Myoxocephalus Scorpius Research Articles

Распределение рыб семейства Cottidae в юго-восточной части Баренцева моря (к западу от о. Долгий)

The distribution of Cottidae species in the southwestern part of the Barents Sea (Pechora Sea) based on materials from ichthyological surveys carried out in the summer of 2010–2023 is shown. Cottidae species were maximum 1.7 % of the total catch. A total of 7 species have been noted. The most abundant Cottidae species in Pechora Sea is arctic staghorn sculpin G. tricuspis (85 % frequency of occurrence), shorthorn sculpin M. scorpius (62 %) and ribbed sculpin T. pingelii (46 %). Values of the total abundance of the Cottidae was diverse: 1.2 to 757.6 ind/km2 and 0.002 to 21.906 kg/km2.

Deep Learning-based marine species detection and classification framework for biomonitoring in the Arctic fjords, Svalbard

The effects of ongoing climate change have caused a poleward shift in the distribution of species due to the rapidly rising water temperatures. This calls for an immediate need to assess and document the extent of climate change-driven animal migrations occurring in the Arctic waters. However, the extreme climatic conditions and the remoteness of the region makes biomonitoring tedious in the Arctic ecosystem. The present study puts forward a deep learning-based analysis of a large underwater video dataset that was captured from the Arctic region. The dataset was acquired using underwater cameras mounted on custom-made stainless-steel frames. The video footages were collected over a period of 26 days from the Kongsfjorden- Krossfjorden twin Arctic fjords in Svalbard, Norway. The collected data sets were used to train YOLO-based object detection framework (You Only Look Once) for an automated detection of the organisms. The YOLO model employed for the study was found to be very efficient in classifying the underwater images captured from the region. The object detection framework could detect images of Comb jelly, Echinoderm, Sea Anemone and Ulke (Shorthorn sculpin) from the underwater images. The model attained a superior value of Mean Average Precision (mAP), precision, and recall of 99.5%, 99.2%, and 97.4%, respectively.

Predicted shifts in suitable habitat of interacting benthic species in a warmer and invaded Canadian Arctic

Climate change and related expanding shipping activity are predicted to increase the risk of aquatic invasive species arriving in the Arctic. The goal of this study was to predict the distribution of an interconnected set of native and non-native primary producers and primary and secondary consumers in this changing context. Groups of species were selected to represent a benthic coastal Arctic food web in Hudson Bay, including kelps and eelgrass as primary producers (Alaria esculenta, Agarum clathratum, Saccharina latissima, Laminaria solidungula, and Zostera marina), amphipods as primary consumers (Gammarus oceanicus and G. setosus), and fish as secondary consumers (sculpins Gymnacanthus tricuspis, Myoxocephalus scorpius, M. scorpioides, and M. quadricornis). Ensemble models were used to predict the distribution of these native and several analogue non-native species (species known to be invasive elsewhere that can be considered analogues to Hudson Bay species): Dumontia contorta, Undaria pinnatifida, Sargassum muticum, and Codium fragile (primary producers); Gammarus tigrinus (primary consumer); and Artediellus atlanticus and A. uncinatus (secondary consumers). Predicted habitat suitability of trophic groups and analogue non-native species were overlaid under current and future climate change scenarios to assess areas of change through time. The predicted direction of potential distribution shifts varies by species identity (species composition) but not trophic group. Overall trophic relationships and roles in the ecosystem are likely to be maintained over time because while some species are predicted to decrease their potential ranges (e.g., M. quadricornis), others in the same trophic groups are predicted to increase (e.g., M. scorpius). Overlap (or lack thereof) between native and analogue non-native species pairs are expected to vary through time enabling novel interactions (e.g., competition) in space and time. This approach will help to identify current and future high-risk areas for trophic level changes and interactions with invasive species in response to global warming.

Shallow subtidal marine benthic communities of Nachvak Fjord, Nunatsiavut, Labrador: A glimpse into species composition and drivers of their distribution.

