Search Results (22)

The morphological peculiarities of receptor neurons and support cells in the olfactory epithelium of male yellowfin sculpin (Cottocomephorus grewingkii; Dybowski, 1874) were studied during the pre-spawning, spawning (when males do not feed and have a higher sensitivity to female pheromones), and guarding (the fertilized eggs) periods. This study was performed using electron transmission and laser confocal microscopy. Structural changes in the fish olfactory epithelium are associated with the shift in olfactory signals from alimentary to pheromonal. These results expand our knowledge of the odorant-dependent plasticity of the periphery of the fish olfactory system. Full article

The Alaskan (highbrow) sculpin, Triglops metopias, is a rare and poorly known species with a restricted distribution in the North Pacific. This species has been previously recorded only from off the Aleutian Islands and the Gulf of Alaska, while previous records from the western North Pacific have been controversial. The presence of T. metopias in the northwestern Pacific off the Kuril Islands is confirmed in the current study. Forty-one specimens were included in morphological and molecular analyses, including principal component analysis and DNA barcoding. The detailed morphological description of the Kuril Islands specimens is given. Molecular analysis inferred from the mitochondrial cytochrome b sequences showed no separation of this species from T. pingelii, although they can be distinguished by external morphology, including the use of the multivariate statistical approach. The geographical distribution of T. metopias in the North Pacific is discussed. This species is considered to be a recently diverged species with a disjunct distribution from the Kuril and the Aleutian Islands eastwards to the Gulf of Alaska. Despite its morphological similarity to T. pingelii, both species can be distinguished by a combination of meristic and morphometric characters, in particular, the wider interorbital space (10.4–22.4, mean 14.8 vs. 6.9–11.4, mean 9.2), shorter pectoral fins (18.7–24.9, mean 21.0 vs. 21.7–27.4, mean 24.1), and the on average more numerous oblique dermal folds (92 vs. 54). Full article

The shorthorn sculpin (Myoxocephalus scorpius) is considered a suitable sentinel species for marine pollution in the Arctic due to its ecology and stationary habits. To evaluate its role as a bioindicator for potential natural and anthropic impacts on the marine ecosystem of the Kongsfjorden (Svalbard, Norwegian Arctic), 33 female and male specimens of shorthorn sculpins were collected in July 2018 in proximity of the Ny-Ålesund international research facility and analyzed for the content of 25 major and trace elements and methylmercury (MeHg) in the muscle, liver, gonads, and gills by using spectroscopic techniques. Most elements had their maximum average concentrations in the gills (Al, Cr, Fe, Mn, Na, Ni, Pb, Se, Si, Sr, and V), while the livers featured higher contents of some toxic and heavy metals (As, Cd, Cu, Mo, and Zn). The muscle was characterized by high contents of Ca, K, and Mg, while Ba, Co, and P were mostly concentrated in the gonads. The gonads presented higher concentrations of Cr, K, Mg, Ni, P, and V for the males and Co, Cu, Fe, Mn, and Se for the females. Both the total Hg and MeHg concentrations in the muscle correlated with the fish size, indicating bioaccumulation, although high Se/Hg molar ratios (11.0 ± 2.2) suggested a low toxic potential of mercury. Full article

The geographic ranges of slimy (Uranidea cognata) and mottled (Uranidea bairdii) sculpin overlap broadly across cool and coldwater streams and rivers in North America, where they can serve very important roles in fish community dynamics. The diet diversities of slimy and mottled sculpin were examined in early March (late winter) during eight out of nine years after the August 2007 catastrophic flooding in four streams to assess potential diet shifts as benthic invertebrate prey communities recovered post-flood. In total, 10,823 prey items, representing 39 invertebrate taxa and three fish taxa were identified from the stomachs of 532 slimy sculpins (present in Garvin Brook, Gilmore Creek, and Trout Run) and 179 mottled sculpins (present in Middle Fork Whitewater River). Only four prey taxa were consumed by sculpin in all streams: midge larvae and pupae (Diptera: Chironomidae), blackfly larvae and pupae (Diptera: Simuliidae), Hydropsyche caddisfly larvae (Trichoptera: Hydropsychidae), and Baetis mayfly nymphs (Ephemeroptera: Baetidae). Midges dominated diets of both slimy (61% of prey by number) and mottled (76%) sculpin across all years. Consequently, Shannon diversities of diets were typically low across all years and streams for slimy sculpin (annual site range 0.07–0.83) and across years for mottled sculpin (annual range 0.11–0.46). Diversities and taxa richness of slimy sculpin diets increased in Garvin Brook and Trout Run across the study years (driven by significant declines in midge dominance) but remained relatively unchanged for slimy sculpin in Gilmore Creek and mottled sculpin in the Middle Fork. Individual slimy and mottled sculpin differed significantly both in the numbers of taxa consumed per fish (<2 versus 2.5 taxa/fish, respectively) and in the numbers of individual prey per fish (11 versus 26 prey, respectively). Slimy sculpin in two streams displayed modest shifts in diets as benthic prey communities recovered during the 9-year period post-flood, whereas slimy and mottled sculpin in other streams displayed little to no changes in diets. Differing flood severity among streams may have produced the different responses observed in sculpin diets. Full article

