Fish Condition Research Articles

Growth And Food Habits Of Pelian Fish Tor Douronensis Caught Using Tuba Root Poison In Krayan Nunukan, North Kalimantan

The use of semah fish with the local name pelian fish in nature is carried out using various methods, one of which is using tuba root plant poison. This tuba root poison is thought to have an impact on the biological condition of pelian fish and aquatic ecology. In connection with this, this research aims to analyze the size distribution, growth type and food habits of pelian fish. The research was conducted from June to August 2023 in West Krayan District, Nunukan Regency, North Kalimantan. The results of the study showed that the length distribution of pelian fish caught using tuba root plant poison was 30.626 ± 7.048 cm, with a weight of 786.531 ± 430.066 g. The growth pattern is negative allometric with eating habits consisting of moss at 44.57%, insects at 33.04%, pieces of fruit at 10.00% and unidentified at 12.39%. Moss and insects are the main food, while fruit is a complementary food. Based on the results obtained, pelian fish in nature can be caught using moss bait. The use of high doses of tuba root can cause damage to the fish's gills, which can cause fish death as a result of not being able to neutralize rotenone.

Identifying minimum freshwater habitat conditions for an endangered fish using life cycle analysis

AbstractIdentifying the most important factors affecting population growth in animal life cycles is an important tool of species conservation. Delta Smelt (Hypomesus transpacificus), an annual fish endemic to the San Francisco Estuary in California (USA), has been provided legal protection since 1993 but 30 years later exists in a conservation‐reliant state on the brink of extinction. Despite considerable controversies about what factors are most responsible for the species' decline, no population growth rate sensitivity comparisons between the most important factors regulating growth have been done. Nor has anyone attempted to quantitatively identify habitat conditions needed to support positive population growth. We developed a set of stage‐structured population models to link habitat indices regulating recruitment of new generations of fish as they metamorphosed into juveniles and the subsequent survival of those fish over several seasons until they reached adulthood. These models are used to quantify drivers of growth rate variation over 30 years. Several complimentary sensitivity analyses indicated freshwater outflow to the estuary during summer had the largest potential to change population growth. Multiple habitat metrics (e.g., food availability, temperature) influencing recruitment and life stage specific survival rates across different seasons interacted in nonlinear ways to determine habitat conditions and water management targets associated with positive population growth. We discuss the implications for freshwater management, Delta Smelt conservation, and the challenges climate change poses for co‐implementation of these two societal priorities.

Mitigation of ammonia concentrations for improving wet, live fish and crab transport conditions

The transport of live aquaculture species, both throughout the culture period and during marketing as live products, is far from optimized. In wet transports, the bottleneck is the total ammonia nitrogen (TAN) concentration that develops in the transport water. The effect of actively removing TAN from the water on the survival of fish and crabs during wet transport is herein reported. The TAN concentration was controlled by exchanging NH4+ with Na+ using self-synthesized polymer-coated zinc-hexa-cyanoferrate (Zn-HCF) cation-exchange material. Theoretical simulation followed by empirical experiments were carried out to mimic the transports of Gilthead seabream and European Brown crab, in the presence and absence of Zn-HCF. The Zn-HCF proved very efficient: while the TAN concentration in the seabream test tanks did not exceed the predetermined 5 mgN/L value (throughout the work), the control tanks showed much higher values. In the Brown Crab experiment the control had to be stopped after 2.3 days to avoid animal welfare issues, while the test completed the full 4.8 d. Yet, the crabs from the Test tanks exhibited much higher survival rates following 24 and 48 h dry packing. The results show unequivocally that the addition of Zn-HCF to wet transfer tanks can improve the vitality of the shipped animals, allow to extend the transfer periods and/or increase the shipment density.

