Search Results (20)

A subarctic Norwegian watercourse is known for its population of threespine sticklebacks (Gasterosteus aculeatus Linnaeus 1758) with unusual pelvic spine polymorphism; the upper lake contains a mixture of specimens that are normal-spined, asymmetric-spined, and spineless. In contrast, the downstream lakes and the nearby marine site contain only the normal spined morph. We investigated the maternal-line genetic structure in the watercourse using mitogenomics. A total of 242 sticklebacks representing two lakes and a marine site were assessed based on individual and pooled DNA sequencing. While two distinct mitogenome clades were detected in the upper lake (Lake Storvatnet), only one of these clades was present in the downstream lake. The marine site pooled DNA sample, however, contained several mitogenome haplotypes. We present mitogenome sequence features that include gene-specific single nucleotide polymorphisms, molecular phylogeny, and genetic differentiation assessments based on pairwise comparisons of pooled population samples from each site. The Lake Storvatnet mitogenomes belong to two distinct Euro-North American (ENA) clades; one of the ancestral lineages likely corresponds to the original maternal lineage in the watercourse, and the other was introduced more recently. We hypothesize that the second invader carried nuclear genomic features responsible for the observed present-day pelvic spine polymorphism in Lake Storvatnet. Full article

Anthropogenic activities increase turbidity in coastal marine environments globally, and turbidity is particularly caused by eutrophication. Turbidity is a measurement of the scattering and absorption of light by suspended matter in water. An increase in turbidity influences visual predators and affects community structures and whole ecosystems. The three-spined stickleback (Gasterosteus aculeatus) is a widespread species in the northern hemispheric Pacific and Atlantic oceans. It is a visual predator and, therefore, a very well-suited species for studying the effects of increasing turbidity on foraging behaviour and activity. Sticklebacks used for this study were from an aquarium in the North Sea Oceanarium. They have been in the aquarium for around two months and were originally collected in a highly eutrophicated marine fjord system. They were individually placed in an observation aquarium, fed with krill, given 10 min to forage, and observed by video cameras. The video films were analysed to study stickleback predation behaviour. Experiments were repeated with four different turbidity treatments, ranging from a mean of 0.034 up to 10 NTU (nephelometric turbidity unit). Bentonite clay was used as a turbidity-increasing substance. A statistically significant difference in foraging behaviour and activity between the turbidity treatments was observed. The test subjects were found to lunge less for prey and had a higher feeding latency with increasing turbidity. Additionally, they were less active with increasing turbidity. The behavioural instability estimated as a variation in feeding latency increased with increasing turbidity but decreased at the highest turbidity value. Our study indicates an effect of turbidity-increasing events on the behaviour of the three-spined stickleback and potentially also other similar visual predators. Full article

The spatial and temporal variability in the dietary preferences of juvenile three-spined stickleback Gasterosteus aculeatus were studied across the typical coastal habitats of Keret Archipelago, Kandalaksha Bay(the White Sea). The sampling of fish using a beach seine was conducted in the late July–early August period and in late August. Additionally, zooplankton samples were collected to conduct a quantitative assessment of the abundance of potential prey items. The similarity percentage (SIMPER) analysis was applied to the data obtained from the stomach content and revealed the five planktonic taxa most prominently contributing to the diet of juvenile sticklebacks. Among these, the copepod Temora longicornis was the most important prey item at marine sites, while Acartia longiremis dominated the diet of fish in the marine lagoon. The calculation of the selectivity index revealed that some taxa (such as A. longiremis) were always avoided by juvenile fish, whereas the selectivity of some taxa increased in late August. In general, juvenile sticklebacks demonstrated a pronounced individual variation in their selectivity, even when a particular prey item was selected positively during the whole period of study. Our data highlight that despite the predominant consumption of easily available prey by juvenile sticklebacks, they demonstrate taxonomic- and size-specific prey selectivity. Full article

