Native Fish Species Research Articles

Effects of Rapid Thermal Cycling (Cold Shock) on Fish Health: Evidence from Controlled Laboratory Experiments, Behavior, and Telemetry

Powerplants frequently use river water for cooling, subsequently discharging warm effluent. Some of these plants can cycle on and off rapidly based on electricity demand, resulting in dramatic temperature fluctuations in the receiving waters. To understand the impacts on resident fish populations in the Upper Mississippi River, we (i) assessed the effects of rapid water cooling on three native fish species; (ii) investigated whether smallmouth bass (Micropterus dolomieu) behavior favored movement into thermal plumes when given a choice of cooler or ambient water; and (iii) tracked native M. dolomieu with acoustic tags and recorded core body temperature during the thermal cycling process of a steam electric powerplant. In cold shock experiments, mortality was associated with rapid temperature declines and dependent on the final (cold) holding temperature. The species or developmental stage of the tested organism did not affect survival. When given a choice between warm and ambient waters, M. dolomieu exhibited little inclination to acclimate to the warmer water and instead “self-regulated” by moving in and out of the warm water plume. This finding was supported by telemetry data on M. dolomieu. The core temperature of the fish never increased more than 2 °C above the ambient (upstream) Mississippi River temperature, even during warm effluent discharge.

Economic valuation of ecosystem services trade-offs of tilapia cage culture farm and native capture fisheries in Lake Maninjau, Indonesia

Research on the effects of cage aquaculture on native fish populations has revealed its negative and positive impacts. However, a separate analysis of its ecological and economic effects creates incomplete information for the decision-makers. Moreover, the inadequacy of time series data has caused challenges to knowledge-based decision-making in establishing new cage aquaculture sites, especially in low-middle income countries. We use the ecosystem services (ES) framework to analyse the synergy and trade-off of cage aquaculture to a native fish species, Gobiopterus sp. in Lake Maninjau, Indonesia, as an effort to provide comprehensive information to support local decision-makers and to fill the information gap. We engaged some modelling techniques such as the Maximum Entropy Model (MaxEnt) validated with field survey data, Bayesian Networks (BN), and Monte Carlo Simulation (MCS) in this research. The results show that cage aquaculture provides habitat services for the species and temporary forgone fish production due to the accelerated sulfur upwelling. The economic value of habitat provision reached 74,500 IDR per year per cage or 1,128 million IDR per year in 2017. Further, the average value of the forgone benefit of fish production in the current cage aquaculture business extends from more than 550 million IDR per year in the dry season to almost 600 million IDR per year in the rainy season. The results indicate that the negative impacts of cage aquaculture on the native fish population outweigh its benefit. The recommendation for management actions includes applying alternative aquaculture techniques and other technological interventions.

Small-scale fishery catch composition in Rhodes (Eastern Mediterranean Sea)

Trammel net and boat-seine experimental fishing samplings were carried out seasonally, over a rocky-sandy and a Posidonia oceanica habitat respectively, in the coastal waters of Rhodes, south-eastern Aegean Sea, Greece, between 2019 and 2020. Fish catch composition, abundance and biomass were investigated as a contribution to the qualitative and quantitative monitoring of the fish assemblages in the artisanal fishery in this Greek marine region most affected by biological invasion. A total of 56 native and 11 alien fish species were captured. Five invasive species Fistularia commersonii, Pterois miles, Siganus rivulatus, Siganus luridus and Lagocephalus sceleratus were recorded using both fishing gear. In trammel nets, the alien to native fish species ratio was 1:2.87 with eight allochthonous species composing 43% of the total abundance and greatly exceeding native species biomass with the most dominant being F. commersonii, P. miles, S. rivulatus and S. luridus. Boat seine samples were dominated by Spicara smaris and Boops boops, which accounted for 84% and 56% of total abundance and biomass, respectively, while the alien to native fish species ratio was 1:5.1. The 10 Lessepsian fish, i.e., fish that have entered the Mediterranean Sea via the Suez Canal, identified on a Posidonia seabed represented a small proportion of the total abundance (3.4%), while their biomass reached 17% of the total catch, with a prevalence of F. commersonii. Among alien fish on P. oceanica, S. rivulatus exhibited the greatest abundance, followed by F. commersonii, Parupeneus forsskali and S. luridus, with small but not negligible densities of Pteragogus trispilus and Torquigener flavimaculosus. The abundance of Pterois miles over the rocky-sandy habitat was remarkable. Results indicate a transitional shift in fish catch composition with introduced species competing with natives for food and space (i.e. between introduced siganids and Sparisoma cretense, Sarpa salpa, between the recently introduced P. forsskali and mullids, and between introduced P. miles and scorpaenids), further influenced synergistically by environmental and anthropogenic factors. The Total-Standard length and Total weight-Total length relationships and their applications in fisheries data for the allochthonous fish are briefly discussed.

