Native Fish Research Articles

Stable isotope analysis of western Lake Superior predatory fishes, part one: Trophic niche overlap

Characterizing food web interactions between introduced and native fish predators is important to quantify niche overlap, assess predator–prey balance, and support fisheries management. Lake Superior provides an ideal setting to investigate potential trophic overlap between native top predators, lake trout (Salvelinus namaycush) and walleye (Sander vitreus), and a diverse assemblage of introduced salmonids. Angler-caught fish were used to measure trophic position and niche overlap between predatory fishes in the western arm of Lake Superior based on carbon and nitrogen stable isotope ratios (δ13C, δ15N). Within a species, we did not find consistent differences in either δ13C or δ15N values by sex, collection year, capture location, or length. Among species, the range in δ15N values was >5 ‰, indicating that these species occupy ∼2 trophic positions, with dietary reliance ranging from primarily invertebrates to primarily fish, whereas the range in δ13C values indicated dietary reliance on a mix of pelagic and benthic prey. Combined, the δ13C and δ15N values revealed siscowet lake trout as the apex predator having a distinct trophic niche, while walleye and lean lake trout were intermediate trophic position predators with overlapping isotopic niches, and introduced salmonids were the lowest trophic position predators with overlapping trophic niches. Overlapping trophic niches indicated similar resource reliance and habitat occupancy among native lake trout and walleye, as well as among introduced salmonids, but less so between native and introduced predators.

Passage efficiency through fishways of species of the family Cyprinidae and their management implications for fragmented rivers

The contemporary management of fragmented river systems is in a trade-off between the societal benefits of instream barriers (e.g. hydropower, flood risk management) and the ecological harms of their adverse impacts on fish populations. The consequent fragmentation can be mitigated through fishway construction, with mitigation performance measured using species-specific passage rates and efficiencies. There is, however, a bias in passage efficiency studies towards diadromous fishes and, although fish of the Cyprinidae family play a significant role in the fish assemblages of rivers worldwide, their passage efficiencies are poorly understood. Here, systematic review and meta-analyses assessed the passage efficiencies of cyprinid fishes through fishways that have been measured using telemetry methods. Passive integrated transponder (PIT) telemetry was the most common evaluation method of passage efficiency due to their high read rates and relatively low costs versus alternative telemetry methods. These methods revealed cyprinid passage efficiencies were highest through vertical slot fishways and lowest through nature-like constructions, with overall passage rates comparing favourably to anadromous salmonid fishes. Fish were most active during spring and summer, with passage and associated movements often related to spawning. Passage rates of non-native fishes were also higher than for native fishes. Despite the growing acknowledgment of how fishways influence potamodromous fish dispersal and distribution in rivers, passage data remain scarce, preventing managers and policy-makers from making informed decisions on optimal passage solutions for multiple fish species in highly fragmented rivers.

Freshwater habitat invaders: Impacts on artificial flow refuge use by native fish under pulsed flows

Flow regulation and the spread of invasive species are significant threats to freshwater biodiversity, including native fish communities in rivers across the globe. The bleak (Alburnus alburnus), an invasive fish currently widespread throughout the main rivers of the Iberian Peninsula, threatens native fish biodiversity, mostly via trophic competition and hybridisation. In this study, we assessed the impacts of bleak presence and rapid flow fluctuations (both main and interactive effects) on the use of artificial habitats (a flow refuge) and the stress physiology of barbels. We examined how bleak's presence influenced the selection of flow refuges by the native Iberian barbel (Luciobarbus bocagei) under base (continuous 7 L s−1 flow stimulus) and pulsed (7 L s−1 to a 60 L s−1 pulse) flows in an indoor flume. We quantified habitat use within three specific regions of two installed flow refuges and two physiological responses (glucose and lactate) associated with the stress axis. The results indicated that the presence of bleak significantly reduced flow refuge use by barbels and this effect was more prominent during pulsed flows. Additionally, barbels exhibited higher levels of glucose and lactate in the presence of bleaks. These results show that bleaks compete with barbels for habitat under fluctuating flows and induce physiological adjustments that may reduce the ability of barbels to find low-velocity areas to shelter. Overall, the bleaks had a competitive advantage under high flow variability. This underscores the need for further studies and effective management strategies to protect native freshwater fish communities in the context of biological invasions and anthropogenic flow variability.

