific. This may suggest the influence of factors conducive to improving the success rate of the invading parasite, such as an increased level of environmental pollution and oxygen deficiency on the sea bottom, both of which contribute to a greater density of fish in a limited area. Our study indicates the need for comprehensive parasitological investigation of the European flounder in the Baltic Sea, in order to study microsporidiosis and the level of parasitic infection detected in histopathological and molecular analyses, including metacercariae of Zoogonoidae, nematodes of Cucullanidae, Anisakidaea and Parafilaroides normani. This study detected Parafilaroides normani, hitherto unknown in Europe, with a probability of 91.41 %.

Кони Бирки

The data presented in this article on horse burials in the Scandinavian burial ground of Birka (Sweden) suggest the existence of trade relations between the population of southeastern Scandinavia of the Viking Age and the western Baltic inhabitants of the Amber Coast. These contacts could be based on the supply of raw amber to the north of Europe. In parallel, Prussian horses were supplied to Scandinavia, equipped with authentic headbands for funeral ceremonies. This part of the Balto-Scandinavian contacts is extremely interesting, first of all, because the cult of the horse and its role in the funeral ceremony, associated with the solar cult of the Ashvin twins, is a specific feature of the spiritual culture of the Baltic population of the entire Eastern Baltic region. The representation of horse burials in the Scandinavian funerary antiquities of the Viking Age suggests the influence of the features of the Baltic spiritual culture on the cult of the northerners of Europe. In truth, the burial of a horse with riding equipment, which accompanied the grave of the leader, is known in Scandinavian legends about pre-Christian times.

Assessment of Eurasian lynx reintroduction success and mortality risk in north-west Poland

Despite recent local reintroductions of the Eurasian lynx Lynx lynx in central and north-eastern Poland, the increase in its population was not followed by its westward expansion. To address this problem and restore the lynx population in north-western Poland, 61 captive-born individuals of Baltic population origin were released in the province of Western Pomerania in 2019–2021. Prior to their release, all the animals underwent an adaptation training phase. They were then set free according to a hard-release protocol and subsequently monitored by means of GPS telemetry. In order to assess the short-term reintroduction success, the survival and causes of death of the released individuals were studied as a function of sex, age, training time, and release time and place. The overall survival rate was 71.15%, the median survival time 202 days. Most mortality, due to environmental factors, i.e. scabies (> 200 days) or traffic collisions (< 200 days), was recorded during the first 300 days following release. Age, year of release and training time were significantly related to survival, indicating that the older the lynx was when released, the better its survival changes. In contrast, the longer the training time, the poorer were the chances of survival. There was no evidence of any effect of sex, month of release or place of release. Based on these results, recommendations were made for the planning of further releases and measures to manage the restored population.

Natural Regulation of the Baltic Population of the Great Cormorant Phalacrocorax carbo sinensis: The Interplay between Winter Severity and Density Dependence

After a period of continuous increase and range expansion, the Baltic Great Cormorant population has stabilised in large parts of its range in recent years. Ringing recoveries reveal that considerable proportions of the population winter in areas that can be affected by prolonged frost periods. There is evidence that winter severity is an important density-dependent regulation factor: if the population is large, ice cover of coastal and inland water surfaces during harsh winters affects the population by reducing the availability of food resources. As long as the population remained small, however, it was not affected even by very cold winters, since the remaining accessible food resources were presumably still sufficient. The analysis presented here uses the average winter temperature in Germany as a proxy for winter severity in the frost-affected parts of the wintering areas of Baltic Cormorants. The Baltic Cormorant population in 1980–2016 is estimated from annual counts in Denmark, Schleswig-Holstein, Mecklenburg-Western Pomerania, Estonia, Finland and Gotland, which account for about 50% of the total population. The interplay between winter severity and density dependence is analysed using a linear and a non-linear regression model approach. The non-linear model gives a better description of the relationship between the size of the Baltic breeding population during the year (n), the winter temperature Tn, and the population size during the previous year (n–1). According to the model, a population of less than 41,400 breeding pairs would not suffer declines during even the coldest winters recorded since 1882. In 1989, the Baltic Cormorant population exceeded for the first time the threshold value for density-dependent regulation caused by severe winters. The winter 1995/96 was then the first one cold enough to cause a population decline. According to the model, during the years 2002/2003, 2005/06, 2008/09, 2009/10 and 2010/11 the winters have been cold enough to reduce population numbers. Furthermore, the model shows that the regulative winter effect is restricted to the low temperature range.