Slimy sculpin (Uranidea cognata) inhabit coldwater streams in southeastern Minnesota, USA, many of which were subjected to probable 2000-year flood events in August 2007. Floods scoured streambeds, created new stream channels, and greatly reduced benthic invertebrate communities that serve as the primary food resource for sculpin. Diets and Fulton condition of sculpin in Gilmore Creek (with moderate flooding) and Garvin Brook (with very severe flooding) had been examined just prior to flooding and were re-examined 2 weeks after flooding to assess possible diet and condition changes. Diets, body condition, and reproductive fitness of sculpin were examined 7 months post-flood in these same two streams, plus nearby Trout Run (which also experienced very severe flooding). Sculpin condition declined slightly post-flood in Garvin Brook but improved in Gilmore Creek. Prior to spring spawning, the condition of Garvin Brook sculpin had improved, but Gilmore Creek fish condition had worsened. Sculpin diets were more diverse before and after flooding in Gilmore Creek than in Garvin Brook, although the diets of fish from both streams were dominated (>55%) by midge (Diptera: Chironomidae) larvae. Diets remained largely unchanged before versus after flooding in the more severely flooded Garvin Brook, but they changed in Gilmore Creek, becoming more midge-dominated. Prey number per sculpin stomach declined post-flood in Gilmore Creek but not in Garvin Brook, although the dry mass of prey/fish wet mass declined post-flood in both streams. Pre-spawn sculpin displayed no patterns in reproductive fitness (gonadosomatic index, hepatosomatic index, oocyte number) among the three streams that may have been related to flooding severity the previous summer. Sculpin diets and condition were not altered as expected by flooding, and food resource recovery apparently was rapid enough to prevent longer-term impacts on sculpin condition and reproductive fitness in the streams examined. Full article

The diverse freshwater fish fauna of the Japanese archipelago is distributed among four main island landmasses, which include Hokkaido in the north, with many diadromous species. One relatively well-preserved river drainage along the southern coast of Central Hokkaido is the Mukawa River. Fish fauna surveys in the Mukawa River were mostly in downstream areas and the fish diversity is not well-documented among the upper, lower river, and coastal environments. Fish communities in the river, estuary, and sea were sampled using eDNA analysis to evaluate upstream and downstream species detections, and tidal and spatial detection variation near the river mouth. The number of species was higher at the river mouth and nearshore sites compared to the river and offshore. Fish detections reflected life history categories (freshwater resident, diadromous, brackish, or marine) and the environments. Similarity analysis showed that fish species compositions were divided into (1) upstream and midstream, (2) downstream and river mouth, (3) adjacent shore, and (4) offshore. Salmonid, cyprinid, loach, and sculpin species were detected in the river, compared to a mixture of species downstream and along the coast. This rapid assessment type study demonstrated that eDNA survey methodology would be effective for multiple river comparative surveys, seasonality studies, or evaluating possible effects of cross-river weirs or dams. Full article