The warming and acidification of surface waters as predicted by the IPCC leads aquatic species to face major multifaceted changes in their environment. Although teleosts have efficient regulatory systems to cope with these changes, such changes clearly have the potential to impact their physiological functions. Hence, it is crucial to estimate the ability of teleost fishes to cope with multi-stresses to predict how they will deal with future environments. In this context, we investigated the joint effect of warming and acidification on three-spined stickleback (Gasterosteus aculeatus) from the juvenile stage to adulthood, focusing on parameters linked to growth, sexual maturation, and reproduction. Juvenile sticklebacks were split in 2 climate scenarios: a “Current” scenario corresponding to the current seasonal physico-chemical parameters of the water of the “Rade de Brest” in France, and a “RCP8.5” scenario with a warming of 3 °C and an acidification of 0.4 pH units. After 7 months, fish in the RCP8.5 scenario reached the same size and mass as those in the Current scenario, but they needed greater amounts of food to reach satiety. Furthermore, the mortality rate over the experiment was higher in the RCP8.5 scenario. Muscle lipid content, an indicator of energy reserves, was lower in females in the RCP8.5 scenario, suggesting an increased need for energy to maintain homeostasis and other physiological functions or a divergence in energy allocation strategy. Moreover, females exhibited lower sexual maturation and egg quality under the RCP8.5 scenario, which could have contributed to the lower fertilisation rate observed. Males were more resilient to the RCP8.5 scenario, exhibiting only a trend for lower kidney somatic index scores. Altogether, these results suggest a delay and/or an inhibition of gametogenesis and maturation in fish in warmed and acidified waters. The analysis of blood sex steroid concentrations, brain gene expression profiles, and physiological indexes did not allow us to discriminate between a delay and an inhibition of maturation in the RCP8.5 scenario. Overall, these findings clearly indicate that there is a long-term global impact of combined acidification and warming on the mortality and reproductive performance of three-spined stickleback. Full article

Differentiation in the defensive armor of the threespine stickleback, Gasterosteus aculeatus, is caused by predator-driven divergent selection. Most studies considered armor traits related to swimming behavior, hence combining pre- and post-capture responses to gape-limited predators. Here, we focus exclusively on the defensive complex (DC), the post-capture predator defense. This complex consists of a series of bony elements surrounding the anterior part of the abdomen. Relaxation from predation pressure not only drives reduction of bony elements but is also expected to increase asymmetry in the DC. To test this hypothesis, we used four Austrian freshwater populations that differed distinctly in the formation of the DC. We found significant left–right asymmetries in the DC in the population with a distinctly reduced DC and, surprisingly, also in the population with a significantly enhanced DC. These populations occur in vastly different habitats (stream and lake) characterized by distinct regimes of gape-limited predators (none vs. many). Apparently, both a shift to very low and very high pressure by gape-limited predators can boost asymmetry. We conclude that greater asymmetries in the two populations at the opposite ends of the predatory gradient result from an ongoing process of adaptation to decreased or increased environmental stress. Full article

Submersion in the anaesthetic MS-222 is a well-established and effective method used during the euthanasia of fish, but the consequences of treatment with this anaesthetic for mitochondrial respiration are yet to be established. This is important to evaluate, as an increasing amount of research is conducting high-resolution respirometry to measure respiration across multiple species of fish, including looking at thermal sensitivity and mitochondrial responses to the warmer temperatures faced with climate change. Analysis often occurs after euthanasia with MS-222 without knowledge of how MS-222 itself affects any measured parameters of mitochondrial respiration, leaving potential for a misinterpretation of results. Here, high-resolution respirometry was conducted to explore how MS-222 affects oxidative phosphorylation in the brain and skeletal muscle of the three-spined stickleback, Gasterosteus aculeatus, which is a model species in evolutionary ecology. In the brain, differences in respiration were observed between three-spined sticklebacks euthanised with MS-222 and those where no anaesthetic was implemented. No differences between treatments were observed in the skeletal muscle, although variation between individuals was high and oxygen flux was lower than in the brain. Overall, this study highlights the need for a consistent method of euthanasia when conducting high-resolution respirometry in fish, as MS-222 may alter measures of oxidative phosphorylation. Full article

Studies of dietary preferences of migratory species are of great importance as these species connect food webs of habitats across the migration route and thus represent trophic relationships between the spatially disjointed communities. Here we described the dietary preferences of threespine stickleback G. aculeatus in the White Sea during the spawning season using stable isotope and stomach content analyses. The two analyses suggested that during the spawning season, when sticklebacks spend the majority of their time inshore, their diet consists mostly of benthic species, while at the beginning of the spawning season when fish migrating from the offshore were feeding on plankton. Additionally, we demonstrated that stickleback eggs contributed greatly to the diet of both male and female fish. Using Bayesian mixing modeling, we showed that dietary preferences in females were broader than in males, and more variable during the spawning season. While guarding their nests, males fed almost exclusively on eggs. Both stomach contents and isotope signatures demonstrate that by the end of the spawning season sticklebacks again increase the consumption of plankton. Isotope analysis proved to be a more reliable tool to trace this change than stomach content analysis. Our results show that stable isotope and stomach content analyses are complementary in understanding seasonal changes in the dietary composition of stickleback. Full article