Sargassum sp. extract improve hematological profile of tilapia fish (Oreochromis niloticus)

Background Strategies to increase body resistance and prevent disease in aquaculture include using vaccines, antibiotics, and probiotics. Today, the use of antibiotics with natural ingredients is becoming a trend. Sargassum sp is a natural ingredient that contains high antioxidants and antibiotics. Methods This research was conducted from March to May 2022 at the Biotechnology Laboratory, Faculty of Fisheries and Marine, Universitas Riau, in two stages: 1) the sensitivity of extracts of Sargassum sp. and 2) the application of Sargassum sp. extract orally in tilapia (O. niloticus). The parameters measured were clear zone, minimum inhibitory concentration, LD50 test of leaf extract of Sargassum sp. in tilapia (O. niloticus), hemoglobin levels, hematocrit, total leukocytes, total erythrocytes, leukocyte differentiation, and survival rate. Data on hematology parameters were tabulated and analyzed using a One-Way ANOVA followed by a Student Newman Keuls (SNK) test when deemed necessary. Results The results showed that the extract of Sargassum sp. inhibited the growth of Aeromonas hydrophila bacteria with a clear zone of 6.5-15.0 mm, which is classified as resistant. At doses of 2000, 2500, and 3000 ppm, it did not cause death in fish for 96 hours (LD50). Hematological parameters can be a sign of the health status of fish. Tilapia given Sargassum sp. in different doses gave an effect between treatments after 30 days of rearing and post-test against A. hydrophila bacteria (p<0.05). The results showed that the hematology of fish fed with Sargassum sp. extract was in the normal or healthy range. Healthy tilapia had erythrocyte counts ranging from 1.34-2.11×106 cells/mm3, hematocrit 26.17-33.19%, hemoglobin 6.26-11.2 g/dL and total leukocytes 1.01-1.50×104 cells/mm3 and total erythrocytes 5.88-9.13×104 cells/ mm3. Conclusions A dose of 3000 ppm provided the highest health improvement against A. hydrophila bacterial infection.

Effects of metformin on wild fathead minnows (Pimephales promelas) using in-lake mesocosms in a boreal lake ecosystem

Due to its widespread use for the treatment of Type-2 diabetes, metformin is routinely detected in surface waters globally. Laboratory studies have shown that environmentally relevant concentrations of metformin can adversely affect the health of adult fish, with effects observed more frequently in males. However, the potential risk to wild fish populations has yet to be fully elucidated and remains a topic of debate. To explore whether environmentally relevant metformin exposure poses a risk to wild fish populations, the present study exposed wild fathead minnows (Pimephales promelas) to 5 or 50 μg/L metformin via 2 m diameter in-lake mesocosms deployed in a natural boreal lake in Northern Ontario at the International Institute for Sustainable Development - Experimental Lakes Area (IISD-ELA). Environmental monitoring was performed at regular intervals for 8-weeks, with fish length, weight (body, liver and gonad), condition factor, gonadosomatic index, liver-somatic index, body composition (water and biomolecules) and hematocrit levels evaluated at test termination. Metabolic endpoints were also evaluated using liver, brain and muscle tissue, and gonads were evaluated histologically. Results indicate that current environmental exposure scenarios may be sufficient to adversely impact the health of wild fish populations. Adult male fish exposed to metformin had significantly reduced whole body weight and condition factor and several male fish from the high-dose metformin had oocytes in their testes. Metformin-exposed fish had altered moisture and lipid (decrease) content in their tissues. Further, brain (increase) and liver (decrease) glycogen were altered in fish exposed to high-dose metformin. To our knowledge, this study constitutes the first effort to understand metformin's effects on a wild small-bodied fish population under environmentally relevant field exposure conditions.