Numerical simulation on the interaction of median fins for enhancing vortex dynamics and propulsion performance in fish self-propelled swimming

Studies have shown that fish can enhance propulsion performance by utilizing the interaction between median fins (dorsal, anal, and caudal fins), compared to fish with only caudal fin. However, most of the current studies are based on the fish oscillating in-place, and the analysis of median fins interaction to improve swimming propulsion performance is still insufficient, and the mechanism needs further study. This study applied three-dimensional numerical simulation methods to solve the process of grass carp accelerating from a stationary state to cruising state under different body and median fins combination, as well as different motion parameter models. A comparative quantitative analysis of different models was conducted to assess the impact of median fins interactions on enhancing swimming performance, with a detailed analysis of the hydrodynamic mechanisms and their relationship with vortex dynamics. The results indicated that interactions between median fins could generate significant hydrodynamic benefits, with the fish's average swimming speed increasing up to 4.6 times, thrust up to 33.47%, and swimming efficiency up to 25.48%. This study found that the enhancement of propulsion performance was due to the formation of high-intensity and persistent posterior body vortices by the movements of the dorsal and anal fins, which were captured by the leading-edge of the caudal fin, greatly enhancing the strength of the leading-edge vortex. This study elucidates the hydrodynamic mechanisms of the interaction between median fins and could provide new insights into the efficient swimming mechanism of fish in nature.

Consumer perspectives towards aquaponics: Products and native fish cultivation

Abstract Aquaponics is a farming system that integrates hydroponics and aquaculture. Many questions and concerns about the feasibility of aquaponics to sustain food productivity and its potential market remain unknown. One of them is the consumer’s perception and willingness to pay for aquaponic products. This study presents findings and analysis regarding consumer perception, knowledge and acceptance of aquaponic products in Malaysia, particularly native fish species cultivated within aquaponic system. A total of 385 respondents participated in this study from all regions (northern region, central region, east coast, southern region, Sabah, and Sarawak) in Malaysia. Overall, a significant proportion of consumers (84%) had not practised aquaponics, and 63% had not made purchases of any aquaponic products before. Consumers’ decisions to purchase aquaponic products is primarily influenced by price (79.2%) and food safety (67.8%). Other significant factors include food nutrition (52.7%), cultivation methods used in production (39.7%), taste and texture of aquaponic products (33%), accessibility to these products (0.5%) and concerns related to zoonotic diseases in aquaponic products (0.3%). Overall, consumers had a positive outlook on the benefits of aquaponics and its products. However, they had a neutral attitude towards purchasing and were willing to spend more on aquaponic products compared to products produced using conventional farming. Consumers also had a positive attitude towards culturing native fish species in aquaponics systems and had a neutral attitude when asked to buy native fish species cultivated in aquaponics systems. The study’s findings show a potential market for aquaponic products in Malaysia. However, more efforts are needed to increase awareness and promote aquaponics systems in Malaysia.

Phenotypic and Transcriptomic Analysis Revealed a Lack of Risk Perception by Native Tadpoles Toward Novel Non-Native Fish.