Toxic runoff from heavy rains on 26 September 2019 caused a complete fish kill on the 2 km long headwater reach of Garvin Brook, Winona County, Minnesota, USA. This project examined the recovery of the slimy sculpin (Uranidea cognata) population within the lower 900 m of the kill zone, comparing relative abundance estimates and size structures between the kill zone and a downstream, unimpacted reference section. Electrofishing surveys were conducted at 24 sites (12 within both kill and reference zones) at 6, 11, 18, 28, and 42 months post-kill to assess relative abundance (catch-per-effort (CPE), fish/min) and population age structures (based on total length). At six months post-kill, sculpin were present throughout the kill zone. However, adult CPE declined significantly with upstream distance, which was suggestive of the ongoing immigration of adult sculpin from downstream. Age structures were similar in kill and reference zones with all size/age groups present in both zones after six months, while CPE was twice as high in the reference (6.3 fish/min) versus the kill zone (3.0 fish/min). After 11 months, CPE did not differ between zones (14 fish/min) and remained that way for the remainder of the study. However, age structures differed dramatically between zones at both 11 and 18 months post-kill; adult sculpin were significantly more abundant in the reference zone, whereas juvenile fish dominated the kill zone. By 28 months post-kill, both sculpin abundance and age structure within the kill zone had fully recovered from the kill. Sculpin recovery was accomplished mostly through enhanced reproduction within the kill zone following initial post-kill movements of both adult and juvenile fish into the kill zone from downstream. Low predation on juvenile sculpin due to a reduced abundance of trout and adult sculpin post-kill likely allowed more rapid recovery of the sculpin population within the kill zone. Full article

The roughskin sculpin (Trachidermus fasciatus) is an endangered fish species in China. In recent years, artificial breeding technology has made significant progress, and the population of roughskin sculpin has recovered in the natural environment through enhancement programs and the release of juveniles. However, the effects of released roughskin sculpin on the genetic structure and diversity of wild populations remain unclear. Studies on genetic diversity analysis based on different types and numbers of molecular markers have yielded inconsistent results. In this study, we obtained 2,610,157 high-quality SNPs and 494,698 InDels through whole-genome resequencing of two farmed populations and one wild population. Both farmed populations showed consistent levels of genomic polymorphism and a slight increase in linkage compared with wild populations. The population structure of the two farmed populations was distinct from that of the wild population, but the degree of genetic differentiation was low (overall average Fst = 0.015). Selective sweep analysis showed that 523,529 genes were selected in the two farmed populations, and KEGG enrichment analysis showed that the selected genes were related to amino acid metabolism, which might be caused by artificial feeding. The findings of this study provide valuable additions to the existing genomic resources to help conserve roughskin sculpin populations. Full article

Alcichthys elongatus is the only species in the genus, and this work is the first to provide a comprehensive mitogenome analysis of this species. The A. elongatus mitogenome was 16,712 bp long, with biased A + T content (52.33%), and featured thirteen protein-coding genes (PCGs), twenty-two tRNAs, two rRNAs, and the control region (D-loop). The H strand encoded twenty-eight genes (twelve PCGs, fourteen tRNA, and two rRNA) and the control region, whereas the L strand encoded the remaining nine genes (ND6 and eight tRNA). Except for COXI, which started with GTG, all PCG sequences started with ATG and ended with TAA (ND4L, ND5, COXI, ATP8) or TAG (ND1, ND6) termination codons, with some (ND2, ND3, ND4, COXII, COXIII, ATP6, Cytb) having an incomplete termination codon. Except for tRNA-serine-1 (trnS), the majority of the tRNAs exhibited characteristic cloverleaf secondary structures. Based on 13 PCGs, phylogenetic analysis placed A. elongatus in the same clade as Icelus spatula. This genomic data will be useful for species identification, phylogenetic analysis, and population genetics. Full article

The most recent assessment (2008) of the IUCN Red List of Threatened Species classified Romanichthys valsanicola as critically endangered (CR). In December 2022, an expert team from the National Institute for Research and Development in Environmental Protection Bucharest investigated the presence of the species in historical locations and in other potential sites. The authors correlated public data to the actual habitat area to calculate the potential species density in relation to the specific territorial behavior. The ecological carrying capacity was represented by the consensus between the behavioral density limitations and the trophic limitations of the actual species potential habitat. Both trophic availability and populational density present encouragingly high values for the sculpin perch in the Valsan River, indicating that the natural habitat could host a considerably higher number of individuals. Full article