Catch dynamics of freshwater bram Abramis brama in the Ob river basin as a reflection of the success of its acclimatization

The native range of the freshwater bream Abramis brama includes the basins of the North, Baltic, White, Azov, Black, Caspian and Aral seas. This species is not a popular object of aquaculture, but it is cultivated in some countries of Eastern Europe and Central Asia. In the water bodies of Italy, Spain, Portugal, England and China, it is a naturalized alien species that does not have a large number. At first freshwater bream was introduced into the Ob basin in 1862, in the reservoirs of the eastern slope Urals. By the end of the 19th century, bream became common in this region, but spread slowly downstream: in the Lower Irtysh it was noted only in the mid-1920s, and entered the commercial statistics in 1936. It became known in the Middle Irtysh in the 1930s, but it became an object of fishing only in 1963. In the lakes of the Ob-Irtysh interfluve, at first bream was introduced in 1928. In the largest of them, it became naturalized. In the Ubinskoye lake the bream formed a stable self-reproducing population, which served as a source of juvenile bream for resettlement in water bodies of Siberia and Kazakhstan in the middle of the twentieth century. Currently, the bream in the Ubinskoye lake does not inhabit due to the shall owing of the lake. Bream was introduced into the Novosibirsk reservoir in 1957–1960. It quickly became numerous and began to spread up and down the river Ob. It has been known in the Upper Ob in the Altai Region since the early 1960s, and in the Middle Ob in the Tomsk Region since the end of the same decade. Currently, the catch of bream in the Ob basin are maximum in the Bukhtarma reservoir, relatively large in the Novosibirsk reservoir and in the water bodies of the Khanty- Mansiysk Autonomous Region. At the same time, the share of this species in the total volume of fish catch in large reservoirs of the Ob basin is about 80% of the fishing, in the Middle Ob and Middle Irtysh — about 20%, and in the north of Western Siberia — less than 0.5%. The decrease in the share of bream in the fishery from south to north reflects not only a decrease in the abundance of this species in the latitudinal direction, but also an increase in the stocks of native fish species.

Exploring YOLOv8 Pretrain for Real-Time Detection of Indonesian Native Fish Species

The main objective of this research is to determine the efficacy of the YOLO model in detecting native fish species found in Indonesia. Indonesia has a variety of maritime natural resources and shows significant diversity. This research utilizes the YOLO architecture, previously trained on several datasets, for fish detection in the environment in Indonesian waters. This dataset consists of various fish species native to Indonesia and was used to retrain the YOLO Pretrain model. The model was evaluated using test data that accurately represents Indonesian water conditions. Empirical findings show that the modified YOLO Pretrain model can accurately recognize these fish in real-time. After utilizing YOLO and Pre-Train with Ultralytics YOLO Version 8.0.196, the results show an accuracy of 92.3% for head detection, 86.9% for tail detection, and an overall detection accuracy of 89.6%. The fish image dataset, consisting of a total of 401 images, is categorized into three subsets: the training dataset, which consists of 255 images; the validation dataset, which includes 66 images; and the testing dataset, which contains 80 images. This research has great potential for application in fisheries monitoring, marine biology research, and marine environmental monitoring. A real-time fish detection system for the Identification and tracking of fish species is carried out by researchers and field workers. The findings of this research provide a valuable contribution to ongoing efforts aimed at conserving marine biodiversity and implementing more sustainable management practices in Indonesia.