LT1, an ONT long-read-based assembly scaffolded with Hi-C data and polished with short reads.

We present LT1, the first high-quality human reference genome from the Baltic States. LT1 is a female de novo human reference genome assembly, constructed using 57× nanopore long reads and polished using 47× short paired-end reads. We utilized 72GB of Hi-C chromosomal mapping data for scaffolding, to maximize assembly contiguity and accuracy. The contig assembly of LT1 was 2.73Gbp in length, comprising 4490 contigs with an NG50 value of 12.0Mbp. After scaffolding with Hi-C data and manual curation, the final assembly has an NG50 value of 137Mbp and 4699 scaffolds. Assessment of gene prediction quality using Benchmarking Universal Single-Copy Orthologs (BUSCO) identified 89.3% of the single-copy orthologous genes included in the benchmark. Detailed characterization of LT1 suggests it has 73,744 predicted transcripts, 4.2million autosomal SNPs, 974,616 short indels, and 12,079 large structural variants. These data may be used as a benchmark for further in-depth genomic analyses of Baltic populations.

Habitat selection and foraging site fidelity in Caspian Terns (Hydroprogne caspia) breeding in the Baltic Sea

Habitat preferences and foraging strategies affect population-level space use and are therefore crucial to understanding population change and implementing spatial conservation and management actions. We investigated the breeding season habitat preference and foraging site fidelity of the under-studied and threatened, Baltic Sea population of Caspian Terns (Hydroprogne caspia). Using GPS devices, we tracked 20 adult individuals at two breeding colonies, in Sweden and Finland, from late incubation through chick-rearing. Analyzing foraging movements during this period, we describe trip characteristics for each colony, daily metrics of effort, habitat use, and foraging site fidelity. We found that daily time spent away from the colony increased throughout the season, with colony-level differences in terms of distance travelled per day. In general, terns selected shallow waters between 0–5 meters in depth with certain individuals using inland lakes for foraging. We show, for the first time, that individual Caspian Terns are faithful to foraging sites throughout the breeding season, and that individuals are highly repeatable in their strategies regarding foraging site fidelity. These results fill important knowledge gaps for this at-risk population, and extend our general knowledge of the breeding season foraging ecology of this widespread species.

Complex and divergent histories gave rise to genome-wide divergence patterns amongst European whitefish (Coregonus lavaretus).

Pleistocene glaciations dramatically affected species distribution in regions that were impacted by ice cover and subsequent postglacial range expansion impacted contemporary biodiversity in complex ways. The European whitefish, Coregonus lavaretus, is a widely distributed salmonid fish species on mainland Europe, but in Britain it has only seven native populations, all of which are found on the western extremes of the island. The origins and colonization routes of the species into Britain are unknown but likely contributed to contemporary genetic patterns and regional uniqueness. Here, we used up to 25,751 genome‐wide polymorphic loci to reconstruct the history and to discern the demographic and evolutionary forces underpinning divergence between British populations. Overall, we found lower genetic diversity in Scottish populations but high differentiation (F ST = 0.433–0.712) from the English/Welsh and other European populations. Differentiation was elevated genome‐wide rather than in particular genomic regions. Demographic modelling supported a postglacial colonization into western Scotland from northern refugia and a separate colonization route for the English/Welsh populations from southern refugia, with these two groups having been separated for more than ca. 50 Ky. We found cyto‐nuclear discordance at a European scale, with the Scottish populations clustering closely with Baltic population in the mtDNA analysis but not in the nuclear data, and with the Norwegian and Alpine populations displaying the same mtDNA haplotype but being distantly related in the nuclear tree. These findings suggest that neutral processes, primarily drift and regionally distinct pre‐glacial evolutionary histories, are important drivers of genomic divergence in British populations of European whitefish. This sheds new light on the establishment of the native British freshwater fauna after the last glacial maximum.