The introduction of alien species poses a serious threat to native biodiversity, and mountain lake systems in the southwest of China are particularly vulnerable to the introduction of non-native fish. The prey naivety hypothesis states that native species may not be able to recognize novel introduced species due to a lack of common evolutionary background and therefore become easy targets, so the impacts of non-native fish on mountain endemic amphibians need to be urgently assessed. In an ex-situ experiment, we exposed the tadpoles of the Chaochiao Brown Frog (Rana chaochiaoensis), endemic to western China, to kairomones of both native and translocated fish species, and their phenotypic and genetic response patterns were compared. The results revealed significant phenotypic plasticity responses in total length (TOL), tail length (TL), and tail muscle width (TW) of tadpoles induced by native fish kairomone, while tadpoles exposed to translocated fish kairomone exhibited weaker phenotypic changes. At the transcriptional level, the number of differently expressed genes (DEGs) in the native fish treatment was 3.1-fold (liver) and 52.6-fold (tail muscle) higher than in the translocated fish treatment, respectively. There were more unique DEGs in the native fish treatment, primarily enriched in terms and pathways related to stress response, energy metabolism, and muscle development. The study revealed a lack of risk perception by native tadpoles toward novel non-native fish, providing new evidence for the prey naivety hypothesis from both phenotypic and molecular perspectives. Future conservation efforts should prioritize assessing the impacts of non-native fish on alpine and subalpine threatened and narrowly distributed amphibians. Additionally, prevention, early warning, monitoring, and removal of non-native fish should be carried out as soon as possible.

Farm dams: A valuable interim step in small‐bodied threatened fish conservation

AbstractFreshwater fish are facing an extinction crisis on a global scale, with increasing demand for human water consumption driving the regulation and degradation of freshwater ecosystems. Flow regulation especially poses a threat to small‐bodied floodplain and creek specialist species through increasing population fragmentation and isolation, loss and degradation of habitats, and interactions with predators and competitors, resulting in reductions in species' range and abundance. Conserving and recovering many small‐bodied fish species will likely require translocation from wild habitats to refuge habitats to reduce extinction risk and provide buffers against catastrophic natural events (e.g., drought, bushfires). We assessed the value of semi‐artificial farm dams, an abundant feature in the Australian landscape, as interim refugia for the threatened southern pygmy perch Nannoperca australis (Percicthyidae). We compared the relative abundance, population size–structure and body condition of fish introduced (3–4 years prior) into three farm dams with those of three nearby creeks to assess the feasibility of farm dams as a resource to assist small‐bodied native fish conservation and recovery. Farm dams had higher abundance of fish, and equivalent size structure and body condition compared with creek populations, highlighting that suitable farm dams are a valuable and underutilized asset for threatened species' conservation globally.

CHARACTERIZATION OF PHYSICO-CHEMICAL AND BIOLOGICAL PARAMETERS IN AREAS WITH FISHING POTENTIAL

In the present study, the physico-chemical quality of the water in the Midia coastal area, the Tasaul Lake and the Siutghiol Lake water bodies were analyzed, as integrated sites in the territory of the North Dobrogea FLAG. This study allows establishing the state of favourability of the aquatic ecosystem, focusing on the chlorophyll content as the basis of the trophic level. The premise of a stable ecosystem induces the possibility of developing natural fish resources. An essential attribute in the context of preserving natural heritage and increasing the attractiveness for fishing activities, is the need to evaluate the qualitative and quantitative profile of the phytoplankton and, respectively, the eutrophication indicators. If aquaculture activities will be developed in the analyzed areas in the future, they could increase the economic value of the Romanian sector of the Black Sea. The biological analyzes of the water quality are the basis of the substantiation of some methods of its determination and evaluation. Thus, testing the concentration of chlorophyll, the classes of algae and the photosynthetic activity, are useful for the evaluation of eutrophication in the aquatic environment, but also for the evaluation of productivity in the surface waters studied. At the same time, the determination and evaluation of the physical and chemical parameters of water quality allowed the realization of some correlations with the structure of the biota. In this sense, the analysis methods are based on the use of modern equipment based on real time (in situ) determinations.