Haplotype Diversity in the Mitochondrial COI Gene of Barred Rainbowfish (Chilaterina fasciata) from Mamberamo River of Western New Guinea, Indonesia

A Barred rainbowfish (Chilatherina fasciata) is one of the native fish species found in Western New Guinea of Indonesia. This study aimed to observe the levels of haplotype diversity in the partial Cytochrome-c oxidase subunit I (COI) gene of Barred rainbowfish. For the DNA analysis, thirty (30) Barred rainbowfishes were caught from the Mamberamo River. Three (3) molecular packages of BioEdit, MEGA, and DNAsp were used to analyze twenty (30) forward sequences of the COI gene (502 bp). The research showed four (4) haplotypes for the examined population, a total of seven (7) mutations, and low genetic diversity detected in the partial COI gene with the haplotype diversity (Hd) = 0.405 and nucleotide diversity (pi) = 0.003. Meanwhile, the Fu's and Tajima's tests were 1.21 and -0.69, respectively. The UPGMA tree with 1,000 × bootstrap replications revealed that Barred rainbowfishes are grouped into similar clusters with Melanotaenia vanheurni, Chilatherina alleni, and Chilatherina bleheri. In conclusion, haplotype 3 (77%) was detected as the common haplotype for Barred rainbowfishes at the Mamberamo River of Western New Guinea.

Habitat suitability of Unionidae host fish in the Rhine Delta

Unionid populations are declining worldwide as they are threatened by anthropogenic habitat alterations, the introduction of invasive alien species and the effects of climate change. Several studies have focused on the habitat preferences of adult mussels but none to date have reported on the importance of the habitat preferences of host fish species. The aim of this study was to determine the habitat preferences of unionid host fish species in the Netherlands, to examine potential differences between native and alien host fish species, and to evaluate the effect of alien host fish species on unionid dispersal. Species sensitivity distributions (SSDs) were constructed for the range of occurrences and laboratory tolerance of host fish species in the Netherlands for water temperature, substrate type, flow velocity, and water depth. A case study was selected to assess the suitability to substrate type, flow velocity and water depth of a novel river habitat along longitudinal training dams in the river Waal. Unionid host fish species in the Netherlands preferred shallow littoral zones (0.1 m) with low flow velocity (0.05 m/s), an average water temperature of the Rhine delta (15°C), and most substrate types (ranging from silt to cobbles). Boulder substrate was the most limiting factor of the abiotic factors assessed for both native and alien host fish species. Management options for unionid populations should include host fish species in their assessments while focusing on creating and maintaining areas with limited boulders and implementing alien host fish species removal measures.

Vanishing splendor: a comprehensive review of the decline in the original fish fauna of Lake Victoria

The presence of the non-native Nile perch (Lates niloticus) in Lake Victoria and the resulting ecological transformations have garnered significant attention from the scientific community. However, details regarding the timing, origin, and purpose of the fish introduction have remained elusive. This paper reviews fish fauna changes in Lake Victoria, investigates causes, and advocates for biodiversity conservation through diversity and sanctuary sites. It examines different historical periods to understand changes and guide effective conservation strategies. The introduction of Nile perch has led to a substantial decline and even extinction of many native fish species, particularly cichlids, resulting in ecological imbalances and economic challenges for local fishing communities. To address these pressing issues, ongoing conservation efforts are being implemented. These initiatives focus on promoting sustainable fishing practices, safeguarding critical habitats, and reintroducing native fish species. Furthermore, cage fish farming is being explored as a potential solution to alleviate pressure on wild populations, as suggested by various authors. Recommendations stemming from this study include conducting virtual population analysis for stock assessments of indigenous species, intensify conservation efforts, diversify fishing practices, expand cage fish farming, increase public awareness and education, and enhance policy and governance frameworks. By implementing these recommendations, there is optimism for the recovery and resilience of indigenous fish species in Lake Victoria, leading to the conservation of biodiversity and the promotion of sustainable livelihoods for local communities.