Temporal and Geographical Variation of Intestinal Ulcers in Grey Seals (Halichoerus grypus) and Environmental Contaminants in Baltic Biota during Four Decades.

Simple SummaryIn the 1970s it was discovered that seal populations in the Baltic Sea had decreased severely due to hunting and high levels of contaminants. Lesions were found in several organs and many of the females became sterile. Since then, most of the organ lesions have decreased and so have the levels of some pollutants. However, ulcers in the large intestines of the grey seals increased in the early 1980s and decreased after the mid-1990s. The aims of this study were to: (1) describe the ulcers and investigate if there is a trend over time that coincides with concentrations of some pollutants in Baltic biota; (2) evaluate the significance of different sea areas in the Baltic, grade of parasite intensity, as well as the sex and age of the seals. The results show that seals with ulcers had, in general, higher parasite intensity. Ulcers were more common in older seals and in the Bothnian Sea. The time trend of ulcers coincides with the trend of certain contaminant levels (BDE-47, PFOS and cadmium). The high prevalence of intestinal ulcers and the high intensity of acanthocephalan parasites appear to be unique to the Baltic population of grey seals.The prevalence of intestinal ulcers and parasites was investigated in 2172 grey seals (Halichoerus grypus) collected in the Baltic Sea and 49 grey seals collected outside the Baltic Sea (i.e., the Atlantic). An increase in frequency of ileocaeco-colonic ulcers was observed in the early 1980s, followed by a decrease in the mid-1990s. At the same time, there was an increase followed by a decrease in brominated flame retardants, Perfluorooctanesulfonic acid (PFOS) and cadmium levels in herring (Clupea harengus), the most common prey item in Baltic grey seal diet, as well as in another top predator in the Baltic, the common guillemot (Uria aalge). The frequency of intestinal ulcers was significantly related to the intensity of acanthocephalan parasites, the age of the seal and the region of the Baltic Sea. Perforation of the intestinal wall was the cause of death in 26 of the investigated Baltic grey seals. In contrast, none of the investigated Atlantic grey seals had intestinal ulcers. They showed a thin colonic wall and very few acanthocephalan parasites. The high prevalence of intestinal ulcers and the high parasite intensity appear to be unique to the Baltic population of grey seals.

Genetic differentiation in an endangered and strongly philopatric, migrant shorebird

BackgroundPopulations living in fragmented habitats may suffer from loss of genetic variation and reduced between-patch dispersal, which are processes that can result in genetic differentiation. This occurs frequently in species with reduced mobility, whereas genetic differentiation is less common among mobile species such as migratory birds. The high dispersal capacity in the latter species usually allows for gene flow even in fragmented landscapes. However, strongly philopatric behaviour can reinforce relative isolation and the degree of genetic differentiation. The Southern Dunlin (Calidris alpina schinzii) is a philopatric, long-distance migratory shorebird and shows reduced dispersal between isolated breeding patches. The endangered population of the Southern Dunlin breeding at the Baltic Sea has suffered from habitat deterioration and fragmentation of coastal meadows. We sampled DNA across the entire population and used 12 polymorphic microsatellite loci to examine whether the environmental changes have resulted in genetic structuring and loss of variation.ResultsWe found a pattern of isolation-by-distance across the whole Baltic population and genetic differentiation between local populations, even within the southern Baltic. Observed heterozygosity was lower than expected throughout the range and internal relatedness values were positive indicating inbreeding.ConclusionsOur results provide long-term, empirical evidence for the theoretically expected links between habitat fragmentation, population subdivision, and gene flow. They also demonstrate a rare case of genetic differentiation between populations of a long-distance migratory species. The Baltic Southern Dunlin differs from many related shorebird species that show near panmixia, reflecting its philopatric life history and the reduced connectivity of its breeding patches. The results have important implications as they suggest that reduced connectivity of breeding habitats can threaten even long-distance migrants if they show strong philopatry during breeding. The Baltic Southern Dunlin warrants urgent conservation efforts that increase functional connectivity and gene flow between breeding areas.

The Pattern of Mandibular Third Molar Impaction and Assessment of Surgery Difficulty: A Retrospective Study of Radiographs in East Baltic Population.

