Pungitius Pungitius Research Articles

Effect of osmotic stress on protein concentration and antioxidant enzymes activity in the organism of nine-spined stickleback Pungitius pungitius (Gasterosteidae) from the White Sea Basin

The life cycle of P. pungitius (Linnaeus, 1758) includes migrations from the open sea to coastal and freshwater biotopes which are accompanied by osmotic shock and following oxidative stress in fish. The complex multilevel antioxidant system (AOS) includes low-molecular compounds and specific enzymes and protects cells from reactive oxygen species, hydrogen peroxide, and hydroperoxides generated in excess. To study the response of AOS components to oxidative stress caused by acute salinity changes, nine-spined stickleback juveniles from the White Sea estuary were alternately exposed to hypo- and hyperosmotic conditions. In the tissues of stickleback transferred from saltwater to freshwater for 1 and 24 hours a decrease in water-soluble protein concentration and catalase activity was shown. The increased guaiacol-dependent peroxidase activity in estuary fish successively exposed to fresh and saltwater for 24 hours was also observed. Under studied exposures, no changes in the activities of superoxide dismutase and glutathione S-transferase were detected. The involvement of AOS enzymes, particularly neutralizing hydrogen peroxide by the peroxidase-dependent pathway, in the response to acute changes in ambient salinity was described in White sea P. pungitius for the first time. The results of our study provide the new data on the AOS response to hypo- and hyperosmotic stress in euryhaline fish species. The obtained data could be used in predicting the possibility of industrial fish farming in the White Sea-Barents basin.

Feeding Features of the Nine-Spined Stickleback Pungitius pungitius (Gasterosteidae) In Water Bodies of the North-West of Russia

The diet of the nine-spined stickleback Pungitius pungitius has been studied in two water bodies in the north-west of Russia: in the subarctic lake Krivoe (Karelia) and the estuary of the Neva River (Leningrad Oblast). Diptera larvae (Chironomidae, Ceratopogonidae, Simuliidae, and Limoniidae) and planktonic crustaceans formed the basis of the food bolus of fish; however, their abundance and weight ratios differed in the studied water bodies. The seasonal changes of the dominant groups of food objects of the stickleback of Lake Krivoe have been revealed. Additionally to invertebrates and fish eggs, which form the basis of the stickleback diet in winter season, aquatic mosses as well as filamentous and diatom algae present in the fish diet in summer. The comparison of the nitrogen isotope composition of the muscles of stickleback, perch, and invertebrates shows that the stickleback of Lake Krivoe occupies the third trophic level, approaching predatory fish in δ15N values (5.2–8.6‰). A specific feature of the diet patterns of P. pungitius is the transition from a diverse diet of the summer–autumn period to a monotrophic animal diet (chironomid larvae and fish eggs) of the under-ice winter–spring period.

EDNA Metabarcoding Analyses of Diet in Yellow-Billed Loons of Northern Alaska

Environmental DNA is a burgeoning tool used to address wide-ranging scientific questions, including determining diets of difficult-to-sample predators. Loons are large piscivorous diving birds that capture and consume prey underwater, making it nearly impossible to visually determine their diet via observation alone. Identifying species' diets is important for understanding basic life history traits, and revealing key prey species can clarify species' roles in complex trophic webs, aid in understanding population and community dynamics, and help identify critical habitat for protection. Current information about loon diet is largely anecdotal, and traditional non-observational methods for quantifying loon diet have limitations. Analysis of eDNA from loon feces may provide biologists with a non-invasive technique for determining diet without negative sampling effects, and with increased resolution as compared to other techniques. We surveyed lakes in two areas of northern Alaska for Yellow-billed Loons (Gavia adamsii). Loon fecal samples were collected opportunistically from latrine sites without disturbing any animals and analyzed using novel marker sets to determine loon species and diet. Fish species were detected in all fecal samples, the most common being Alaska blackfish (Dallia pectoralis), and ninespine stickleback (Pungitius pungitius). This research demonstrates that eDNA metabarcoding analyses of loon fecal samples can determine the specific loon species that deposited the feces and characterize the piscine portion of their diet with limited disturbance to the animals.

Evaluating Dermal Bone as a Novel Source of Endocrine Information in Ninespine and Threespine Stickleback Fish.