Maximization of brackish water productivity for the sustainable production of striped catfish (Pangasianodon hypophthalmus) and grain sorghum (Sorghum bicolor (L.) Moench) cultivated under an integrated aquaculture–agriculture system

Freshwater scarcity, salinity, and poor soil fertility are the major challenges affecting both food and feed productions in arid and semi-arid regions of the world. Utilization of brackish water in the production of saline-tolerant fish and valuable field crops under an integrated system is promising in the maximization of yield per crop. The aim of this study, therefore, was to (1) assess the effect of saline aquaculture wastewater on the growth, yield, forage quality, and nutritive composition of sorghum seeds and (2) assess the effect of different water qualities on the survival, growth performance, and health status of Pangasianodon hypophthalmus. The experiment was conducted in a randomized completely block design of four salinity treatments with three replicates, i.e., control (freshwater mixed with inorganic fertilizers), 5000 ppm, 10,000 ppm, and 15,000 ppm. Our results indicated that although the control exhibited the highest growth (plant height, leaf number, internode number, leaf area, and soil–plant analysis development), grain, and forage yield, no significant differences were noted among the treatments. Likewise, no significant difference in the grain nutrient composition was noted among all the treatments. Assessment of the forage quality revealed improved crude protein content in the control compared to the saline treatments. However, no significant differences in the leaves and stalks fiber fractions were noted among all the treatments. Furthermore, rumen fermentation in terms of in vitro digestibility indicated no significant differences in the in vitro digestible dry matter, digestible organic matter, metabolic energy, net energy, microbial protein, short-chain fatty acids, and total dissolved nutrients among the treatments. However, rearing P. hypophthalmus in water salinities exceeding 10,000 ppm reduced the growth performance and health status of fish. Therefore, the integration of sorghum and P. hypophthalmus production in water salinities not exceeding 5000 ppm is a viable alternative to maximize brackish water productivity in freshwater-scarce regions.

Summarizing quantile estimates of weight at length to compare condition: Geographic and temporal variation in Arctic Grayling

AbstractObjectiveWe developed a novel, simple approach to summarize variation in quantile regression estimates of weight at length across multiple levels of grouping factors (locations or years) and demonstrate its utility for comparing fish condition using Arctic Grayling Thymallus arcticus data. We compared condition among 28 geographic locations of Arctic Grayling populations and among 12 and 25 years for two populations.MethodsWe summarized variation among locations and among years within locations using percentiles (maximum, 75th, 50th, 25th, and minimum) of predicted quantiles of weight at length, allowing us to simplify the distributions of predicted quantiles of weight into highest to lowest fourths (quartiles) across locations or years. One part of this summary information, 75th percentiles of median (0.50 quantile) predicted weights at length across populations, is identical to summary statistics used to develop standard weight equations for computing relative weights. However, our approach avoids biases inherent in fitting a single standard weight equation and can accommodate among‐fish variation in weight at length via multiple quantiles when developing reference standards for comparative or diagnostic purposes. A selected new weight at length can be compared with the distribution of quantile predictions among locations in terms of weights or as proportionate weights similar to relative weight.ResultArctic Grayling in 28 geographic locations, from the southern limit of their distribution in Montana and Wyoming north through Canada and Alaska to the Arctic coast, had considerable variation in allometric exponents in weight–length relationships and in predicted weights at length. Predicted weights of Arctic Grayling for heavier fish (0.90 quantiles) in populations with less (lower quartiles) to greater (upper quartiles) weights were 127–194 g and 336–510 g at total lengths = 250 and 350 mm, respectively. Lighter fish (0.10 quantiles) in populations with less to greater weights were 100–133 g and 259–364 g, at the same total lengths, respectively. We provide statistical code and tabled values that can be used as reference standards as a replacement for standard weight equations for comparing new samples of fishes. We also quantified annual variation in condition within two intensively sampled populations, the Kuparuk River in Alaska (25 years, 1985–2012) and Red Rock Creek, Montana (12 years, 1994–2016). Annual distributions of weights at length were greater for Arctic Grayling in Red Rock Creek than those in the Kuparuk River. Variation in predicted distributions of weights at length among years was also greater for Red Rock Creek, although fish from both locations exhibited substantial among‐year variation that exceeded half the variation estimated among geographic locations.ConclusionOur estimates indicated that there was substantial spatial and temporal variation in condition of Arctic Grayling that might be investigated further to help understand constraints on populations to aid conservation and management of the species. Our summary approach can be easily extended to other investigations of fish weight at length relationships where multiple quantile estimates are made across many levels of grouping factors.