The Shoshone sculpin Cottus greenei is a micro-endemic species and an extreme habitat specialist, geographically restricted to the spring outlets that flow from the Snake River Plain Aquifer into the Snake River within the Hagerman Valley of south central Idaho. Although previous studies documented the range of the species and its relative abundance, no studies have assessed genetic diversity and structure. We sampled 20 populations from throughout the species range and genotyped 1311 with a panel of 12 microsatellite loci. Results indicate very high levels of genetic differentiation among most populations (average pairwise F_ST = 0.24), indicating limited gene flow. Preservation of the genetic diversity of this species will require the protection and preservation of multiple isolated populations. Full article

According to the modern fish system, one species of fourhorn sculpin Triglopsis quadricornis lives in the Baltic Sea and Arctic waters. In the present study, sculpins from the Baltic and White Seas were studied using different methods: morphological analysis to establish patterns of the seismosensory system, tomography for the study of cranial bones, X-ray imaging for the study of the axial skeleton, as well as phylogenetic analysis of two mtDNA markers (control region and CO1) and one nDNA marker (RAG1). The results obtained by these methods were used to prove the existence of two species: T. quadricornis in the Baltic Sea and Triglopsis sp. in the White Sea. These species differ significantly in the unique shape and size of the bony outgrowths on the head, as well as in the number of bony plates on the body. Genetic differences between the species were expressed in the formation of T. quadricornis and Triglopsis sp. independent clusters on Bayesian phylogenetic trees reconstructed based on the sequences of the mtDNA control region and RAG1. Full article

The features of the spatial and vertical distributions, and size–age and size–sex structures of the ribbed sculpin Triglops pingelii of the Kara Sea are presented. In September 2019, this species was recorded at depths from 18 to 235 m at a bottom temperature from −1.5 to +1.6 °C. The densest concentrations were recorded northeastward of the Yamal Peninsula, at the outlet of the Gulf of Ob at a depth of 18–21 m and a bottom temperature from −1.5 to −1.0 °C. Individuals with a length of 46–126 mm and a body weight of 0.35–15.60 g aged 1+ to 4+ years were recorded in trawl catches. However, fish with a length of 51–90 mm and a body weight < 6 g aged 1+–2+ years dominated. Among fish > 71 mm long, the proportion of females increased sharply, reaching 100% with a length of 120 mm. The individual fecundity of female ribbed sculpins in the Kara Sea with a length of 89–123 mm varied from 100 to 316 (on average 215 ± 15) eggs. It is shown that this species is a necto-bentho-ichthyophage whose main prey are benthic and bentho-pelagic crustaceans (mainly amphipods and mysids), as well as juveniles of various fish, the total proportion of which is >99% of the food weight. In this sculpin, age-related changes in the diet composition are well expressed, i.e., as the size increases, the relative importance of the former prey group decreases sharply, and that of the latter two groups, on the contrary, increases. A comparative analysis of data on the biology and distribution of the six most abundant or common Triglops spp. makes it possible to attribute the ribbed sculpin to medium-sized representatives of the genus, whose maximum length is similar to those of T. jordani from the North Pacific, as well as T. murrayi and T. nibelyni from the Arctic. The lifespan of the ribbed sculpin is within the same limits as reported for other Triglops spp. Its individual fecundity in the Arctic seas is comparable to that of other Triglops species living here, but is significantly lower than that of individuals of this species and other congeners from the northwest Pacific Ocean. Full article

This work simulates the consequences of HIREC using stone sculpins as model organisms. Sex-dependent effects of long-term noise exposure at mean sound pressure levels of 160–179 dB re 1 μPa (SPL_pk–pk) were measured. We applied a multilevel approach to testing the stress response: a comparative analysis of the macula sacculi and an assessment of hematological and molecular stress responses. Noise exposure resulted in hair cell loss, changes in some cytometric parameters in blood, and an increase in the number of functionally active mitochondria in the red blood cells of males and its decrease in females, demonstrating a mitochondrial allostatic load and depletion of functional reserve. Finally, a statistically significant decrease in the telomerase activity of the auditory epithelium and a shortening of telomere length in the brain as molecular markers of stress were observed after noise exposure only in females. No significant decrease in telomerase activity and shortening of telomere length in nerve target tissues were observed in stressed males. However, we recorded an increase in the telomerase activity in male gonads. This sex-dependent difference in load may be associated with accelerated cellular aging in females and lower stress-related long-term risk in males. In this article, we discuss possible reasons for these noise-induced stress effects. Full article

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. Full article