Monitoring the physiology of small aquatic and marine teleost fish presents challenges. Blood samples, often the first choice for endocrinologists, can be difficult or even impossible to obtain and alternative matrices currently used for hormone analyses do not occur in fishes (e.g., hair, feathers etc.) or are not easily collected from small aquatic organisms (e.g., urine and feces). Some teleosts, however, have enlarged bony dermal elements that possibly accumulate and store steroid hormones in physiological relevant concentrations. Both threespine stickleback (Gasterosteus aculeatus) and ninespine stickleback (Pungitius pungitius) have a series of external, lateral bony plates, dorsal spines, and a pair of pelvic spines attached to the pelvic girdle. We investigated if cortisol, the primary circulating glucocorticoid in teleosts, could be extracted from stickleback dermal bone and quantified using a commercially available enzyme immunoassay (EIA). We successfully validated a cortisol EIA for dermal bone extracts, determined that cortisol was detectable in both species, and found that dermal bone cortisol levels significantly correlated with cortisol levels in whole body homogenate. Ninespine stickleback had significantly higher dermal bone cortisol concentrations than threespine stickleback and female threespine stickleback tended to have over twice the mean dermal bone cortisol concentration than males. Because both stickleback species are widely used for ecotoxicological studies, using dermal bone as a source of endocrine information, while leaving the body for contaminant, genomic, histological, and stable isotope analyses, could be a powerful and parsimonious tool. Further investigation and physiological validations are necessary to fully understand the utility of this new sample matrix.

Habitat selection behaviour of Pungitius kaibarae (Gasterosteidae) in the presence of the visual predator Anguilla japonica (Anguillidae)

Our study deals with how the short nine-spine stickleback Pungitius kaibarae uses visual cues to select among habitats, thereby reducing predation pressure from the Japanese eel Anguilla japonica. We examined the behaviour of P. kaibaraein selecting four habitats (water weed, sandy, rocky and open water) under the presence/absence of A. japonica. Using video tracking technology, we found that in the presence of A. japonica, sticklebacks preferred specific refuge patches, such as waterweed and rocks, over open water with a sandy bottom. Thus, our investigation demonstrated the importance of habitat structures in evoking escape behaviour. We discuss the importance of this bold behaviour patterns of the prey fish.Keywords: Bold behaviour, Stickleback, Eel, Swimming speed, Video tracking

Effect of salinity on nest building behaviour in the nine-spined stickleback Pungitius sinensis.

The authors evaluated the adaptability of male nine-spined sticklebacks (Pungitius sinensis) at three salinity levels (0, 5 and 10psu) by comparing nest building success rates with nest structures. Successful nest building decreased as salinity increased. In addition, nests built in fresh water (i.e., 0 psu) were glued together, whereas those built in brackish water (5 and 10psu) broke easily and fell from the nest site to the gravel bottom. Based on these findings, the authors suggest that P. sinensis adapts to freshwater environments.

Investigating effects of climate-induced changes in water temperature and diet on mercury concentrations in an Arctic freshwater forage fish

The amount of mercury (Hg) in Arctic lake food webs is, and will continue to be, affected by rapid, ongoing climate change. At warmer temperatures, fish require more energy to sustain growth; changes in their metabolic rates and consuming prey with potentially higher Hg concentrations could result in increased Hg accumulation. To examine the potential implications of climate warming on forage fish Hg accumulation in Arctic lakes, we quantified growth and Hg accumulation in Ninespine Stickleback Pungitius pungitius under different temperature and diet scenarios using bioenergetics models. Four scenarios were considered that examined the role of climate, diet, climate × diet, and climate × diet × elevated prey Hg. As expected, annual fish growth increased with warmer temperatures, but growth rates and Hg accumulation were largely diet dependent. Compared to current growth rates of 0.3 g⋅y−1, fish growth increased at least 200% for fish consuming energy-dense benthic prey and decreased at least 40% for fish consuming pelagic prey. Compared to baseline levels, the Hg burden per kilocalorie of Ninespine Stickleback declined up to 43% with benthic consumption – indicating strong somatic growth dilution – but no more than 4% with pelagic consumption; elevated prey Hg concentrations led to moderate Hg declines in benthic-foraging fish and Hg increases in pelagic-foraging fish. Bioenergetics models demonstrated the complex interaction of water temperature, growth, prey proportions, and prey Hg concentrations that respond to climate change. Further work is needed to resolve mechanisms and rates linking climate change to Hg availability and uptake in Arctic freshwater systems.

Complex population history affects admixture analyses in nine-spined sticklebacks.