Bioconcentration of carbamazepine, enalapril, and sildenafil in neotropical fish species.

Sewage effluents are the main source of entry of Human Pharmaceutical Active Ingredients (HPAIs) to surface water bodies. Carbamazepine (CBZ), psychiatric drug, enalapril (ENA) antihypertensive, and sildenafil (SIL), to treat erectile dysfunction, have been frequently detected in receiving wastewater and in wild fish species from Argentina. This study aimed to assess the bioconcentration of selected HPAIs in native fish species of the Del Plata Basin. In a first trial, the bioconcentration factors of CBZ, ENA, and SIL were obtained by exposing Cnesterodon decemmaculatus, respectively, to 135, 309, and 70μg/L during 96h. Then the bioconcentration kinetic of SIL was comparatively assessed in C. decemmaculatus and Piaractus mesopotamicus exposed, respectively, to 44.1 and 16.2μg/L during a one-week, followed by a four-day depuration phase. HPAIs concentrations in water and tissue were measured by HPLC-MS after 0.22μm filtration and direct injection or solid-liquid extraction, respectively. Bioconcentration factors obtained empirically (BCFe) for C. decemmaculatus were CBZ = 1.5, SIL = 1.4, and ENA = 0.007. Parameters estimated by the SIL bioconcentration kinetic model for C. decemmaculatus were: uptake rate constant (k1) = 5.5L/kg d, elimination rate constant during uptake phase (k2u) = 0.00175 d-1, maximum predicted tissue concentration (Ct(max)) = 138588μg/kg, estimated bioconcentration factor (BCFm) = 3143, lag time between the exposure and the first detection in tissue (tlag) = 0 d, elimination rate constant in the depuration phase (k2d) = 0.49 d-1 and half-life in the tissue (t1/2) = 1.4 d. The model parameters for P. mesopotamicus were k1: 7.3L/kg d, k2u: 0.0836 d-1, Ct(max): 1423μg/kg, BCFm: 88, tlag: 3.8 d in the uptake phase and k2d: 0.31 d-1 and t1/2: 2.3 d in the depuration phase. The reached conclusions were: 1) the bioconcentration capacity of CBZ and SIL are similar but around 200 times higher than ENA, 2) the time to reach the bioconcentration equilibrium for SIL is longer than 1week, then estimated BCFm are between 1 and 3 orders of magnitude higher than BCFe obtained after 96h exposure, but actual values need to be verified, 3) substantial differences (≈30 fold) were observed in the estimated BCF of SIL among species, indicating the need for further studies toward understanding such diversity to improve HPAIs ecological risk assessment worldwide.

Bighead carp Aristichthys nobilis and silver carp Hypophthalmichthys molitrix in the Southern Western Siberia

The native range of the bighead carp Aristichthys nobilis and silver carp Hypophthalmichthys molitrix covers the East Asian river basins from the Amur to the Yangtze. These are inhabitants of large streams with a developed floodplain. These species spawn in rivers, during pronounced fluctuations in the water level, at high flow rates. A. nobilis and H. molitrix, as well as their hybrids, are widely used in aquaculture in many countries of the world. It is believed that the A. nobilis does not naturally reproduce in most places of introduction, but it is known that it successfully naturalized in the Amur river basin. Natural reproduction of the H. molitrix occurs in some rivers in Eurasia and America. In Russia, it is currently known about the natural reproduction of A. nobilis and H. molitrix in the Lower Volga and in the Kuban river. In new habitats, the bighead carp, as a zooplankton feeder, can be a food competitor for juveniles of native fish species. The naturalization of silver carp can pose a serious threat to recipient ecosystems, since it feeds on phytoplankton and it can significantly undermine one of the lower elements of the trophic chain of water ecosystems. The first introduction of A. nobilis and H. molitrix in the Ob river basin was made in 1958, in the Novosibirsk reservoir. Currently, these species are cultivated in fish farms in the region, from where they enter natural water bodies. Data on the natural reproduction of A. nobilis and H. molitrix in the Ob river basin (except, possibly, the Belovsky reservoir) is currently absen

Using social-ecological models to explore stream connectivity outcomes for stakeholders and Yellowstone cutthroat trout.