Fish Species Assemblages and Diversity in Water Body Infested by Alien Species

Human is one of the mediators for non-native species invasion, especially in the aquatic ecosystem. Aquaculture and sport fishing activities are the main reasons for non-native fish introduction, especially in man-made habitats. In the present study, we determined the fish community between the invaded as opposed to pristine ecosystems in north Terengganu, Malaysia. The primary data was collected using hook and line, hand-held push net, cast net and gills net while secondary data were also utilised from published and unpublished data. The fish general information including functional traits and prey-predator relationship were obtained from literature and reliable online resources. The data were used to construct hypothetical diagrams and analyzed using taxonomic distinctness index. The fish community between the two habitats differ significantly in which the non-native fish invaded habitat has much lesser fish species richness than that of the pristine habitat. Taxonomic diversity between the two habitats also was markedly different. The non-native Cichla ocellaris added predation pressure to fish community in the lacustrine habitat as the apex predator and were proven to feed on the native fish fauna in the lake. We discuss the community structure in both habitats and explore the further impact of invasion by this invasive alien species on the native fish species. We conclude that the presence of Cichla ocellaris amplify pressure to native fish community in the man-made lake.

Economic assessment and sustainable management of artisanal fisheries: Insights from River Jhelum, Kashmir, India

This study was conducted to comprehensively assess artisanal fishers’ economic and financial viability, relying heavily on a shared resource, namely the River Jhelum. Employing a proportional multi-stage stratified sampling approach, a total of 200 fishers were interviewed across six districts in Kashmir, covering the entire length of the river. The Benefit Cost Ratio (BCR) of 1.1, coupled with a positive Net Present Value (NPV), underscores the economic profitability of artisanal fisheries. Constraint analysis highlighted that fishermen express substantial concerns regarding the ongoing decline in both catch and the composition (Garret score: 83) of native fish species, particularly Schizothorax, and pollution in the river (Garret score: 73). Considering the perspectives of all stakeholders, it becomes evident that comprehensive sustainability measures are imperative. To achieve this, multiple stakeholders must collaborate and establish a unified administrative body, solely dedicated to the protection of riverine resources. In addition to implementing a two-month fishing ban and modifying the licensing policy, maintaining a detailed record of daily fish catches, including both biological and economic data, at each fishing site is also crucial. Such actions will facilitate the implementation of optimal exploitation levels for this invaluable inland water resource. Keywords: Constraint analysis, Economic performance, Financial feasibility, Net present value, Schizothorax, Sustainability

Assessment of plankton diversity and physico-chemical characteristics for sustainable fish production in a tropical reservoir in South India

Plankton forms an important component of the aquatic ecosystem and act as indicators of fish diversity, pollution levels and environmental disturbances. They form an important natural fish food resource and play a vital role in the trophic structure of the ecosystem. In the present study a systematic assessment of the community distribution and diversity of plankton was conducted in the Karapuzha Reservoir in South India. Thirty six genera of phytoplankton belonging to 4 classes viz, Chlorophyceae, Bacillariophyceae, Dinophyceae and Myxophyceae were identified. Eleven genera of zooplankton belonging to four classes; Protozoa, Rotifera, Cladocera and Copepoda were also recorded. The Jaccard index of similarity showed that pre-monsoon and monsoon seasons shared a similar plankton composition. Diversity indices revealed the highest values during monsoon, while the Dominance index indicated the highest species dominance during post-monsoon (0.199) followed by pre-monsoon (0.1445) and monsoon (0.1417). Water quality parameters were found to have a significant correlation with plankton abundance in the reservoir. ShannonWeiner index indicated that the Karapuzha Reservoir ecosystem is moderately polluted. Seasonal variations in plankton composition showed the highest species abundance during the pre-monsoon followed by post-monsoon and monsoon seasons. Keywords: Diversity index, Plankton abundance, Planktivorous fish, Reservoir ecosystem, Seasonal variation

Trophic niche of a nonnative invader and environmental drivers of its increasing populations in the coastal Everglades