Evaluating streamflow and temperature effects on Bull Trout migration and survival with linear spatial capture–recapture models

AbstractObjectiveIn the U.S. Pacific Northwest, climate change is increasing air temperatures, decreasing warm season (April–September) streamflow, and increasing cool season (October–March) streamflow. Warmer water temperatures may alter conditions for migratory coldwater fishes like the Bull Trout Salvelinus confluentus. Consequently, an understanding of Bull Trout migration and survival is critical for species conservation and restoration. In the Salmon River basin, Idaho, 1992 and 1993 transpired to be two of the most opposing extreme years among the past three decades for warm season water temperature and streamflow. These extremes provided a unique opportunity to retrospectively compare Bull Trout survival and migration under potential climate change scenarios.MethodsWe evaluated prespawning and postspawning migrations and survival of fluvial Bull Trout that were radio‐tagged and tracked from 1992 to 1994. We used a Cormack–Jolly–Seber linear spatial capture–recapture model to simultaneously model the migration and survival of radio‐tagged prespawn (n = 58) and postspawn (n = 23) Bull Trout among weeks and river reaches with streamflow, water temperature, and habitat covariates.ResultMost individual prespawning migrations were similar among tagged fish, whereas postspawn fish adopted multiple migration and overwintering strategies. Movements of prespawn Bull Trout were larger when (1) weekly average daily maximum streamflow increased and (2) weekly average daily maximum water temperature increased. The model estimated that at least 52% of spawners survived to spawning, and mean weekly prespawning apparent survival was higher in the low‐streamflow year (1992) than in the year with higher and more variable streamflow (1993). Survival of 1992–1994 fish during the 38‐week postspawning period was intermediate to that in the prespawning period. Detections of prespawn Bull Trout were generally higher at sites with more complex habitats, less large woody debris, and fewer undercut banks.ConclusionWe found that the prespawn life stage can represent a shorter time frame (14–18 weeks) with increased mortality compared to the longer postspawning period (38 weeks). Bull Trout apparent survival increased with lower streamflow variability, indicating that expected future changes in climate may adversely affect Bull Trout.

Maximum storage time of refrigerated blood and frozen plasma samples from tambaqui, Colossoma macropomum

Blood analysis is an important tool for monitoring the health status of fish, but the time between collection and analysis can affect the outcome of the analysis. This study sought to determine the maximum time refrigerated blood and frozen plasma samples of the tambaqui, Colossoma macropomum, can be stored without affecting analysis. Samples from 12 fish were obtained, stored under refrigeration at 4 °C and evaluated after 0, 24, 48, 72, and 96 h, while samples from 14 fish were centrifuged, and the resulting plasma was frozen at −20 °C and then evaluated after 0, 8, 12, 16 and 20 weeks. The parameters analyzed were hematocrit (Ht), hemoglobin content (Hb), total erythrocytes (RBC), total (WBC) and differential leukocytes, total thrombocytes (TC), glucose content (Glc), total protein (TP), triglyceride content (TG), total cholesterol (CoT), and the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). For refrigerated whole blood samples, mean corpuscular hemoglobin content (MCHC) showed a transient decline in 24 h, and there were decreases in WBC, TC, Glc and TG that persisted until the 72 h sample point (for Glc and TG) or persisted until the 96 h sample point (for WBC and TC). A decrease in RBC was noted from 48 h on, while ALT was significantly higher in the 96 h sample. Significant decreases in lymphocytes, monocytes, neutrophils and eosinophils were noted from 48 h of storage on, while a significant decline in basophil counts were noted over the last two sampled timepoints. The coefficient of variation was greatest at the 96 h timepoint, indicating increased variability in measured parameters after 4 d of refrigeration. Plasma samples frozen at −20 °C showed a significant variation in ALT after 8 weeks, and increases in TP and TG after 20 weeks. Therefore, it is recommended that refrigerated tambaqui whole blood samples be analyzed within 24 h and frozen tambaqui plasma samples analyzed within 8 weeks.