Despite growing interest in conservation and re-establishment of ecological connectivity, few studies have explored its context-specific social-ecological outcomes. We aimed to explore social and ecological outcomes to changing stream connectivity for both stakeholders and native fish species impacted by habitat fragmentation and nonnative species. We (1) investigated stakeholder perceptions of the drivers and outcomes of stream connectivity, and (2) evaluated the effects of stakeholder-identified connectivity and nonnative species scenarios on Yellowstone cutthroat trout (YCT) populations. Our study was conducted in the Teton River, Idaho, USA. We integrated two modeling approaches, mental modeling and individual-based ecological modeling, to explore social-ecological outcomes for stakeholders and YCT populations. Aggregation of mental models revealed an emergent pattern of increasing complexity as more types of stakeholders were considered, as well as gaps and linkages among different stakeholder knowledge areas. These results highlight the importance of knowledge sharing among stakeholders when making decisions about connectivity. Additionally, the results from the individual-based models suggested that the potential for a large, migratory life history form of YCT, in addition to self-preference mating where they overlap with rainbow trout, had the strongest effects on outcomes for YCT. Exploring social and ecological drivers and outcomes to changing connectivity is useful for anticipating and adapting to unintended outcomes, as well as making decisions for desirable outcomes. The results from this study can contribute to the management dialogue surrounding stream connectivity in the Teton River, as well as to our understanding of connectivity conservation and its outcomes more broadly.

Swimming under Pressure: The Sub-Lethal Effects of a Pesticide on the Behaviour of Native and Non-Native Cypriniformes Fish

River ecosystems are exposed to a multitude of stressors, including increasing pesticide run-off driven by precipitation and irrigation. Pyrethroids are the fourth major group of insecticides in use worldwide and have extremely negative effects on aquatic fauna. In this study, we aimed to assess the effects of an acute 2 h sub-lethal exposure to different levels of the pyrethroid esfenvalerate on the swimming behaviour of two Cypriniformes species: the native Iberian barbel (Luciobarbus bocagei) and the non-native invasive bleak (Alburnus alburnus). The experimental set-up consisted of previous exposure to three esfenvalerate concentrations (control, 1.2 (low), and 2.0 (high) μg/L) before being stocked in a three-artificial-flume-channel mesocosm for behavioural trials through direct observation. Monitored behaviours included (i) routine activity, (ii) shoal cohesion, and iii) boldness. Significant differences in fish behaviour were detected for the native species (barbel), as individuals spent significantly more time holding position (i.e., resting) in the control (44.9%) than in the high esfenvalerate concentration (25.2%). Concordantly, control barbels were also found to perform more directional changes than the ones exposed to high esfenvalerate concentrations. Behavioural changes were also found for boldness, measured by the proportion of fish attempts to negotiate the upstream ramp, which were significantly higher in the control (37.4%) and in the high concentration (41.5%) compared to the low one (21.1%). Finally, regarding shoal cohesion of the barbel, it was tighter in the control (81.3%) than in the low- (70.5%) and high- (71.1%) esfenvalerate treatments. For the invasive bleak, there were no significant differences in any of the behavioural traits upon previous exposure to an increasing esfenvalerate concentration. This experimental study demonstrated that even short-term exposure to the pyrethroid esfenvalerate was sufficient to alter the behaviour of a native Cypriniformes fish species while not affecting the non-native species. This may confer greater competitive advantages to non-native fish species in the context of global changes.