Marine fjords along the northern Labrador coast of Arctic Canada are influenced by freshwater, nutrients, and sediment inputs from ice fields and rivers. These ecosystems, further shaped by both Atlantic and Arctic water masses, are important habitats for fishes, marine mammals, seabirds, and marine invertebrates and are vital to the Labrador Inuit who have long depended on these areas for sustenance. Despite their ecological and socio-cultural importance, these marine ecosystems remain largely understudied. Here we conducted the first quantitative underwater scuba surveys, down to 12 m, of the nearshore marine ecology of Nachvak Fjord, which is surrounded by Torngat Mountains National Park located in Nunatsiavut, the Indigenous lands claim region of northeastern Canada. Our goal was to provide the Nunatsiavut Government with a baseline of the composition and environmental influences on the subtidal community in this isolated region as they work towards the creation of an Indigenous-led National Marine Conservation Area that includes Nachvak Fjord. We identified four major benthic habitat types: (1) boulders (2) rocks with sediment, (3) sediment with rocks, and (4) unconsolidated sediments, including sand, gravel, and cobble. Biogenic cover (e.g., kelp, coralline algae, and sediment) explained much of the variability in megabenthic invertebrate community structure. The kelp species Alaria esculenta, Saccharina latissima, and Laminaria solidungula dominated the boulder habitat outside of the fjord covering 35%, 13%, and 11% of the sea floor, respectively. In contrast, the middle and inner portions of the fjord were devoid of kelp and dominated by encrusting coralline algae. More diverse megabenthic invertebrate assemblages were detected within the fjord compared to the periphery. Fish assemblages were depauperate overall with the shorthorn sculpin, Myoxocephalus scorpius, and the Greenland cod, Gadus ogac, dominating total fish biomass contributing 64% and 30%, respectively. Understanding the composition and environmental influences within this fjord ecosystem not only contributes towards the protection of this ecological and culturally important region but serves as a baseline in a rapidly changing climatic region.

Характеристика прибрежной ихтиофауны губ Восточного Мурмана в летний период 2020 года

In the article was considered species composition of fish in the littoral and sublittoral zones of Yarnyshnaya and Zelenetskaya bays (Barents Sea) during summer 2020. For the first time, the kelp snailfish Liparis tunicatus was recorded in the studied water area. At whole was discovered 15 species of fish and most abundent between them is staghorn sculpin Gymnocanthus tricuspis and shorthorn sculpin Myoxocephalus scorpius. Also quantitative characteristics of the distribution for each fish species are represented. The dynamics of abundance and diversity of coastal fish communities were analyzed. Comparing of perennial data with 2020 indicates that at the present observed relatively rich species composition, low fish distribution density, low abundance of young Gadidae, but high indicators of biodiversity in coastal communities.

Видовой состав рыб губы Белокаменная (Кольский залив) в мае и августе–октябре 2022 года

The species composition of the ichthyofauna of Belokamennaya Bay were carried out from May to October 2022 was studied. 10 species of fish belonging to 6 families were found in the study area. Most of the species belong to the boreal complex. The commercial status in the Barents Sea has seven (70 %) species of fish. The European flounder Platichthys flesus (Linnaeus, 1758) dominated in abundance (35 %) and the pollock Pollachius virens (Linnaeus, 1758) (33 %). In terms of biomass, a large share of the catch (43.6 %) was occupied by European flounder, and the European sculpin Myoxocephalus scorpius (Linnaeus, 1758) also accounted for a significant part – 22.2 %.

Bycatch in northeast Atlantic lobster and crab pot fisheries (Irish Sea, Celtic Sea and Bristol Channel)

Bycatch in valuable NE Atlantic baited ‘pot’ fisheries for lobster Homarus gammarus and edible crab Cancer pagurus has not been well documented, potentially limiting evidence-based management. Using onboard observers supplemented by fishers’ ecological knowledge (FEK) we characterised bycatch of fish and larger invertebrates in 10,741 pot hauls around the coast of Wales, UK, over 4 years in all seasons. A total of 1529 fish from 30 species, and around 15 species of invertebrate, were recorded. Bycatch abundance varied seasonally and spatially and was dominated by eight common and widespread taxa comprising six ‘core’ fish (two catsharks: bullhuss (Scyliorhinus stellaris) and smallspotted catshark (S. canicula); ballan wrasse Labrus bergylta, sea scorpions (Myoxocephalus scorpius &Taurulus bubalis combined), three-bearded rockling Gaidropsarus vulgaris, conger eel Conger conger, together 86% of fish abundance), velvet swimming crab Necora puber and spider crab Maja brachydactyla. Commercially important fish species were only caught in low numbers (3.0% of all fish), with cod Gadus morhua the most frequent (1.8% of all fish). Only two species of conservation interest were recorded: the large catshark Scyliorhinus stellaris which is locally abundant (assessed by the IUCN Red List of Threatened Species as ‘Near Threatened’ and ‘Vulnerable to extinction’ at European and global scales respectively), and a single legally retained spiny lobster Palinurus elephas. Retention or live release status was recorded for nearly all (96%) of the core fish individuals and varied widely with taxa: sea scorpions (never retained), Scyliorhinus stellaris (13% retained), smallspotted catshark, three-bearded rockling, conger eel (44–59% retained), with ballan wrasse having the highest retention (90% of 242 individuals; average of 5.5 individuals retained per trip when present). Observed high spider crab abundance combined with FEK of previous absence or scarcity suggest that this species has increased in northwards range and abundance in recent decades, possibly because of warming seas. No incidents of in-pot mammal or bird entrapment were recorded. The retention of fish for bait is not currently acknowledged in consumer advice or landings data. Possible effects of bait retention on populations of data-poor species which may be vulnerable to overexploitation (e.g., long-lived ballan wrasse) and coastal ecosystems are unknown and warrant further research.