AbstractThe Florida Everglades is a critically important, but highly threatened ecosystem that is becoming increasingly susceptible to the invasion of non-native species. This study investigated the ecological role of the invasive peacock eel (Macrognathus siamensis) within this ecosystem using 15 years of electrofishing data and stable isotope analysis. We investigated the population trends of peacock eels at the marsh-mangrove ecotone of the Shark River Estuary, the environmental factors contributing to their abundance, and the potential interactions they may have with native fish assemblages and coastal food webs. We used stable isotope analysis to provide insights into the basal resource contribution to peacock eels and hypervolume analysis to determine peacock eel trophic niche size and overlap with native species. Results of this study found that peacock eel abundance has rapidly increased, and their populations are strongly related to hydroclimatic regimes. Peacock eel abundance was positively associated with warmer water temperatures and greater marsh inundation periods. The trophic niche of peacock eels was significantly smaller in volume than that of native sunfishes (Lepomis spp.) indicating lower intraspecific resource use variability and suggesting a limited potential for inter-specific competition with these taxa. However, in recent years, the catch of peacock eels has outnumbered the catch of all native sunfishes combined. The feeding habits and pervasiveness of peacock eels in the coastal Everglades could lead to a decrease in abundance of benthic prey items targeted by peacock eels and alter food web dynamics in the system. Based on these data, peacock eel populations are predicted to continue to increase, highlighting the importance of continued monitoring of their potential impact on native fish assemblages and food webs.

Shellfishing, sea levels, and the earliest Native American villages (5000–3800 yrs. BP) of the South Atlantic Coast of the U.S

Shell ring archaeological sites are one of the most visible site types along the lower South Atlantic Coast of the United States. These cultural sites are large, circular to arcuate piles of mollusk shells with some reaching over three meters in elevation and over 100 m in diameter. They are comprised largely of mollusk shells (e.g., Eastern oyster, Crassostrea virginica), but also contain early pottery, nonhuman faunal remains, and other artifacts. Our work establishes that they represent the earliest widespread Native American villages occupied year-round in the Eastern Woodlands of North America. Significantly, our results from sea-level modelling and isotope geochemistry on mollusks establish that the inhabitants of these earliest villages (ca. 5000–3800 yrs. BP) lived within a fluctuating coastal environment, harvested certain resources year-round, and targeted diverse habitats across the estuaries. Both the growth and decline of these earliest villages are associated with a concomitant rise and lowering of sea level that impacted the productivity of the oyster reef fishery along the South Atlantic Coast. Despite these large-scale environmental changes, this research indicates that Native American fishing villages persisted along the coast for over 1000 years.

Complete mitochondrial genomes and phylogenetic analysis of native and non-native fishes in a national key wetland of China

Fish are considered objective indicators of environmental health and ecosystem stability. Establishing regional reference databases of mitochondrial genome sequences from local fish communities can significantly enhance fish monitoring using environmental DNA (eDNA) analysis. For non-native species, the eDNA technique provides early detection and rapid monitoring. It is also crucial to include fundamental genetic information for both native and non-native species in genetic databases. This study presents the complete mitochondrial genomes of 17 fish species inhabiting the Baiyangdian Basin, a national key wetland in China. The mitochondrial DNA of these fish was analyzed to investigate their characteristics, and their phylogeny was determined using maximum likelihood (ML) methods. Various analyses were performed, including the examination of nucleotide composition, evaluation of AT-skew and GC-skew, analysis of codon frequency, and determination of relative synonymous codon usage (RSCU) values, and assessment of selection pressure on protein-coding genes (PCGs). The analysis showed that all PCGs in all fish underwent purifying selection. Using Xenocyprididae as a representative, this study investigated the genetic selection tendencies of native and non-native fish species in the Baiyangdian Basin. Significant differences were found in five of the 13 PCGs: COI, COII, COIII, Cytb, and ATP8. Except for ATP8, the findings indicated that the genes of non-native species underwent stronger purifying selection during evolution compared to native species. Additionally, comparing the population ω values of non-native species to those of native species showed that the Cytb and COIII genes exhibited greater differential purification selection than COI and COII. These differences may be the result of the evolution of non-native species to migrate and adapt to the Baiyangdian Basin, thereby affecting the evolution of related genes.