Effect of river restoration on spawning activity of Iberian barbel (Luciobarbus bocagei)

In fluvial systems, where aquatic organisms are limited to living within river networks, anthropogenic barriers can interrupt connectivity and contribute to habitat fragmentation. Habitat connectivity is particularly important for migratory fish that need to move considerable distances for spawning, rearing, and refuge areas. In order to support crucial stages in the native fish species’ life cycles, compensatory measures were established in the Vilariça River due to the construction of the Baixo Sabor Hydroelectric Scheme (BSHS). Thus, the purpose of this work is to evaluate if the implemented measures, such as habitat-enhancing weirs and a flow bypass system releasing water from the BSHS, improved the survival and reproduction of a native species, the Iberian barbel (Luciobarbus bocagei). The assessment included the calculation of the number of spawning individuals and the Weighted Usable Area (WUA) of spawning habitat. In addition, to assess spawning activity, a spawn-per-unit-effort (SPUE) methodology was developed. The results showed that migration and spawning of L. bocagei were improved by increased flow velocity from the bypass system. The installed weirs also contributed to spawning success because they allowed the establishment of resting and spawning areas that were essential during reproductive period. It was possible to estimate the maximum SPUE of 5.4 spawns per minute at the spawning grounds with a 20 m reach and the number of fish observed, which ranged between 251 and 800 per fieldwork at the spawning grounds and resting areas. Furthermore, the maximum WUA was estimated to be 1580 m2 for a discharge of 1 m3/s (between median and maximum flow for spawning season) at a 2 km reach of the Vilariça River. This work showed that the rehabilitation of a tributary of a fragmented river due to the construction of dams was a valid compensatory procedure because it allowed the migration and spawning of the fish.

A flooded future for River Chub? Future impacts of climate change and urbanization on reproduction of a keystone native fish species

AbstractObjectivePredicted impacts of climate change in the eastern United States are pervasive and complex, including increased precipitation, increased frequency of heavy precipitation events, and altered seasonality of rainfall. This will potentially lead to increased flooding frequency and severity. The River Chub Nocomis micropogon is an important keystone and engineer species in the eastern United States, primarily through its construction of nesting habitat, which is shared with other species (“nest associates”) in a mutualistic relationship. River Chub nests are vulnerable to high flows caused by excessive precipitation and by urbanization of watersheds. Using predictions of climate change models, we examined the potential for increased River Chub nest disruption under two climate change scenarios.MethodsPublished thresholds linking River Chub nest disruption with stream discharge were used to interpret fine‐scale predictions of a downscaled climate prediction model (HadGEM2‐ES) using a stochastic weather generator (LARS‐WG6) calibrated to two climate change scenarios. This was examined for a case study watershed (Big Elk Creek, Maryland). The amount of River Chub nest disruption was compared between present‐day stream discharge observations (1995–2021) and simulated data for 2061–2080 under the “worst case” (RCP85) and “probable‐case” (RCP45) scenarios. Potential nest disruption in an urbanized stream that lost its River Chub (Gwynns Falls, Maryland) was also evaluated for comparison with Big Elk Creek scenarios.ResultSignificantly elevated nest disruption under both RCP45 and RCP85 relative to observed current conditions was found under status quo watershed characteristics in the form of more disruptive events, more disrupted days, and shorter periods of disruption‐free days during the River Chub nesting season. Potential nest disruption in the urbanized case study stream was far greater than that observed for any scenario.ConclusionIncreased nest disruption projected by the downscaled HadGEM2‐ES climate prediction model was moderate and far below the level of nest disruption observed in flashy urbanized streams that have lost or may have lost River Chub populations in the region. The moderate impacts of increased flooding from climate change will interact with projected population growth and urbanization for the Big Elk Creek watershed. Mechanistic modeling of fine‐scale processes by using stochastic weather generators shows promise for modeling the responses of ecosystems to changing conditions.

Morphological and Trophic Features of the Invasive Babka gymnotrachelus (Gobiidae) in the Plain and Mountainous Ecosystems of the Dniester Basin: Spatiotemporal Expansion and Possible Threats to Native Fishes