Introgressive hybridization is an important process in evolution but challenging to identify, undermining the efforts to understand its role and significance. On the contrary, many analytical methods assume direct descent from a single common ancestor, and admixture among populations can violate their assumptions and lead to seriously biased results. A detailed analysis of 888 whole-genome sequences of nine-spined sticklebacks (Pungitius pungitius) revealed a complex pattern of population ancestry involving multiple waves of gene flow and introgression across northern Europe. The two recognized lineages were found to have drastically different histories, and their secondary contact zone was wider than anticipated, displaying a smooth gradient of foreign ancestry with some curious deviations from the expected pattern. Interestingly, the freshwater isolates provided peeks into the past and helped to understand the intermediate states of evolutionary processes. Our analyses and findings paint a detailed picture of the complex colonization history of northern Europe and provide backdrop against which introgression and its role in evolution can be investigated. However, they also expose the challenges in analyses of admixed populations and demonstrate how hidden admixture and colonization history misleads the estimation of admixture proportions and population split times.

Relaxed risk of predation drives parallel evolution of stickleback behavior.

The occurrence of similar phenotypes in multiple independent populations derived from common ancestral conditions (viz. parallel evolution) is a testimony of evolution by natural selection. Parallel evolution implies that populations share a common phenotypic response to a common selection pressure associated with habitat similarity. Examples of parallel evolution at genetic and phenotypic levels are fairly common, but the driving selective agents often remain elusive. Similarly, the role of phenotypic plasticity in facilitating early stages of parallel evolution is unclear. We investigated whether the relaxation of predation pressure associated with the colonization of freshwater ponds by nine-spined sticklebacks (Pungitius pungitius) likely explains the divergence in complex behaviors between marine and pond populations, and whether this divergence is parallel. Using laboratory-raised individuals exposed to different levels of perceived predation risk, we calculated vectors of phenotypic divergence for four behavioral traits between habitats and predation risk treatments. We found a significant correlation between the directions of evolutionary divergence and phenotypic plasticity, suggesting that divergence in behavior between habitats is aligned with the response to relaxation of predation pressure. Finally, we show alignment across multiple pairs of populations, and that relaxation of predation pressure has likely driven parallel evolution of behavior in this species.

Intergeneric hybridization of two stickleback species leads to introgression of membrane-associated genes and invasive TE expansion

Interspecific hybridization has occurred relatively frequently during the evolution of vertebrates. This process usually abolishes reproductive isolation between the parental species. Moreover, it results in the exchange of genetic material and can lead to hybridogenic speciation. Hybridization between species has predominately been observed at the interspecific level, whereas intergeneric hybridization is rarer. Here, using whole-genome sequencing analysis, we describe clear and reliable signals of intergeneric introgression between the three-spined stickleback (Gasterosteus aculeatus) and its distant mostly freshwater relative the nine-spined stickleback (Pungitius pungitius) that inhabit northwestern Russia. Through comparative analysis, we demonstrate that such introgression phenomena apparently take place in the moderate-salinity White Sea basin, although it is not detected in Japanese sea stickleback populations. Bioinformatical analysis of the sites influenced by introgression showed that they are located near transposable elements, whereas those in protein-coding sequences are mostly found in membrane-associated and alternative splicing-related genes.

Deciphering Eurasian otter (Lutra lutra L.) and seal (Phoca vitulina L.; Halichoerus grypus F.) diet: Metabarcoding tailored for fresh and saltwater fish species.

Long-lived top predators shape biodiversity structure in their ecosystems and predator-prey interactions are critical in decoding how communities function. Studies on the foraging ecology of seals and Eurasian otters in Western Europe are outdated and most studies solely performed traditional hard part analysis. Molecular metabarcoding can be used as an innovative noninvasive diet analysis tool, which has proven efficient and complementary to hard part analysis, however, lacking application in the wider North Sea area. In this study, DNA from digesta, collected between 2014-2020, were used to identify fish species in the diet of 47 Eurasian otters, 54 harbour seals and 21 grey seals by applying a next-generation metabarcoding approach. A newly designed 16S rRNA primer, providing the best coverage of >130 local marine and freshwater fish species, was used to amplify prey DNA from seal scats and otter gut content sampled from the North Sea and regional freshwater bodies. Frequent fish species included tench, ninespine stickleback and white bream in otters; hooknose and common roach in grey seals and Pleuronectidae and sand gobies in harbour seals. Bipartite network analysis showed a strong overlap of harbour and grey seal diets. Otter diet intersected with both seal species in terms of freshwater species. This study provides new knowledge about dietary composition and community assemblage of fish prey in otters and seals in the North Sea and regional freshwaters, and a new molecular tool to elucidate predator-prey interactions and interspecies competition in complex and changing ecosystems under pressure from anthropogenic activities.

Attempting genetic inference from directional asymmetry during convergent hindlimb reduction in squamates.