Evaluating fish foraging behaviour on non-indigenous Asparagopsis taxiformis using a remote video foraging system

The proliferation of pest and invasive marine macroalgae threatens coastal ecosystems, with biotic interactions, including direct effects such as grazing and indirect effects such as the trophic cascades, where one species indirectly affects another through its interactions with a third species, play a critical role in determining the resistance of local communities to these invasions. This study examines the foraging behaviour and preference of native fish communities toward native (Halopteris scoparia, Sargassum vulgare) and non-indigenous (Asparagopsis taxiformis) macroalgae using the Remote Video Foraging System (RVFS). Fifty-four weedpops were deployed across three locations to present these macroalgae, while associated epifaunal assemblages were also collected. Video analysis revealed that four common fish species displayed preference towards native macroalgae, possibly due to by the presence of zoobenthos rather than herbivory. This observation suggests that these fish species identified the macroalgae as a habitat that harboured their preferred food items. In contrast, A. taxiformis was consistently avoided, suggesting limited integration into the local food web. Site-specific variations in fish-macroalgae interactions and epifaunal diversity highlighted the complexity of these dynamics. This study contributes to understanding of the ecological implications of invasive macroalgae and supports the use of RVFS as a tool for assessing local biotic resistance against non-indigenous species in coastal ecosystems globally.

Survey of the invasive alien pink salmon (Oncorhynchus gorbuscha) for infective agents in the Fennoscandian Rivers Tana and Neiden

Pink salmon (Oncorhynchus gorbuscha, Walbaum 1792) is an invasive alien species in the Fennoscandian rivers, and its growing populations cause concern for their impact on the native salmonids and river ecosystems. One of the major concerns is fish diseases and the potential ability of pink salmon to transmit pathogens to the native salmonid species. In this study, pink salmon were sampled during their spawning migration in the Rivers Tana and Neiden in northern Norway and Finland in 2021. The fish were surveyed for viral hemorrhagic septicemia virus (VHSV), infectious pancreatic necrosis virus (IPNV), infectious salmon anemia virus (ISAV), salmonid alphavirus (SAV), piscine orthoreovirus (PRV), Renibacterium salmoninarum, and Gyrodactylus salaris. No viral diseases or infections with R. salmoninarum or G. salaris were detected. However, 23 % of the fish were found infected with a parasitic roundworm, Hysterothylacium aduncum. Additionally, external anomalies, such as hemorrhages or lesions in the skin, were observed in 35 % of the fish studied, and some of the fish exhibited degenerative myopathy. Based on this study, pink salmon appears not to pose a high infection risk to the native salmonid fish populations in the Rivers Tana and Neiden. Nevertheless, the results demonstrate that pink salmon have the potential to carry salmonid pathogens. More information on the susceptibility of pink salmon to different pathogens and on the overall effect this invasive species has on native fish species is needed. As the number of migrating pink salmon in the Fennoscandian rivers appears to increase, the potential risk of parasites and other pathogens spreading between fish species will also rise.

The native fish diversity with environmental influencing factors in the Daqing River basin, China