The Effects of Phenanthrene on the Electrical Activity in the Heart of Shorthorn Sculpin (Myoxocephalus scorpio)

The Effects of Phenanthrene on the Electrical Activity in the Heart of Shorthorn Sculpin (Myoxocephalus scorpio)

Cumulative effects of long-term anthropogenic impacts on resident fish communities in subarctic fishing harbours

Ecosystems perceived to have sustained historical human pressure from multiple stressors are often considered to be degraded. Diversity and abundance of marine macroflora and macrofauna were observed at 17 harbour sites in Newfoundland (Canada) over four consecutive years (2008–2011), to determine cumulative effects of long-term anthropogenic impacts on coastal marine biota in small fishing harbours. A Principal Component Analysis was applied to evaluate the relative effects of physical harbour characteristics (harbour shape, size, and orientation), and those directly associated with anthropogenic influence (current and historical human population size, human landscape “footprint”, and operating capacity of the local fishing industry), on marine vegetation, fish, and invertebrate macrofauna. The first three principal components explained 77% of the cumulative variance of the physical harbour and anthropogenic variables. PC1 was dominated by variables associated with human use, and site depth; PC2 was associated with physical site orientation and the cumulative wharf length; and PC3 was associated with long-term use and harbour area. The densities of cod (Gadus spp.) and crab species increased significantly along the gradient of human impact metrics, while winter flounder (Pseudopleuronectes americanus), cunner (Tautogolaborus adspersus) and shorthorn sculpin (Myoxocephalus scorpius) decreased. Sessile fauna diversity and density, and flora percent cover correlated with long-term use and harbour area. Species densities changed in response to cumulative effects of long term human settlement near harbours, but prominent species were ubiquitous in these coastal ecosystems.

Food Choice and Prey Selection by Great Cormorants Phalacrocorax carbo in a Shallow Coastal Zone in the Dutch Delta Area: Importance of Local Flatfish Stocks

Coastal breeding Great Cormorants Phalacrocorax carbo foraging in a shallow part of the Dutch North Sea preyed upon abundant marine demersal fish species. In 2010–2012 intensive fish surveys were performed in the Voordelta area and in 2009–2015 Cormorant pellets were sampled in the breeding colony of Breede Water, Voorne, four times per year between March and September. In total 48 fish species were detected in the diet, 38 being marine species. Mainly flatfish were consumed, and European Plaice, Common Dab and Common Sole were the most important prey according to fish mass. Experimental trawling revealed 65 species of fish of which gobies, Herring, Whiting, Sprat, European Plaice and Common Dab were the most abundant. Compared to the trawl data, Cormorants showed a preference for Common Dab and Common Sole and for other solitary bottom fish like sandeels and Shorthorn Sculpin. These species were all common in the area. With respect to uncommon and rare species, no preferential selection was recorded. Densities of flatfish were highest in foraging areas closest to the breeding colony and possible depletion effects were only recorded in Common Dab. This diurnal species was already being preyed upon early in the season. Nocturnal foraging habits in other flatfish species, in combination with burrowing behaviour and rounded body shape are effective anti-predator traits and this was reflected in lower frequencies of these species in the Cormorants' diet. Consumption of freshwater fish by Cormorants at the beginning of the breeding period enabled an early start to breeding, and the increasing availability of flatfish in late spring matched the peak demand of rearing nestlings. The almost exclusive predation on flatfish was probably caused by the near-bottom foraging behaviour of most Cormorants and this habit made the birds feed on other abundant demersal fish species as well, such as Whiting, sandeels, Shorthorn Sculpin, Lesser Weever and dragonet species. And although numerous in the system, this bottom-oriented feeding behaviour of Cormorants therefore resulted in a very limited predation on pelagic fish species. In total we estimate an annual extraction by Cormorants of some 100 tonnes of fish being c. 77,600 kg flatfish and c. 20,700 kg other marine fish. Although with a foraging range partly outside the coastal zone, the extraction of fish by Harbour Seals Phoca vitulina and Grey Seals Halichoerus grypus outnumbered that of Cormorants by a factor of 9. As seals are known flatfish consumers, this suggests that there is competition between mammalian and avian predators on demersal fish stocks in the coastal zone.