Motile aeromonas septicaemia infection in African catfish ( Clarias gariepinus , Burchell, 1822): A review

Abstract African catfish, Clarias gariepinus, is among the important fish species cultured in sub-Saharan Africa. Because of the high stocking densities commonly seen in culture facilities, disease-causing organisms such as Aeromonas hydrophila is prevalent among cultured C. gariepinus . A. hydrophila is one of the Gram-negative bacteria commonly encountered in an aquatic environment worldwide. The organism has been associated with several disease conditions in fish including tail rot, fin rot and haemorrahagic septicaemia. The bacterium also infects a variety of aquatic, terrestrial and arboreal animals including man. The objective of this study was to systematically review the relevant literature on A. hydrophila infection in C. gariepinus . The study has analysed the current status of the disease, its epidemiology, clinical manifestations and pathology, and suggested methods to mitigate its impacts on fish production, especially in low-income developing countries.

Species diversity and conservation status of ornamental fish traded in Kupang, East Nusa Tenggara, Indonesia

Abstract. Usman Z, Hariyadi DR, Serihollo LGG. 2024. Species diversity and conservation status of ornamental fish traded in Kupang, East Nusa Tenggara, Indonesia. Biodiversitas 25: 1116-1126. The high demand for ornamental fish native to Indonesia has the potential to be used as a source of foreign exchange income. In addition to increasing the national income, the ornamental fish trade must also be considered to preserve the population of the fish species being sold. The study aimed to determine ornamental fish diversity and conservation status in Kupang City, East Nusa Tenggara. This research was conducted in Kupang City, East Nusa Tenggara, Indonesia, from August to September 2023. The research was conducted using survey (non-experiment) and observation methods. The survey method was carried out using a form to conduct interviews with sellers in 11 ornamental fish shops. At the same time, the observation method was used to identify the types of fish being traded. The study's results recorded 18 families, 39 genera, and 46 fish species (Include 1 species is hybrid fish). The highest species diversity came from the Cichlidae family with 9 species (1 species (Amphilophus citrinellus x Cichlasoma trimaculatum) is hybrid fish), followed by Cyprinidae with 7 species, whereas each species of the Characidae and Poecilidae families were 5 species. Conservation status shows 4 status groupings, namely Least Concern (LC), Vulnerable (VU), Endangered (EN), and Not Evaluated (NE). Based on these groupings, there were 32 species in the Least Concern (LC) category, 3 species in the Endangered (EN) category, 2 species in the Vulnerable (VU) category, and 8 species in the Not Evaluated (NE) and 1 unclassified category. There is only 1 species that is included in the Appendix I category, namely Scleropages formosus, and other species are Not evaluated. This is the first study conducted in Kupang City to reveal the types of ornamental fish species sold and their conservation status. The study will be useful information to the government, researchers, and other stakeholders on the potential extinction risk of each type of fish being traded.

Analysis of Feeding Habits and Biological Aspect of Yellow Stripe Trevally (Selaroides leptolepis) Caught at the Lekok Coast, Pasuruan, East Java