The threespine stickleback is a freshwater fish listed as endangered in Portugal, near the southern limit of the species global distribution. However, few measures have been proposed aiming at the conservation of this species in suboptimal environments. From existing databases and specific sampling campaigns, we obtained occurrence data of threespine stickleback for a total of 646 sites. The occurrence data, together with 15 environmental macrohabitat predictors, were used to model the potential distribution of the species using an ensemble of species distribution models. Through the results of our final ensemble, we project that the threespine stickleback occurs predominantly at lower stretches of river systems, where sandy substrate is dominant and flow is higher. Within this region, sticklebacks are also more likely to occur in sites with high levels of rainfall in the driest month, thus avoiding locations with high potential for drying during summer. The species also tends to avoid steep slope areas with high levels of annual precipitation. Based on our results, a map of the species probability of occurrence was generated and river sections were categorized into levels according to their importance for the species’ conservation. Full article

A total of 205 COI sequences and 310 cyt b sequences of the threespine stickleback (Gasterosteus aculeatus) from basins of all seas throughout the vast range of this species were analyzed. Median networks of haplotypes constructed in this study, combined with the results of reconstruction of paleogeographic conditions, led to the conclusion that the threespine stickleback emerged as a species in the Pacific Ocean basin and spread to Europe from the south, populating the system of water bodies that existed in the Oligocene. The main water body was the Paratethys Ocean (Sea), which existed 5–34 Mya. In the area of the modern North Sea, stickleback populations, part of which later migrated to the eastern and western coasts of North America, gave rise to the group of haplotypes that has the widest distribution in northern Europe. The stickleback populations belonging to the lineage that dispersed along the Arctic and western coasts of North America displaced the carriers of the haplotypes of the ancient phylogenetic lineage that inhabited the Pacific coast. The ancestors of G. wheatlandi dispersed from the Pacific to the Atlantic Ocean via the Arctic to meet G. aculeatus, which circled the globe from east to west. Full article

The conservation of fish biodiversity requires reliable information on their distribution and habitat use, especially of endemic species that generally occur in restricted geographic areas and specific habitats. This is the case of threespine stickleback (G. aculeatus L.), that is a small freshwater fish listed as Endangered (EN) in Portugal, which represents the southern limit of the species global distribution. The monitoring and conservation of populations placed near to the species distribution limits is very important because in these places, small environmental changes can lead to the significant decline of local populations. However, due to the lack of knowledge about its regional distribution, ecology, and macrohabitat preferences, few measures have been proposed aiming the conservation of this species. This project aimed to identify which macro-scale environmental factors determine regional distribution of G. aculeatus, to predict their potential distribution and, therefore, define the most important areas for their protection and conservation. The occurrence data, from existing databases and specific sampling campaigns, together with 15 environmental macrohabitat predictors, were used to model the potential distribution of sticklebacks in Portugal, through an ensemble of species distributions models (SDM). Through the results of our ensemble model, we found that threespine stickleback may occur predominantly at lower stretches of river systems, where sandy substrate is dominant, and flow is higher. Sticklebacks are also more likely to occur in sites with high levels of rainfall in the driest month, thus avoiding locations with high potential for drying during summer, which tend to be common in the Iberian Peninsula. The species also tends to avoid steep slope areas, with high levels of annual precipitation. Based on our results, a probability map of occurrence was generated; from this, some river stretches were categorized into levels according to their importance for the conservation of the species. With the results obtained, it was also possible to identify some atypical populations, occurring in areas with low or null habitat suitability, which need to be further studied, because they must have developed physiological characteristics that allow them to subsist in places that are not conducive to their survival. Full article

Water is impacted by a variety of increasing pressures, such as contaminants, including genotoxic pollutants. The proposed multi-biomarker approach at a sub-individual level gives a complementary indicator to the chemical and ecological parameters of the Water Framework Directive (WFD, 2000/60/EC). By integrating biomarkers of genotoxicity and erythrocyte necrosis in the sentinel fish species the three-spined stickleback (Gasterosteus aculeatus) through active biomonitoring of six stations of the Artois-Picardie watershed, north France, our work aimed to improve the already existing biomarker approach. Even if fish in all stations had high levels of DNA strand breaks, the multivariate analysis (PCA), followed by hierarchical agglomerative clustering (HAC), improved discrimination among stations by detecting an increase of nuclear DNA content variation (Etaing, St Rémy du Nord, Artres and Biache-St-Vaast) and erythrocyte necrosis (Etaing, St Rémy du Nord). The present work highlighted that the integration of these biomarkers of genotoxicity in a multi-biomarker approach is appropriate to expand physiological parameters which allow the targeting of new potential effects of contaminants. Full article