Loss and reduction in paired appendages are common in vertebrate evolution. How often does such convergent evolution depend on similar developmental and genetic pathways? For example, many populations of the threespine stickleback and ninespine stickleback (Gasterosteidae) have independently evolved pelvic reduction, usually based on independent mutations that caused reduced Pitx1 expression. Reduced Pitx1 expression has also been implicated in pelvic reduction in manatees. Thus, hindlimb reduction stemming from reduced Pitx1 expression has arisen independently in groups that diverged tens to hundreds of millions of years ago, suggesting a potential for repeated use of Pitx1 across vertebrates. Notably, hindlimb reduction based on the reduction in Pitx1 expression produces left‐larger directional asymmetry in the vestiges. We used this phenotypic signature as a genetic proxy, testing for hindlimb directional asymmetry in six genera of squamate reptiles that independently evolved hindlimb reduction and for which genetic and developmental tools are not yet developed: Agamodon anguliceps, Bachia intermedia, Chalcides sepsoides, Indotyphlops braminus, Ophisaurus attenuatuas and O. ventralis, and Teius teyou. Significant asymmetry occurred in one taxon, Chalcides sepsoides, whose left‐side pelvis and femur vestiges were 18% and 64% larger than right‐side vestiges, respectively, suggesting modification in Pitx1 expression in that species. However, there was either right‐larger asymmetry or no directional asymmetry in the other five taxa, suggesting multiple developmental genetic pathways to hindlimb reduction in squamates and the vertebrates more generally.

Juvenile Fish Associated With Pondweed and Charophyte Habitat in the Curonian Lagoon

Submerged macrophytes are essential elements of sublittoral ecosystems to maintain a diverse fish fauna. The aim of this study was to assess juvenile fish associated with macrophyte habitats in the Curonian Lagoon by means of modified pop net method. We focused on two dominant littoral habitats with different structure (pondweed and charophyte stands). The pop nets sampling was carried out on two study sites located in the freshwater and oligohaline part of the lagoon in July and September 2019-2020. Our upgraded pop nets reduced the risk of under sampling and are recommended for monitoring fishes since this method has relatively low disturbance on fish behavior and on the habitat itself. The most efficient time of sampling with pop nets in shallow macrophyte habitats is at night, where at least 4 samples collected are sufficient to represent the biggest part (> 70%) of the fish assemblage, but the sampling covering different times of day is recommended. In total, 14 juvenile species were recorded, where perch and European roach dominated (respectively 48% and 24%). Half of the species (8) were associated with macrophyte stands, although water salinity and temperature were the most important factors explaining the variance of fish abundance followed by the sampling time and the biomass of macrophytes. Based on the abundance and the duration of species within these habitats, European roach, nine-spined and three-spined stickleback were mainly associated with the pondweed biomass and stands, while spined loach, round goby, perch, ruffe and gudgeon were mainly associated with the charophyte biomass and stands. The increase of charophyte stands since 2005 affected the fish assemblage where it should have enhanced the abundance of perch, ruffe, spined loach and partly round goby.

Age-dependent genetic architecture across ontogeny of body size in sticklebacks.

Heritable variation in traits under natural selection is a prerequisite for evolutionary response. While it is recognized that trait heritability may vary spatially and temporally depending on which environmental conditions traits are expressed under, less is known about the possibility that genetic variance contributing to the expected selection response in a given trait may vary at different stages of ontogeny. Specifically, whether different loci underlie the expression of a trait throughout development and thus providing an additional source of variation for selection to act on in the wild, is unclear. Here we show that body size, an important life-history trait, is heritable throughout ontogeny in the nine-spined stickleback (Pungitius pungitius). Nevertheless, both analyses of quantitative trait loci and genetic correlations across ages show that different chromosomes/loci contribute to this heritability in different ontogenic time-points. This suggests that body size can respond to selection at different stages of ontogeny but that this response is determined by different loci at different points of development. Hence, our study provides important results regarding our understanding of the genetics of ontogeny and opens an interesting avenue of research for studying age-specific genetic architecture as a source of non-parallel evolution.

Context-dependent parasite infection affects trophic niche in populations of sympatric stickleback species.