Over the last few years, the racer goby B. gymnotrachelus quickly expanded in the mountainous rivers of the Dniester basin at aheight of 300 m a.s.l. and above. The occurrence frequency of the racer goby in fish communities in the mountainous rivers of the Carpathian ecoregion remains low (up to 20%), as compared with the plain rivers, where the species occurs in 70–100% of cases. The major prey groups in its diet in both plain and mountainous were Chironomidae, Diptera, and Crustacea. Chironomidae formed the maximal portion (35% at an occurrence frequency of 72.5%), and Trichoptera formed 18%at an occurrence frequency of 41%, whereas fish larvae were absent in their diet in mountainous rivers. The peculiar environmental conditions of mountainous rivers caused the adaptive modifications of the morphological features of the racer goby at the subpopulation level, which compriseda decrease inthe specimens’ size in rivers with a flow velocity of above 1.5 m/s and rivers with pebble contentsof above 50%in the bottom sediments.The modifications showed an increase inbody streamlining as an adaptation to flow velocity and turbulence and the stony substrate of the river’s bottom. Thus, the morphological adaptation of B. gymnotrachelus to the conditions of the mountainous rivers is in progress, and the formationof astable population in these rivers can be expected. In contrast, the native fish species’ resilience in the face of newcomers is still high, and this is because their alevins are not food for invaders.

Proximal and mineral composition of native fish species from Amazonas, Brazil

For decades, researches were developed about the diversity of fishes in the Amazon basin and their consumption by the people. In this context, an important gap identified was a lack of information about the nutritional composition of some of the main Amazon fish species consumed and traded. Front this, the objective of this study was to evaluate the chemical composition and mineral content of filets from 10 fish species with the highest landing volume in Amazonas State. The fish species selected were curimatã, jaraqui, mapará, matrinxã, pacu, piramutaba, sardinha, surubim, tambaqui and tucunaré. Were collected 20 samples (fishes) from each species according to the hydrological cycles of the region (20 samples in the flood and 20 samples in drought). Ten fish samples were processed to determine the proximal composition and 10 fish samples were used to determine mineral content (macro and micro minerals). The proximal composition of fish species analysed varied widely between species and seasons, with an emphasis on moisture and lipid content. Fishes in the flood season presented higher content of nutrients than drought season. This result also was observed in the minerals profile, where fishes in the flood season presented the highest (p < 0.05) minerals content.

A trait-based approach to determine the risks of Zn to the overall health status of native fish species Barbus meridionalis

Fish adapt to changing environments by maintaining homeostasis or making energy trade-offs that impact fitness. We investigated the effect of Zn on the fitness and physiology of Barbus meridionalis, a native cyprinid fish species, under two exposure scenarios. The Osor stream's mine-effluent reach represented long-term (chronic) exposure, while the upstream reach served as a control/acute exposure. Acute exposure involved exposing B. meridionalis to 1mg/L Zn for 96 h in the laboratory. We examined physiological traits (Standard metabolic rate SMR, Maximum metabolic rate MMR, Absolute Aerobic scope AAS, Critical swimming capacity Ucrit) and antioxidant system, AS (Superoxide dismutase, SOD; Catalase, CAT; Glutathione peroxidase, GPX; Glutathione-S-transferase, GST; Glutathione, GSH; Thiobarbaturic acid reactive substances, TBARS) biomarkers. The results indicated that Zn had no significant effect on osmoregulatory cost (SMR) in either exposure scenario but impaired energetically costly exercise (low MMR). AAS reduction in both exposure groups suggested compromised energy allocation for life-history traits, evidenced by decreased locomotor performance (Ucrit) after acute exposure. Tissue-specific and time-dependent responses were observed for AS biomarkers. The fish exhibited ineffective control of oxidative damage, as evidenced by high TBARS levels in the liver and gills, despite increased CAT and GSH in the liver under acute conditions. Our findings demonstrate differential responses at the subcellular level between the two exposure scenarios, while trait-based endpoints followed a similar pattern. This highlights the utility of a trait-based approach as a supplementary endpoint in biomonitoring studies, which provides insights into impacts on individual fitness and population demography.