The fish population in waters can decrease due to the uncontrolled utilization of fish resources. Food is one of the determining factors for the population and condition of fish in the waters. Considering the economic and ecological importance of the yellow trevally in food webs, this research was conducted to analyze the feeding habits and biological aspects of the yellow trevally in Pesisir Lekok. This study used a descriptive data analysis with complete randomized design. The research was conducted from May to July 2023 at Pesisir Lekok, Pasuruan, East Java. The results showed that the yellow trevally is carnivorous with the dominant food found being zooplankton from the genus Microcalanus sp. with a frequency of occurrence of 41%. The highest plankton composition found in the stomach of the yellow trevally was the phytoplankton of the Aulacoseira genus, which was 22.2%. Meanwhile, the foods most preferred by the yellow trevally are Rotifera and Charophyta with an index value of +1. The biological aspect of the yellow trevally seen from the length-weight relationship shows that the growth pattern of the yellow trevally is negative allometric with a b value of 2.651. While the condition factor range average values are 1.009 – 1.027. The results of this study are expected to be the basis for efforts to support the sustainable management of fisheries resources, especially the yellow trevally in the coastal waters of Lekok.

Living with hypoxia: Residence and site fidelity by golden perch (Macquaria ambigua) in habitats affected by methane seeps and chronic hypoxia

Abstract We conducted an acoustic telemetry study of native golden perch (Macquaria ambigua) to examine movement behaviour in areas affected by methane seeps and hypoxia in the intermittent Condamine River, Murray‐Darling Basin (MDB), Australia. Fish were collected during periods of no flow and hypoxia (dissolved oxygen [DO] <1 mg/L). Despite these conditions, 38 of 43 fish tagged with acoustic transmitters were detected for >3 months post‐tagging in the study reach and 27 fish were being detected after 14 months. During periods of elevated river flow and relatively high DO, 30 fish moved away from their original tagging locations, with three undertaking movements (>7 km) outside the study reach and not returning. Generalised additive mixed models showed a significant increase in the probability of movement as soon as flow commenced and when water temperatures exceeded 19°C. As flows receded, most fish that had moved exhibited accurate homing behaviour to their original tagging location. The patterns of movement and site fidelity exhibited by golden perch correspond with previous studies of the species in intermittent rivers not affected by methane seeps and severe hypoxia, suggesting that the methane seeps and hypoxia did not inhibit fish movement nor render the affected habitats unsuitable for habitation. Golden perch can survive and remain active in water with much lower DO (<1 mg/L) than previously described for large‐bodied native fishes in the MDB. However, fish condition in the study reach was slightly lower than other regions of the MDB, providing preliminary evidence that fish residing in habitats affected by chronic hypoxia and methane seepage may experience sub‐lethal stress. Our results demonstrate the importance of field‐based data on the behavioural and physiological responses of fish to chronic hypoxia and methane exposure to guide appropriate management responses.

Isolation and Identification of Edwardsiella tarda from Catla (Catla catla), Koi (Anabas testudineus) and Tilapia (Tilapia mosumbicus)

Edwardsiellosis is a very common fish disease in framed fish caused by Edwardsiella tarda which can lead a severe economic loss in aquaculture worldwide. Isolation and identification of the pathogenic bacteria Edwardsiella tarda from three fish species: catla Catla catla, koi Anabus testudineus and tilapia Tilapia mosumbicus were undertaken from different area of Mymensingh District. The intestine, liver and kidney of each fish were inoculated into Salmonella-Shigella (SS) plates and TSA plates. The colonies of the SS plates were subcultured onto TSA plates and undergone specific identification processes through their morphological and biochemical tests for Edwardsiella tarda. They were Gram negative, rod shaped, motile, oxidase negative bacteria that showed positive reactions for catalase and fermented glucose. Quantitative studies of the bacterial flora of the above fishes on TSA plates showed that the minimum total bacterial load of tilapia was 1.50 × 102 cfu/g in the blood and the maximum was 8.20 × 106 cfu/g in kidney. In case of catla, the minimum load was 2.36 × 103 cfu/g in the blood and the maximum was 8.20 × 106cfu/g in intestine. Koi showed its minimum load of 2.45 × 103 cfu/g in the blood and a maximum of 5.54 × 105 cfu/g in liver. It was understood that the bacteria Edwardsiella tarda is an opportunistic pathogen in Bangladesh aquaculture and can, any time be a cause of serious disease condition of culture fishes of Bangladesh at least in catla, koi and tilapia.