Характеристика прибрежных сообществ рыб в губах Восточного Мурмана в летне-осенний период 2019 года

In the article was considered species composition of fish in the littoral and sublittoral zones of Yarnyshnaya and Zelenetskaya bays (Barents Sea) during summer and autumn 2019. At whole was discovered 15 species of fish and most abundent between them is young shorthorn sculpin Myoxocephalus scorpius. Also quantitative characteristics of the distribution for each fish species are represented. The dynamics of abundance and diversity of coastal fish communities were analyzed. Comparing of perennial data with 2019 indicates that at the present observed low abundance of young Gadidae, the presence of subdominant species, but high indicators of biodiversity in coastal communities.

Element concentrations, histology and serum biochemistry of arctic char (Salvelinus alpinus) and shorthorn sculpins (Myoxocephalus scorpius) in northwest Greenland

The increasing exploratory efforts in the Greenland mineral industry, and in particular, the proposed rare earth element (REE) mining projects, requires an urgent need to generate data on baseline REE concentrations and their potential environmental impacts. Herein, we have investigated REE concentrations in anadromous Arctic char (Salvelinus alpinus) and shorthorn sculpins (Myoxocephalus scorpius) from uncontaminated sites in Northwest Greenland, along with the relationships between the element concentrations in gills and liver, and gill histology and serum biochemical parameters. Concentrations of arsenic, silver, cadmium, cerium, chromium, copper, dysprosium, mercury, lanthanum, neodymium, lead, selenium, yttrium, and zinc in gills, liver and muscle are presented. No significant statistical correlations were observed between element concentrations in different organs and gill histology or serum biochemical parameters. However, we observed positive relationships between age and histopathology, emphasizing the importance of including age as a co-variable in histological studies of fish. Despite no element-induced effects were observed, this study is considered an important baseline study, which can be used as a reference for the assessment of impacts of potential future REE mine sites in Greenland.

Pleistophora typicalis . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Pleistophora typicalis , known only from Myoxocephalus scorpius , the shorthorn sculpin or bull-rout, M. quadricornis , the fourhorn sculpin, and Taurulus bubalis , the longspined bullhead, all 3 species of the fish family Cottidae (Scorpaeniformes). Some information on its morphology, dispersal and transmission and conservation status is given, along with details of its geographical distribution (Europe (France, Russia and UK)) and hosts ( Myoxocephalus scorpius, M. quadricornis and Taurulus bubalis ).

Splenic and renal melanomacrophage centers in shorthorn sculpins (Myoxocephalus scorpius) in Nuuk harbor, West Greenland

Splenic and renal melanomacrophage centers in shorthorn sculpins (Myoxocephalus scorpius) in Nuuk harbor, West Greenland

The Relationship between Myoglobin, Aerobic Capacity, Nitric Oxide Synthase Activity and Mitochondrial Function in Fish Hearts.

The dynamic interactions between nitric oxide (NO) and myoglobin (Mb) in the cardiovascular system have received considerable attention. The loss of Mb, the principal O2 carrier and a NO scavenger/producer, in the heart of some red-blooded fishes provides a unique opportunity for assessing this globin’s role in NO homeostasis and mitochondrial function. We measured Mb content, activities of enzymes of NO and aerobic metabolism [NO Synthase (NOS) and citrate synthase, respectively] and mitochondrial parameters [Complex-I and -I+II respiration, coupling efficiency, reactive oxygen species production/release rates and mitochondrial sensitivity to inhibition by NO (i.e., NO IC50)] in the heart of three species of red-blooded fish. The expression of Mb correlated positively with NOS activity and NO IC50, with low NOS activity and a reduced NO IC50 in the Mb-lacking lumpfish (Cyclopterus lumpus) as compared to the Mb-expressing Atlantic salmon (Salmo salar) and short-horned sculpin (Myoxocephalus scorpius). Collectively, our data show that NO levels are fine-tuned so that NO homeostasis and mitochondrial function are preserved; indicate that compensatory mechanisms are in place to tightly regulate [NO] and mitochondrial function in a species without Mb; and strongly suggest that the NO IC50 for oxidative phosphorylation is closely related to a fish’s hypoxia tolerance.