Analysis of zoogeographic, paleogeographic, and molecular data has shown that the ancestors of many fresh- and brackish-water cold-tolerant hydrobionts of the Mediterranean region and the Danube River basin likely originated in East Asia or Central Asia. The fish genera Gasterosteus, Hucho, Oxynoemacheilus, Salmo, and Schizothorax are examples of these groups among vertebrates, and the genera Magnibursatus (Trematoda), Margaritifera, Potomida, Microcondylaea, Leguminaia, Unio (Mollusca), and Phagocata (Planaria), among invertebrates. There is reason to believe that their ancestors spread to Europe through the Paratethys (or the proto-Paratethys basin that preceded it), where intense speciation took place and new genera of aquatic organisms arose. Some of the forms that originated in the Paratethys colonized the Mediterranean, and overwhelming data indicate that representatives of the genera Salmo, Caspiomyzon, and Ecrobia migrated during the Miocene from the region of the modern Caspian through the Araks Strait, which existed at that time. From the Ponto-Caspian and the Mediterranean regions, noble salmon, three-spined stickleback, European pearl mussel, seals, and mollusks of the genus Ecrobia spread to the Atlantic Ocean and colonized the Subarctic and Arctic regions of Europe and North America. Our study indicates that the area of the former Paratethys retains its significance as a center of origin of new species and genera and that it has been the starting point of migration “corridors” up to the present time. Full article

There is a general and solid theoretical framework to explain how the interplay between natural selection and gene flow affects local adaptation. Yet, to what extent coexisting closely related species evolve collectively or show distinctive evolutionary responses remains a fundamental question. To address this, we studied the population genetic structure and morphological differentiation of sympatric three-spined and nine-spined stickleback. We conducted genotyping-by-sequencing and morphological trait characterisation using 24 individuals of each species from four lowland brackish water (LBW), four lowland freshwater (LFW) and three upland freshwater (UFW) sites in Belgium and the Netherlands. This combination of sites allowed us to contrast populations from isolated but environmentally similar locations (LFW vs. UFW), isolated but environmentally heterogeneous locations (LBW vs. UFW), and well-connected but environmentally heterogenous locations (LBW vs. LFW). Overall, both species showed comparable levels of genetic diversity and neutral genetic differentiation. However, for all three spatial scales, signatures of morphological and genomic adaptive divergence were substantially stronger among populations of the three-spined stickleback than among populations of the nine-spined stickleback. Furthermore, most outlier SNPs in the two species were associated with local freshwater sites. The few outlier SNPs that were associated with the split between brackish water and freshwater populations were located on one linkage group in three-spined stickleback and two linkage groups in nine-spined stickleback. We conclude that while both species show congruent evolutionary and genomic patterns of divergent selection, both species differ in the magnitude of their response to selection regardless of the geographical and environmental context. Full article

Much of animal-associated microbiome research has been conducted in species for which little is known of their natural ecology and evolution. Microbiome studies that combine population genetic, environment, and geographic data for wild organisms can be very informative, especially in situations where host genetic variation and the environment both influence microbiome variation. The few studies that have related population genetic and microbiome variation in wild populations have been constrained by observation-based kinship data or incomplete genomic information. Here we integrate population genomic and microbiome analyses in wild threespine stickleback fish distributed throughout western Oregon, USA. We found that gut microbiome diversity and composition partitioned more among than within wild host populations and was better explained by host population genetic divergence than by environment and geography. We also identified gut microbial taxa that were most differentially abundant across environments and across genetically divergent populations. Our findings highlight the benefits of studies that investigate host-associated microbiomes in wild organisms. Full article

The threespine stickleback is a geographically widespread and ecologically highly diverse fish that has emerged as a powerful model system for evolutionary genomics and developmental biology. Investigations in this species currently rely on a single high-quality reference genome, but would benefit from the availability of additional, independently sequenced and assembled genomes. We present here the assembly of four new stickleback genomes, based on the sequencing of microfluidic partitioned DNA libraries. The base pair lengths of the four genomes reach 92–101% of the standard reference genome length. Together with their de novo gene annotation, these assemblies offer a resource enhancing genomic investigations in stickleback. The genomes and their annotations are available from the Dryad Digital Repository (https://doi.org/10.5061/dryad.113j3h7). Full article