Infeksi Ektoparasit dan Korelasinya dengan Panjang, Berat, dan Faktor Kondisi Benih Ikan Mas Merah Najawa (Cyprinus carpio Linneaus)

One of the problems in commona carp farming activities is ectoparasite infection which is thought to correlate with length, weight and condition of the fish. The aims of the research were to determine the species, prevalence, intensity and dominance of ectoparasites and to determine the correlation between the number of ectoparasites and the length, weight and condition factors of Najawa red carp (Cyprinus carpio Linneaus) fingerling at BPTPB Cangkringan. The research used laboratory observation method on randomly selected fish samples. Sampling was carried out for 3 weeks and a total of 27 individuals were examined. Ectoparasite observations were carried out on mucus samples from the body surface and gill sheets microscopically. The length and weight of each fish sample were measured and the results were used to calculate the condition factor. The correlation relationship was calculated between the number of ectoparasites and the length, weight and condition factors of the fish. The research results showed that five ectoparasites were found to infect fish samples with varying prevalence and intensity values, namely Trichodina sp., Dactylogyrus sp., Gyrodactylus sp., Glochidium sp. and Vorticella sp. Trichodina sp. has the highest prevalence, intensity and dominance compared to other parasites. The number of ectoparasites has a positive correlation with the length and weight of fish in the low category. In addition, a low negative correlation was found between the number of ectoparasites and fish condition factor. The results of this study indicate that ectoparasites are a factor that can influence the productivity of Najawa red carp cultivation.

Impact of Hydroxytyrosol-Rich Extract Supplementation in a High-Fat Diet on Gilthead Sea Bream (Sparus aurata) Lipid Metabolism.

High-fat diets (HFDs) enhance fish growth by optimizing nutrient utilization (i.e., protein-sparing effect); however, their potential negative effects have also encouraged the search for feed additives. This work has investigated the effects of an extract rich in a polyphenolic antioxidant, hydroxytyrosol (HT), supplemented (0.52 g HT/kg feed) in a HFD (24% lipid) in gilthead sea bream (Sparus aurata). Fish received the diet at two ration levels, standard (3% of total fish weight) or restricted (40% reduction) for 8 weeks. Animals fed the supplemented diet at a standard ration had the lowest levels of plasma free fatty acids (4.28 ± 0.23 mg/dL versus 6.42 ± 0.47 in the non-supplemented group) and downregulated hepatic mRNA levels of lipid metabolism markers (ppara, pparb, lpl, fatp1, fabp1, acox1, lipe and lipa), supporting potential fat-lowering properties of this compound in the liver. Moreover, the same animals showed increased muscle lipid content and peroxidation (1.58- and 1.22-fold, respectively, compared to the fish without HT), suggesting the modulation of body adiposity distribution and an enhanced lipid oxidation rate in that tissue. Our findings emphasize the importance of considering this phytocompound as an optimal additive in HFDs for gilthead sea bream to improve overall fish health and condition.

The concept of "state fishes of India": Current status, knowledge gaps, and strategic plans for conservation and sustainable utilization.

The concept of "state fishes of India" highlights the importance and significance of the prioritized fish species distributed across various states within the country. This review article systematically documents the current status of state fishes from various perspectives, identifies the prevailing knowledge gaps, and also highlights the issues and strategic plans essential for the conservation and sustainable utilization of these valuable genetic resources. A total of 8357 publications were checked for the consolidated information on state fish species, and the appropriate items were selected under eight categories: biology, physiology and nutrition, aquaculture, habitat and environmental parameters, genetics and biotechnology, harvest and postharvest, fish health management, and others. The synthesized information was used to present the current status of research and development on state fish species. The knowledge gaps that are to be addressed are also depicted under the perspectives of fisheries management and conservation aquaculture. Based on the findings, strategic plans for the targeted conservation programmes are proposed and discussed under various in situ and ex situ conservation measures. Further, the departmental processes involved in the declaration, the importance of stakeholder involvement, namely, local communities and policymakers, in fostering effective conservation measures, and planning for utilization of these valuable fish genetic resources are also indicated.