Histopathological effects of short-term aqueous exposure to environmentally relevant concentration of lead (Pb) in shorthorn sculpin (Myoxocephalus scorpius) under laboratory conditions.

Shorthorn sculpin (Myoxocephalus scorpius) has been used as a sentinel species for environmental monitoring, including heavy metal contamination from mining activities. Former lead-zinc (Pb-Zn) mines in Greenland resulted in elevated concentrations of metals, especially Pb, in marine biota. However, the potential accumulation of Pb and effects of the presence of Pb residues in fish on health of sculpins observed in the field have not been validated in laboratory experiments. Therefore, our aim was to validate field observation of shorthorn sculpin via controlled laboratory exposure to environmentally relevant concentrations of dissolved Pb. We evaluated the effects of a short-term (28 days) exposure to Pb on Pb residues in sculpin blood, gills, liver, and muscle and the morphology of gills and liver. The highest level of Pb was found in the gills, followed by muscle and then liver. Pb levels in liver, gills, and blood of Pb-exposed sculpins were significantly higher than those in control fish, showing that blood is suitable for assessing Pb accumulation and exposure in sculpins. Histopathological investigations showed that the severity score of liver necrosis and gill telangiectasia of Pb-exposed sculpins was significantly greater than in control fish. The number of mucous cells in gills was positively correlated with Pb concentrations in organs. Overall, the results validated field observation for the effects of Pb on wild sculpin and contributed to the improved use of the shorthorn sculpin as sentinel species for monitoring contamination from Pb mines in the Arctic.

Life cycle truncation in Digenea, a case study of Neophasis spp. (Acanthocolpidae).

Truncated life cycles may emerge in digeneans if the second intermediate host is eliminated, and the first intermediate host, the mollusc, takes up its role. To understand the causes of this type of life cycle truncation, we analyzed closely related species of the genus Neophasis (Acanthocolpidae) with three-host and two-host life cycles. The life cycle of Neophasis anarrhichae involves two hosts: wolffishes of the genus Anarhichas as the definitive host and the common whelk Buccinum undatum as the intermediate host. Neophasis oculata, a closely related species with a three-host life cycle, would be a suitable candidate for the comparison, but some previous data on its life cycle seem to be erroneous. In this study, we aimed to redescribe the life cycle of N. oculata and to verify the life cycle of N. anarrhichae using molecular and morphological methods. Putative life cycle stages of these two species from intermediate hosts were linked with adult worms from definitive hosts using ribosomal molecular data: 18S, ITS1, 5.8S-ITS2, 28S. These markers did not differ within the species and were only slightly different between them. Intra- and interspecific variability was also estimated using mitochondrial COI gene. In the constructed phylogeny Neophasis spp. formed a common clade with two other genera of the Acanthocolpidae, Tormopsolus and Pleorchis. We demonstrated that the first intermediate hosts of N. oculata were gastropods Neptunea despecta and B. undatum (Buccinoidea). Shorthorn sculpins Myoxocephalus scorpius were shown to act as the second intermediate and definitive hosts of N. oculata. The previous reconstruction of the two-host life cycle of N. anarrhichae was reaffirmed. We suggest that life cycle truncation in N. anarrhichae was initiated by an acquisition of continuous morphogenesis in the hermaphroditic generation and supported by a strong prey-predator relationship between A. lupus and B. undatum.

