Fish Condition Research Articles

The Evolution of Three Schizothoracinae Species from Two Major River Systems in Northwest China Based on Otolith Morphology and Skeletal Structure.

Schizothoracinae species are the largest group of Cypriniformes that readily adapt to the natural conditions of the Qinghai-Tibet Plateau. This group has habitat characteristics and distribution patterns centered on the Qinghai-Tibet Plateau. To study the evolution of three Schizothoracinae species in Northwest China, the evolutionary characteristics of these species were explored based on differences in otolith morphology and skeletal morphology. From 2020 to 2022, 138 samples (63 Aspiorhynchus laticeps, 35 Diptychus maculatus and 40 Schizothorax pseudaksaiensis) were collected from the Tarim River and Ili River, 6 basic morphological parameters of otoliths were measured and converted into 6 morphological factors and 7 morphological indices. A total of 77 Fourier transform coefficients of each otolith were selected The first three principal components accounted for 92.834% of the total variation in 13 otolith morphological indices of the three Schizothoracinae species, and the overall discrimination rate was 94.20%. According to the principal component analysis of 77 Fourier harmonic values of otoliths, the first 20 principal components explained 97.233% of the total variation, and the overall discrimination rate was 100%. The results of the cluster analysis directly reflected the relationships between related species. The differences in the bone morphology of the three Schizothoracinae species were particularly reflected in the number of whiskers, pharyngeal teeth and vertebrae, and there were also significant differences in the shapes of the sphenotic (SP), pterotic (PTE), preoperculum (PO), branchiostegal ray (BRA) and basibranchial (BB) bones. Their unique morphological and skeletal characteristics are closely related to geological changes and water system evolutionary trends. This study contributes to the understanding of species identification and the evolutionary status of plateau fishes, provides a reference for further evolutionary classification and for assessing the evolutionary mechanisms of plateau fishes, and provides a scientific basis for phylogeny and germplasm resource protection.

Diversity pattern of ichthyofaunal assemblage in South-central coastal region of Bangladesh

The south-central coastal waters of Bangladesh are recognized as one of the foremost aquatic biodiversity hotspots despite severe anthropogenic and environmental hazards to natural fishery resources. Therefore, this study was undertaken to examine the current status of fish faunal diversity and evaluate the condition and conservation status of fish in the rivers spanning the south-central coastal region of Bangladesh. During the research period, spanning from July 2021 to February 2022, a total of 105 fish faunal species belonging to 84 genera, 50 families, and 14 orders were documented. The order Perciformes (27.62%) was found to be the most diverse fish group, followed by Cypriniformes and Scombriformes (12.38%), Siluriformes and Clupeiformes (11.43%), Synbranchiformes and Pleuronectiformes (3.81%). According to the International Union for Conservation of Nature (IUCN) Red List classification, 52 species recorded from the studied areas were determined to be of Least Concern, while 11 species were Vulnerable, 14 species were classified as Endangered, and 7 species are recognized as Critically Endangered. In order to assess the species diversity, richness, and evenness of the fish assemblage in the sampling areas, four diversity indices, viz. the Shannon-Wiener index (H), Simpson’s dominance index (D), Simpson’s index of diversity (1-D), and Margalef’s index (d), were applied. Their overall values were 3.39–3.59, 0.05–0.07, 0.95–0.94, and 7.67–8.75, respectively. All of the species were more or less evenly distributed throughout the three sites, with Kalapara having the most even distribution. Several anthropogenic and natural attributes that contribute to decline in fish diversity were recorded using a survey questionnaire which revealed that management and conservation measures should be taken with utmost urgency.

Lipids as biomarkers to assess the nutritional and physiological status of two diadromous fish (Anguilla anguilla and Chelon auratus) at early life stages in a temperate macrotidal estuary.