IntroductionInvestigating and assessing native fish diversity and conducting regional assessments of threats are vital for the conservation of aquatic biodiversity. For this specific study, the Daqing River basin in China was chosen as the research area. Field surveys were carried out between 2018 and 2019, supplemented by a review of pertinent literature and other records.MethodsTo evaluate fish diversity, the following parameters are selected for analysis: Relative abundance (Pi), Frequency of occurrence (Fi), Margalef richness index (D) , Shannon Wiener diversity index (H′) , and Pielou evenness index (J′).Relative abundance levels are categorized as follows: dominant species make up more than 10%, common species account for 1%–10%, and occasional species constitute less than 1%. Canoco 5.0 software was utilized to conduct Redundancy Analysis (RDA) on the fish species composition and environmental factors at 34 sampling sites.ResultsThe findings revealed that 85 fish species have been recorded in the basin, consisting of 78 freshwater species categorized into 8 orders, 17 families, and 59 genera, among which Cypriniformes comprised 64% of the total catch. The low proportion of threatened and endemic species was an important feature of the fish diversity of the Daqing River. Despite the theoretical presence of 85 species, field surveys managed to collect only 42 species, of which 33 were confirmed as naturally occurring within the basin. The average values of Margalef richness index, 22 Shannon Wiener diversity index and Pielou evenness index were 1.72, 2.04 and 0.80 respectively, signifying a low fish diversity with relatively uniform distribution across the sampled regions.DiscussionThis study found that the community structure and diversity of fish were closely related to environmental factors, particularly water quality. Among these factors, ammonia nitrogen emerged as a significant determinant of fish diversity. High concentrations of ammonia nitrogen inhibit fish growth, endanger health, and can even lead to death. Additionally, dams and other water infrastructure also impact fish community structure and diversity. This baseline study can provide a basis for the protection and ecological restoration of fish resources in the Daqing River.

Long-term evaluation of the impact of urbanization on native and non-native fish assemblages

Long-term evaluation of the impact of urbanization on native and non-native fish assemblages

The evaluations of oxidative stress and neurotoxicity in threatened endemic fish Barbus meridionalis from Osor River (Spain)

Mediterranean barbel (Barbus meridionalis) an endemic species is currently facing habitat destruction and pollution in Osor River (Spain) due to mining runoff that has severely deteriorated the water quality by metals, primarily zinc (Zn). In order to assess the potential risk of metal contamination and hydrological changes in the Osor River by using oxidative stress and neurotoxicity biomarkers via IBR analyses in the barbel, five different stations were chosen: upstream (S1: reference site and S2: hydrologically changed), mine (S3), and downstream (S4 and S5). The highest tissue metal levels were measured particularly at S3 and following downstream sites. SOD activity and the GSH system parameters (GPX, GST, and GSH) were the most sensitive oxidative stress indicators among the antioxidant system parameters. The organs with the greatest changes in antioxidant biomarkers were the liver and gill. As a sign of neurotoxicity, AChE activities significantly raised in the brain and muscle but drastically lowered in the kidney, liver, and gill particularly in the area of mine and downstream compared to reference site. Integrated biomarker response index (IBR) method was applied to visualize the affect of metal and hydrological alterations with biomarker response according to sites in the Osor River. IBR analyzes together with correlations between metal levels and oxidative stress biomarkers, emphasized that S2 and S3 have the greatest impact on the biomarker levels due to mine activity and hydrological changes highlighting the vulnerability to extinction of native fish B. meridionalis. It is also critical to assess the current data based on the multi-biomarker approach for a range of detrimental effects on fish fitness at the individual level as well as population persistence from an ecological standpoint.

New Record of Threatened Fish Species of Clupisoma naziri from River Gomati of Tripura, India

Morphometric and meristic characteristics of Clupisoma naziri was explored in Gomati River Tripura and the poorly known C. naziri, was newly recorded from the river at 23°33.144’N, 91°36.732’ E, elevation 39 m and 23°31.676’N, 91°39.184’ E, elevation 30m. Morphometric measurements (8 Male and 4 female) show the mean length and weight of the fish is 29.3±3.4cm and 246 ±7.1g respectively. Meristic counts show 40–45 anal-fin rays which is one of the important distinguishing characters of the species. The average water pH of the sampling site observed 6.7–7.2. Dissolved oxygen observed 5.6–6.4 mg/l, Total alkalinity 55–56 mg/l and Transparency observed 15–25 cm. Graphical Abstract Clupisoma naziri is currently considered near threatened by IUCN criteria, and therefore, it is urgent to take conservation measures and to study biological parameters of the fish to protect the fish in nature as well as in culture.