The Evolution of Trout Stream Management in the Black Hills, 1883–2023, as Evidenced Through Hatchery Activities and Stocking

In this paper, we review and synthesize trout management philosophy and policies for Black Hills streams in the states of South Dakota and Wyoming through the roles of hatcheries, fish stocking, and natural production from 1883 to 2023. We identified three specific fisheries management time periods (eras) in the Black Hills: (1) the early management–fry stocking era (pre‐1950), (2) the catchable‐trout stocking era (1950s to mid‐1990s), and (3) the integrated management era (mid‐1990s to present). The first era emphasized juvenile trout stocking, with little evaluation of effectiveness in terms of return to creel. The second era was characterized by greater emphasis on stocking catchable‐sized trout and a substantial increase in hatchery rearing capabilities. In the first two eras, instead of fish stocking being one of many potentially useful tools for managers of Black Hills streams, stocking was the dominant activity—leading and directing fisheries management rather than supporting it. By the third era, trout management began to embody a more encompassing and complex national ideology and philosophy that more fully considered ecology, including habitat improvement, natural reproduction of trout, defining the role of fish stocking, and understanding the relationship of trout to the depauperate native (nongame) fish fauna. We also discuss the three eras in the Black Hills in relation to national trends in trout management. In contrast to many other localities, the lack of any native salmonids and the lack of native game fish species have facilitated the development of valuable, self‐sustaining recreational fisheries in streams that support trout, with less concern for native species than in many areas with harvestable native fish species. The cultural ideology that brought western expansion of settlers to the Black Hills in search of gold, land, freedom, and prosperity was emboldened by a science‐based belief and confidence in technology and industry to rapidly shape lands and waters to improve the human condition. In part, the sculpting and shaping of Mount Rushmore symbolize that ideology. In the context of fisheries management in the Black Hills, the introduction of trout, development of stream fisheries, and investment in hatchery technology to produce catchable trout for an expanding tourist economy also exemplify that prevailing ideology, modulated by improved ecological understanding and an accompanying shift toward a more ecological management philosophy.

Evaluation of a Prefabricated Fish Passage Design for Great Plains Fishes

Connectivity is critical for stream fish persistence, and fish passage structures are a useful conservation tool to reconnect fragmented systems. The design of fish passage structures is a tradeoff between the area available for construction, slope, and costs associated with the structure. The Longrie–Fecteau fish passage structure was designed to be modular, adjustable to barrier-specific needs, and to have a low slope (2%) to pass small-bodied fishes. We evaluated fish passage through this structure in Fountain Creek, Colorado, USA, via a PIT tag mark–recapture study. We documented four native Great Plains fish species successfully ascending the passage structure, with most passage occurring at night. We estimated a 3% probability of a released fish entering the structure, then 89% and 99% passage to the midpoint and exit of the 123 m structure, respectively. Low entrance efficiency was due to low recapture probability of small-bodied study organisms in a relatively large system, and the low percentage of space of the entryway on this barrier (<3% of the length of the barrier). Fish that entered the structure ascended quickly, with median time for successful ascent of 19 min, and minimum time of 6 min. The Longrie–Fecteau fish passage structure is a conservation tool that may broaden the adoption of fish passage structures for small-bodied fishes due to its modularity and low slope.

Growth patterns and reproductive aspect of Naleh (Barbonymus sp.) in Krueng Lanca, Nagan Raya Regency, Aceh Province

Naleh (Barbonymus sp.) is one species of native fish found in Aceh Waters. This study examines the growth patterns and reproductive aspects of the fish in Krueng Lanca of Nagan Raya, Aceh Province. The study lasted five months (January - May 2022). Sampling was carried out purposively, once a month, on five different stations using gill nets (mesh size: 0.5 inches, 1.0 inches, and 1.5 inches and cast nets (D: 6 meters, mesh size: 0.5 inches). A total of 171 Naleh was caught in these waters. The calculation results obtained a length-weight relationship W = 0,0003*L2.2234 (r2 = 0.8823) for males, which shows the nature of allometric and W = 6E-06*L3.0684 (r2 = 0.8566) for females which shows the isometric. The sex ratio of Naleh in these waters was 1.1: 1. The size of the first mature gonads was 60-69 mm (males) and 90-99 mm (females) with a Gonadosomatic Index of 1.92-3.04 % (Males) and 8.73-11.61 % (females). The peak of the Naleh spawning season in Krueng Lanca waters was thought to occur from March to April, with the number of eggs ranging from 1,853-3,813 and a diameter of 1.18-1.43 mm. Based on the oocyte distribution, the peak of spawning of the fish was categorized as multiple spawners.