Estuaries are considered as key habitats for the early life stages of fish. However, in the face of massive destruction of many estuarine intertidal areas, management and conservation measures are needed. Fish condition indicators may be used as a proxy of habitat quality and provide valuable information for management of coastal areas. In this study, the larvae of golden mullet (Chelon auratus) and European glass eels (Anguilla anguilla) were sampled in three sites of the Gironde Estuary. Different lipid classes and fatty acids were quantified: phospholipids (globally, phosphatidylethanolamine and phosphatidylcholine), triglycerides, omega-3 (particularly docosahexaenoic and eicosapentaenoic acids), omega-6 and C18:1. These biomarkers provide information on the nutritional status of the larvae as well as on prey availability and larvae diet between sites. One site significantly differed from the others as it seemed to offer abundant and better-quality prey. The very high levels of omega-3 contained in mullet larvae suggested that this site provided a high amount of diatoms. However, the mullet larvae that colonized this site also showed physiological stress that could be explained by exposure to pollutants through their prey. This work constitutes an essential baseline for developing biomarkers to assess the quality of habitats in a global change context.

Мікрорівнева адаптація окремих органів і тканин стерляді (Acipenser ruthenus Linnaeus, 1758) в умовах теплового стресу

Purpose. To evaluate the variability of the histological parameters of individual organs and tissues of sterlet, to establish the level of effect of heat stress on the physiological status of fish and the degree of their adaptation. To determine the perspective of using histological monitoring data in fish farming practice. Methodology. The primary materials were obtained in aquarium conditions of the Aquatic Bioresources Laboratory of the Kherson State Agrarian and Economic University. The laboratory processing of histological samples was performed according to generally accepted methods and manuals. Histological studies were carried out using the author’s equipment and original methods, specially intended for the diagnostics of fish tissues. The obtained results were processed by methods of variational statistics using a package of appropriate MS Excel applications, with emphasis on the standard error. Findings. Microanatomical studies of sterlet showed that under conditions of heat stress, the most significant changes occur in adipose tissue, somatic and cardiac muscle tissue, thyroid gland and renal tissue, which can conditionally be considered as bioindicative zones. Under the potential influence of the thermal factor, the response of sterlet is expressed in a decrease in the lipid content in the accompanying muscles of adipose tissue. The effect is visualized in the fragmentation and subsequent shredding of lipid vacuoles, which leads to variability in adipocyte shape from stellate to spindle-shaped. The obtained results indicate a decrease in the excretion of thyroid hormones into the bloodstream by the thyroid gland and is expressed in a gradual increase in the diameter of the thyroid follicles (by 16.0 µm and 26.5 µm) and a corresponding decrease in the height of the follicular cells (by 1.1 µm and 2.0 µm), which is statistically significant. Intensive development of “additional” follicles inside existing ones indicates the prevention of thyroid intoxication of the body, which indicates the development of an adaptive reaction of the body. Comparative studies of the ventricular myocardium of fish allowed establishing certain morphological differences in the form of moderate interstitial edema of the tissue and intracellular edema of cardiomyocytes. In the final phase of the experiment, karyopyknosis was locally observed in the ventricular cardiomyocytes of 50% of stressed fish. Somatic muscle tissue is generally resistant to stress, but the rate of its development at elevated temperatures slows down. Characteristic signs of the histological picture of muscle stress are approximately the same ratio of stromal and parenchymal components, the central orientation of the nuclei within a single muscle fiber and insufficient filling of the fibers with the fibrillar component. Antidiuretic hormone is forcedly released in fish under conditions of heat stress, which leads to a decrease in the volume of the primary filtrate. Evidence is a narrow gap in the urinary space between the visceral and parietal layers of the renal corpuscle. Originality. New data are presented and existing data on the histological structure of individual organs and tissues of sterlet under stress loads are significantly expanded. For the first time, a detailed histological analysis of the structure of muscle, adipose tissue, as well as the kidney and thyroid gland of sterlet under heat stress conditions was carried out. The comparative analysis, current and updated information on compensatory changes in tissues demonstrate their adaptive potential, which was developed during the evolution of the species. Practical Value. The information obtained is of value in morphophysiological studies as well as in fish farming practice in connection with the modern problem of a decrease in the life status of fish under stress. The use of the obtained data allows a qualitative assessment of the physiological state and can be used in the process of developing corrective measures in order to consolidate hereditary resistance, which is ultimately aimed at preventing diseases of valuable aquaculture objects. Keywords: sterlet, heat stress, adaptation, muscle tissue, thyroid gland, myocardium, adipose tissue, renal tissue.