Состояние финансовой составляющей экономической безопасности рыбохозяйственного комплекса Приморского края

Unstable economic conditions in which the fishery complex operates intensify the impact of external and internal threats. External threats are sanctions pressure from European states, mainly related to re-strictions on the supply of fish products and equipment imports. Internal threats include high costs for the implementation of production activities, the unsatisfactory condition of fixed capital and the low rate of its renewal, unstable fishing conditions, etc. Negative trends that have formed over the past decades continue to adversely affect activities. Since the fish industry is a very significant industry, the lack of control over the state of its economic security can threaten the full food security of the population, as well as the functioning of many industries whose business is related to fish raw materials. The most significant indicators of the economic security of the fishery complex of Primorsky Krai are analyzed: the ratio of growth rates of net profit, revenue and asset value, the economic growth sustainability coefficient, indicators of the efficiency of the use of production resources, financial stability and solvency. Using analytical procedures, a quantitative assessment of the influence of factors on indicators with negative dynamics is given. An unstable change and a low level of the economic growth sustainability coefficient were revealed. The reason for this was the profitability of sales of fish products, insufficiently intensive turnover of own working capital, unsatisfactory solvency of organizations. Current assets are not enough to pay off debts, there is a high dependence on earthly sources of financing. Meanwhile, there is an improvement in the efficiency of the use of fixed capital, labor resources, which has developed under the influence of growth in revenue and profit; the profitability of products is increasing, the profitability of assets is low.

Climate change can impair bacterial pathogen defences in sablefish via hypoxia-mediated effects on adaptive immunity

Low-oxygen levels (hypoxia) in aquatic habitats are becoming more common because of global warming and eutrophication. However, the effects on the health/disease status of fishes, the world's largest group of vertebrates, are unclear. Therefore, we assessed how long-term hypoxia affected the immune function of sablefish, an ecologically and economically important North Pacific species, including the response to a formalin-killed Aeromonas salmonicida bacterin. Sablefish were held at normoxia or hypoxia (100% or 40% air saturated seawater, respectively) for 6–16 weeks, while we measured a diverse array of immunological traits. Given that the sablefish is a non-model organism, this involved the development of a species-specific methodological toolbox comprised of qPCR primers for 16 key immune genes, assays for blood antibacterial defences, the assessment of blood immunoglobulin (IgM) levels with ELISA, and flow cytometry and confocal microscopy techniques. We show that innate immune parameters were typically elevated in response to the bacterial antigens, but were not substantially affected by hypoxia. In contrast, hypoxia completely prevented the ∼1.5-fold increase in blood IgM level that was observed under normoxic conditions following bacterin exposure, implying a serious impairment of adaptive immunity. Since the sablefish is naturally hypoxia tolerant, our results demonstrate that climate change-related deoxygenation may be a serious threat to the immune competency of fishes.

Length-Weight Relationship and Condition Factor of a Commercial Food Fish Labeo rohita (Hamilton, 1822) from Ghaghara River, Uttar Pradesh, India

The present study provides first-hand information about the length-weight relation of Labeo rohita (Hamilton) from Ghaghara River, Uttar Pradesh. We collected 107 specimens and took length and weight for better conservation techniques and proper management for rohu. A total of 107 specimens were examined for the study, which has ranging from 25.2-56.13 cm TL (Total length) and 183.3-2409.78 gm (weight) were used for the study of LWRs and condition factors. Our study represented that L. rohita exhibited a negative allometric growth (b < 3) indicating that the fish grows faster in length compared to their weight. The values of the correlation coefficient (r2) and condition factor (K) are 0.8601 and 1.27 respectively. This research will be useful for fishery research, stock assessment, conservation, and estimation of the fish condition of this Himalayan River.