Energetic savings and cardiovascular dynamics of a marine euryhaline fish (Myoxocephalus scorpius) in reduced salinity

Few studies have addressed how reduced water salinity affects cardiovascular and metabolic function in marine euryhaline fishes, despite its relevance for predicting impacts of natural salinity variations and ongoing climate change on marine fish populations. Here, shorthorn sculpin (Myoxocephalus scorpius) were subjected to different durations of reduced water salinity from 33 to 15 ppt. Routine metabolic rate decreased after short-term acclimation (4–9 days) to 15 ppt, which corresponded with similar reductions in cardiac output. Likewise, standard metabolic rate decreased after acute transition (3 h) from 33 to 15 ppt, suggesting a reduced energetic cost of osmoregulation at 15 ppt. Interestingly, gut blood flow remained unchanged across salinities, which contrasts with previous findings in freshwater euryhaline teleosts (e.g., rainbow trout) exposed to different salinities. Although plasma osmolality, [Na+], [Cl−] and [Ca2+] decreased in 15 ppt, there were no signs of cellular osmotic stress as plasma [K+], [hemoglobin] and hematocrit remained unchanged. Taken together, our data suggest that shorthorn sculpin are relatively weak plasma osmoregulators that apply a strategy whereby epithelial ion transport mechanisms are partially maintained across salinities, while plasma composition is allowed to fluctuate within certain ranges. This may have energetic benefits in environments where salinity naturally fluctuates, and could provide shorthorn sculpin with competitive advantages if salinity fluctuations intensify with climate change in the future.

Trophic structure and resource utilization of the coastal fish community in the western Wadden Sea: evidence from stable isotope data analysis

We studied the trophic structure of the western Wadden Sea fish community through stable isotope analysis (δ13C and δ15N) of 1658 samples from 57 fish species collected between 2012 and 2016. Stable isotope values differed between species but did not vary between years or seasons, and only for some species with fish size. Stable isotope values were not different between immigrating (spring) and emigrating (autumn) fish, suggesting a similar trophic niche of the various fish species in the coastal zone and inside the Wadden Sea. For the majority of species, average δ13C values were within the range of -12 to -20.5‰, showing that both (marine) pelagic and benthic primary producers were at the base of the food web. Average δ15N values varied among species from 13-18‰, resulting in estimated trophic positions (TPs) of 2.1-5.5 with the majority between 2.2 and 3.5. Thick-lipped grey mullet Chelon labrosus, golden grey mullet C. aurata, greater pipefish Syngnathus acus and pilchard Sardina pilchardus had the lowest TP (2.2-2.4). Among the common species (>10 observations), the highest TP values (3.4-3.5) were found for twaite shad Alosa fallax, smelt Osmerus eperlanus, bull-rout Myoxocephalus scorpius, bass Dicentrarchus labrax and cod Gadus morhua. For all species, estimated TPs based on isotope values were lower than those based on stomach content composition (2.0-4.7), which could be explained by species-specific differences in trophic fractionation or by underestimation of the contribution of smaller prey species in the stomach content analysis. The trophic niche space of benthopelagic species was the smallest and overlapped with that of the pelagic and benthic species. In terms of area use, trophic niche space was smaller for juvenile marine migrant species (nursery-type species) and overlapped with that of the (near-)resident species and marine seasonal visitors. Potentially, trophic competition is highest for the functional group of benthopelagic species and the guild of juvenile marine migrant species (nursery-type species).

Gut microbiome of the White Sea fish revealed by 16S rRNA metabarcoding

To date, it has been increasingly clear, that microbiota plays essential role in the host microorganism. Due to high phylogenetic diversity and wide distribution understanding of gut microbiota of fish is ambiguous. We elucidate previously undescribed diversity of bacteria in the White Sea fish posterior intestine based on 16S rRNA metabarcoding: shorthorn sculpin (Myoxocephalus scorpius), lumpfish (Cyclopterus lumpus) arctic flounder (Liopsetta glacialis), cod (Gadus morhua), and herring (Clupea pallasii). Proteobacteria were most abundant in all the samples. All datasets contained high number of reads corresponded to Psychrobacter, Halomonas, Pseudoalteromonas and Vibrio abundant in the White Sea water.Vast majority of bacterial reads corresponded to the Vibrionaceae (Aliivibrio, Vibrio, and Photobacterium). It is in accordance with our previous study focused on bioluminescent bacteria, where we isolated strains of these genera from the same fish intestine samples. The datasets of G. morhua and Cl. pallasii were enriched by reads of Shewanella (also isolated previously microbiologically due to luminescence of some its strains); the datasets of G. morhua and M. scorpius contained high number of Mycoplasma, which is in line with previous reports on the microbiome of marine fish gut from other geographical regions. Collectively, on the one hand, the study is a confirmation of known data on marine fish gut microbiome, on the other hand, it reveals some specific patterns of White Sea fish gut microbiota, e.g. presence of bacteria common for water from this region.