Effect of bicultural rearing of pikeperch (Sander lucioperca) and Russian sturgeon (Acipenser gueldenstaedtii) on growth and fish condition parameters in RAS

This study investigated the intensive rearing of pikeperch (Sander lucioperca) and Russian sturgeon (Acipenser gueldenstaedtii) in a recirculating aquaculture system for 84 days, with five different stocking ratios (with P as a percentage of pikeperch): P100, P90, P80, P70, and P0. The growth parameters, fish condition parameters, and blood biochemistry were measured. The P70 group showed the highest final total length, standard length, and body weight of pikeperch (82.95 ± 18.92 g), while the lowest values were found in Groups P100 (63.46 ± 18.49 g) and P90 (68.63 ± 13.79 g). The sturgeon did not show significant differences, except for Group P90, which had the lowest body weight (86.10 ± 33.95 g). Survival rates were high for pikeperch (96.098.6%) and no mortality in the sturgeon was evident in all groups. The feed conversion ratio (FCR) for pikeperch was similar between Group P100 (0.88 ± 0.02) and the two bicultural groups P90 (0.80 ± 0.04) and P80 (0.69 ± 0.05). For the sturgeon in Group P0, had a comparable FCR (0.71 ± 0.13). The lowest FCR for sturgeon was observed in the bicultural group P70 (0.66 ± 0.03). Tissue-somatic indices, hepatosomatic index (HSI), and fat-somatic index (FSI), supported significant differences only for pikeperch, with the highest values for the P80 and P70 groups. This study of pikeperch and Russian sturgeon rearing in various stocking ratios for 84 days demonstrates optimal growth and health parameters in the P70 group for pikeperch, with overall high survival rates and minimal health variations in sturgeon, suggesting the effectiveness of a mixed species approach in recirculating aquaculture systems.

Oxidative processes in the immunocompetent organs of pink salmon Oncorhynchus gorbuscha and chum salmon Oncorhynchus keta (Salmonidae) during the marine period

The influence of various factors on the fish body is reflected in changes in metabolic processes, including an imbalance of redox processes. The study of the level of oxidative processes and antioxidant protection in the tissues of aquatic organisms is often used in ecological and ecologicaltoxicological studies to assess the environmental conditions. Obtaining such data when conducting comprehensive ichthyological studies makes it possible to assess the features of adaptation to various habitat conditions, as well as the health status of fish. Mature pink salmon Onchorhynchus gorbuscha and chum salmon O. keta were caught in the summer of 2018 in the open waters of the northwestern Pacific Ocean (east of the Kuril Ridge) using a mid-water trawl during a trawl survey. Immediately after catching, liver, kidney and spleen samples were taken from the fish. Test tubes with organ tissue samples were frozen at –20 °С. Homogenates were prepared from thawed organ samples under laboratory conditions. The level of lipid peroxidation products and antioxidant activity was evaluated. As a result, intertissue and interspecific similarities and differences in the studied parameters of pink salmon and chum salmon during the marine period of life were established. The detected differences in indicators are presumably related to the structural and functional organization of the tissues and organs studied, as well as species characteristics. The results can be used to monitor population health and compare with closely related species.

Capture–translocation restores spawning migration connectivity of Razorback Suckers in the fragmented San Juan River

AbstractObjectiveBarriers to movement negatively affect population vital rates of riverine fishes that rely on connected migratory routes to complete components of their life cycle, such as reproduction and recruitment. In the southwestern United States, decades of water diversion, construction of large impoundments, and loss of floodplain habitats have all contributed to highly fragmented riverscapes. A capture–translocation strategy was implemented for Razorback Suckers Xyrauchen texanus in the San Juan River to mitigate the negative effects of two barriers while precluding the upstream movement of nonnative species. We hypothesized that translocated individuals would remain upstream of barriers during the spawning season and that aggregations of translocated Razorback Suckers would be identified upstream in spawning habitats.MethodsWe used radiotelemetry to assess movement of Razorback Suckers after translocation above the two barriers. We deployed fixed remote radio receivers to determine residency time above each barrier and conducted mobile telemetry surveys to monitor upstream destinations after translocation.ResultAlthough most Razorback Suckers returned downstream of barriers within 2 months of translocation, we provide evidence that most individuals remained upstream long enough to successfully spawn. After translocation above the Piute Farms Waterfall, 80% of individuals remained upstream for 26 days in 2020 and for 23 days in 2021. Further upstream (307 km), at a weir operated by the Public Service Company of New Mexico, 80% of translocated individuals remained above the barrier for 37 days in 2021 and for 25 days in 2022. After fish translocation above both barriers, we observed upstream movements ranging from 2 to 262 km and we detected distinct aggregations within the expected spawning season.ConclusionAlthough translocation efforts seasonally reconnect migratory routes for a proportion of the population and may increase spawning potential, other conservation actions are likely still needed to improve recruitment conditions for juvenile fish.