How parasites alter host feeding ecology remains elusive in natural populations. A powerful approach to investigate the link between infection and feeding ecology is quantifying unique and shared responses to parasite infection in related host species within a common environment. Here, 9 pairs of sympatric populations of the three-spined and nine-spined stickleback fishes were sampled across a range of freshwater and brackish habitats to investigate how parasites alter host feeding ecology: (i) biotic and abiotic determinants of parasite community composition, and (ii) to what extent parasite infection correlates with trophic niche specialization of the 2 species, using stable isotope analyses (δ15N and δ13C). It was determined that parasite community composition and host parasite load varied among sites and species and were correlated with dissolved oxygen. It was also observed that the digenean Cyathocotyle sp.'s abundance, a common directly infecting parasite with a complex life cycle, correlated with host δ13C in a fish species-specific manner. In 6 sites, correlations were found between parasite abundance and their hosts' feeding ecology. These effects were location-specific and occasionally host species or host size-specific. Overall, the results suggest a relationship between parasite infection and host trophic niche which may be an important and largely overlooked ecological factor. The population specificity and variation in parasite communities also suggest this effect is multifarious and context-dependent.

Length–weight relations of ten freshwater fish species (Actinopterygii) from Abashiri River basin, eastern Hokkaido, Japan

Length–weight relations (LWRs) were estimated for ten freshwater fish species such as gin-buna, Carassius langsdorfii Temminck et Schlegel, 1846; lake minnow, Rhynchocypris percnura (Pallas, 1814); Siberian loach, Barbatula toni (Dybowski, 1869); Japanese smelt, Hypomesus nipponensis McAllister, 1963; masu salmon, Oncorhynchus masou (Brevoort, 1856); rainbow trout, Oncorhynchus mykiss (Walbaum, 1792); whitespotted char, Salvelinus leucomaenis (Pallas, 1814); ninespine stickleback, Pungitius pungitius (Linnaeus, 1758); hana-kajika, Cottus nozawae Synder, 1911; and a species of goby Rhinogobius sp. Specimens were collected once a month except in the snow season from the Abashiri River basin, eastern Hokkaido, between June 2007 and November 2011. Fishes were captured by an electrofishing device (Smith–Root Inc., Model 12-b). The estimated allometric coefficient b values ranged from 2.790 (ninespine stickleback) to 3.294 (hana-kajika), and r2 values ranged from 0.772 (lake minnow) to 0.994 (goby). All the LWRs were highly significant, with P < 0.001. Besides, the study provides the first estimates of LWRs for the Siberian loach, Japanese smelt, masu salmon, whitespotted char, hana-kajika, and the goby.

Species Composition and Features of Fish Biology of Thermal Mineral Springs of the Arctic River Gilmimliveem (East Chukotka)

The fish fauna of the Gilmimliveem River (the Bering Sea basin) includes five taxa of species and subspecies ranks: Arctic grayling Thymallus arcticus signifer, resident (landlocked) dwarf Dolly Varden trout Salvelinus malma, relict three-spined stickleback Gasterosteus cf. aculeatus, the nine-spined stickleback Pungitius pungitius, and the western slimy sculpin Cottus cognatus cognatus. Arctic grayling and nine-spined stickleback were found for the first time. Two rare Beringian subspecies are recorded (T. arcticus signifier and C. cognatus cognatus) and a local endemic of Northeast Asia (G. cf. aculeatus). A morphological description, some features of the biology and current state of populations of freshwater fish of a unique ecosystem of thermal mineral springs of the Gilmimliveem River are presented for the first time. The linear growth of these fish on the Chukchi Peninsula of the Russian Arctic (the northeastern edge of the Asian continent) is discussed.

Strong assortative mating in ninespine stickleback Pungitius tymensis demonstrated in no-choice mating trials between pairs of three congeneric species

Strong assortative mating in ninespine stickleback <i>Pungitius tymensis</i> demonstrated in no-choice mating trials between pairs of three congeneric species

Comparing genome scans among species of the stickleback order reveals three different patterns of genetic diversity.

Comparing genome scans among species is a powerful approach for investigating the patterns left by evolutionary processes. In particular, this offers a way to detect candidate genes that drive convergent evolution. We compared genome scan results to investigate if patterns of genetic diversity and divergence are shared among divergent species within the stickleback order (Gasterosteiformes): the threespine stickleback (Gasterosteus aculeatus), ninespine stickleback (Pungitius pungitus), and tubesnout (Aulorhynchus flavidus). Populations were sampled from the southern and northern edges of each species’ range, to identify patterns associated with latitudinal changes in genetic diversity. Weak correlations in genetic diversity (F ST and expected heterozygosity) and three different patterns in the genomic landscape were found among these species. Additionally, no candidate genes for convergent evolution were detected. This is a counterexample to the growing number of studies that have shown overlapping genetic patterns, demonstrating that genome scan comparisons can be noisy due to the effects of several interacting evolutionary forces.

Editorial 2022

Editorial 2022