Classifications of impacted teeth allow defining the type and degree of retention, as well as assessing the degree of difficulty of the procedure. The aim of this study was to conduct retrospective analysis of the degree of retention and difficulty in the surgical removal of impacted mandibular third molars in the clinical material of the Department of Oral Surgery in 2013–2018. This study included 1585 dental panoramic radiographs of patients of the Department of Oral Surgery, who reported in 2013–2018, in order to perform surgical removal of the impacted mandibular third molar. Based on dental panoramic radiographs, the degree of retention was determined based on classifications according to Winter, according to Pell and Gregory, according to Tetsch and Wagner, and according to Asanami and Kasazaki. The difficulty of the procedure was also assessed based on the Pederson index. The most common types of lower wisdom tooth impaction are as follows: in Winter’s classification, mesial-angular impaction; in Tetsch and Wagner’s classification, oblique medial-angular impaction; in Pell and Gregory’s classification, impaction grade 2A; and in Asanami and Kasazaki’s classification, 3A and anterior inclination. In most cases of surgical removal of an impacted tooth, the anticipated difficulty of the procedure was rated as very difficult.

Sudovians in Sambia in the 13th–14th centuries

The aim of the proposed work is to ascertain, based on archeological data and written sources, the presence of individuals of the easternmost tribe from the community of the Western Balts — Sudins/Yotvingians. Both scien-tific data from old German excavations and the latest archaeological research in the Zelenogradsk district of the Kaliningrad region are introduced into the scientific discourse. There are no funeral monuments of the Teutonic Order in the territory of the ‘Sudovian corner’ (Lat. Campus Sudowitarum) in the northwestern part of the Sambia peninsula. Ethnographic data on this part of the Amber Coast, provided by the local history manuscripts of the 16th–17th c., include data on the West Baltic population of Western Sambia without actual confirmation of its tribal affiliation. In fact, authors of Polish written sources of the Order time do not draw distinction between the Sudins and Prussians either. Individual burials of male warriors and women with features characteristic of the Sudovian funeral rituals were found at the Prussian burial grounds of the Northern Sambia. Anthropological data confirm this conclusion. In the eastern part of the Prussian tribal area, occupied by the Prussians in the pre-Order times, according to the dating of the burial grounds, two burials with spearheads were encountered amongst the com-plexes of the 14th c., which can be tentatively associated with bearers of the Sudovian traditions. The low repre-sentation of the Sudovian burials at Prussian burial grounds attests to the fact that the Order authorities could have appointed individual representatives of the Sudovian aristocracy, who sided with the conquerors, in order to strengthen the Order in the local polcas (volosts). Using the linguistic and cultural closeness with the Sembians, these Sudins possessed military power (presence of spearheads in the burials, with the common absence of weapons in the Prussian community graves) and could have been collecting taxes on behalf of the Order (the presence of a Western European moneybag in burial Ve-161). The seemingly unnatural presence of the Baltic warriors in the service of the Teutonic Order is symbolized by the decoration of the buckle from burial Ve-161, which bears the coat of arms of the Order and a stylized image of the mythical companion of God Perkuno — the sacred goat, an object of the Prussian sacrifices, presented here as a symbol of the native spiritual traditions.

Growth variation of Atlantic salmon Salmo salar at sea affects their population-specific reproductive potential

Understanding the processes shaping the dynamics of anadromous fish populations is essential for their management and conservation. Yet, little is known about how variation in performance at sea affects their population dynamics. Here we show that variation in body growth at sea contributes to explaining variation in the reproductive potential for 2 Atlantic salmon Salmo salar populations, but to a varying extent. To this end, we assembled data collected during 50 yr for 2 Baltic salmon populations of hatchery origin, including annually released smolts, survival at sea estimates, size-specific growth at sea, annual length distributions of returning adult females and their reproductive potential. The regression models fitted to explain the reproductive potential of our 2 study populations improved when growth at sea was included as an explanatory variable, in addition to smolt year class abundance and estimates of their survival at sea. This link between body growth at sea and population-level reproductive potential suggests that growth at sea can be important to consider when resolving variation in recovery and dynamics among salmon populations sharing the same sea.