Recruitment of European sea bass (Dicentrarchus labrax) in northerly UK estuaries indicates a mismatch between spawning and fisheries closure periods.

European sea bass (Dicentrarchus labrax) is a species of high commercial and recreational value, but it exhibits highly variable recruitment rates and has been subject to recent declines. Emergency management measures put in place to protect spawning stocks include the annual closure of commercial and recreational fisheries over a 2-month, February-March, window. Whether this protection measure is having the desired outcome for this data-poor species remains unclear. Otolith microstructural analyses (counts and widths of daily growth rings and check marks indicative of settlement) were used to estimate (1) spawn timing, (2) pelagic larval duration and settlement timing, (3) growth rate and condition, and (4) the otolith-fish size relationship for juvenile European sea bass caught from two estuaries in Wales (Dwyryd, Y Foryd), located at the northern edge of the species range. We observed a significant mismatch between the timing of fisheries closures and the spawning, with 99.2% of recruits having been spawned after the fishery had reopened (back-calculated median spawn date = May 5 ± 17 days SD), suggesting that the closure may be too early to adequately protect this population. Further, we present the first empirically derived estimates of pelagic larval duration for sea bass recruits settling in UK habitats, which showed a strong negative relationship with spawn date. Finally, we found significant differences in fish condition between the two estuaries, suggesting local variation in habitat quality. The results suggest that the timing of current fisheries closures may not be adequately protecting the spawners supplying these northernmost estuaries, which are likely to become increasingly important as sea bass distributions shift northward in our climate future.

Structural Changes in Liver Histology in Common Kilka <i>Clupeonella caspia</i> Svetovidov, 1941 under Anthropogenic Pressure

Histopathological changes are widely used as biomarkers of the health status of fish exposed to chemical compounds. Individuals of the common kilka Clupeonella caspia Svetovidov, 1941 caught from the Middle Caspian Sea exhibited significant changes in the cellular structure of the liver. The more common were signs of hyperemia: an edema of the liver parenchyma, vascular congestion, lympho-macrophage infiltration, small hemorrhages, and a narrowing of the bile duct lumen.

Influence of the dietary contribution of terrestrial insects to the condition factor of bleak Alburnus alburnus in a highly polluted lowland river.

Bleak Alburnus alburnus is a highly abundant but understudied fish species, and we know little about the trophic ecology of populations inhabiting rivers in central Europe. From an ecosystem perspective, this fish species is interesting as it is known to feed on surface insects, thereby linking the terrestrial with the aquatic habitat. In a previous study, we demonstrated that this flux is intensified, and dietary contribution of terrestrial insects is higher in fish inhabiting sections of the Spree River, Germany, that are polluted from iron oxides occurring from former lignite mining activities, and thus are characterized by lower abundances of aquatic insects. As terrestrial insects can be considered as food of lower quality (measured as long-chained polyunsaturated fatty acids, n-3 LC-PUFAs) compared to aquatic prey, it is reasonable to assume that the higher contribution of terrestrial insects is related to a lower body condition in fish. In this study, we explore the trophic ecology of riverine A. alburnus and their fitness consequences of feeding on terrestrial insects. We therefore modeled a terrestrial index from stable isotopes of hydrogen (δ2H) measured in the A. alburnus muscle tissue and compared individuals caught in locations upstream of a dam that were greatly influenced by iron oxides, with individuals caught in sections located downstream of a dam where passive remediation technologies are applied. The terrestrial index was significantly higher in A. alburnus caught in locations at high-iron concentrations, characterized by low abundances of aquatic prey, compared to A. alburnus caught in unpolluted habitats at low-iron concentrations. In contradiction to our hypothesis, the terrestrial index had no significant effect on the body condition of A. alburnus (measured as Fulton's condition factor K) in the sections downstream of the dam (i.e., at low-iron concentrations) and a significant positive, albeit weak, effect in sections upstream of the dam (i.e., at high-iron concentrations). However, the condition factor was generally lower in the high-iron section, potentially related to more direct effects of the iron oxide. We conclude that in A. alburnus, terrestrial insects can be considered as the less-favored food, unless the fish occur in environments where the aquatic food is of limited availability. Further research is needed to evaluate the direct and indirect effects, including the internal n-3 LC-PUFA synthesis as an adaption toward low-quality terrestrial prey on the fitness consequences of A. alburnus.

High spatial variability in a species-rich assemblage of diadromous fishes in Hong Kong, southern China.

China has experienced substantial coastal reclamation and damming of rivers. These changes have the potential to impact migrations of diadromous fishes between the sea and fresh waters, but the composition of these fishes and the impacts of barriers to their movement in China have received little attention. We inventoried the species composition and distribution of diadromous fishes, and the impacts of barriers on them, in the Hong Kong Special Administrative Region (HKSAR), southern China. Fish assemblages were surveyed using hand-nets, supplemented by cast-netting and single-pass snorkel surveys, in 24 small coastal streams across three regions. Surveys were undertaken on multiple occasions during the wet and dry seasons to account for the monsoonal tropical climate. Twenty-eight diadromous fishes were collected, mostly gobies, amounting to over half (53%) of the total richness of primary freshwater fishes; four additional species are known from literature records. Diadromous richness was 48% greater during the wet season, when all species were encountered. Richness varied substantially among streams, from a maximum of 17 (2 streams that were diversity hot spots) to none (3 streams). The most widespread diadromous fish was Glossogobius giuris (71% frequency of occurrence), followed by Mugil cephalus (58% occurrence) and Eleotris oxycephala (50% occurrence). The remaining 25 diadromous fishes occurred in fewer than half of the streams; 12 species were confined to a single stream and may be locally threatened. There were conspicuous spatial differences in diadromous assemblages across HKSAR, despite its limited extent (1114 km2), the proximity of the surveyed streams, and the broad geographic distribution of most species. Regional species assemblages were influenced by localized habitat characteristics, with a noticeable distinction between areas with and without large, fast-flowing, and highly oxygenated streams. The presence of in-stream barriers (weirs: 0.3-8.7 m high) did not affect spatial patterns in species assemblages, although, on average, diadromous richness was lower in weir-obstructed streams (4.0 vs. 6.9 species in unobstructed streams). In total, 18 species were confined to unobstructed streams or sections below weirs, whereas the remaining 10 species were recorded both above and below weirs. Only the mottled eel (Anguilla marmorata) and a goby (Stiphodon multisquamus) were able to ascend weirs over 2 m. Although at least 400 m of the lower course of each stream was sampled, diadromous fishes were confined to the first 300 m in 12 of the 13 weir-obstructed streams. Remarkably, the tally of 32 diadromous species in HKSAR exceeds the 19 known from mainland China, highlighting the need for further research on composition and conservation status of diadromous fishes.

Optimizing flow uniformity and velocity fields in aquaculture tanks by modifying water inlets and nozzles arrangement: A computational fluid dynamics study

Ensuring optimal conditions for fish, especially in terms of uniform velocity fields, is crucial for aquaculture systems to attain self-cleaning efficiency in rearing tanks and better fish behavior, which ultimately impacts their survival and growth. The current study presented a full-scale computational fluid dynamics (CFD) model of three types of circular, square and square arc angle tanks used in aquaculture farms to choose the most optimal tank based on the flow uniformity and velocity field. At the next step, the optimal arrangement of the inlet number, inlet location, inlet angle, as well as the number of nozzles on each inlet was reconfigured to create the most optimal tank. The simulations were done using the CFD software FLUENT distributed by the ANSYS Corporation. The software calculates velocities in the tanks by solving the Reynolds-averaged Navier-Stokes equations of continuity and momentum that govern the mean turbulent flow of water. The results illustrated circular and square arc angle tanks had significantly more uniform fluid velocity compared to the square tanks, which the square arc angle tank due to better flow velocity near the wall and space utilization was selected for further rearrangements. Additionally, the implementation of two entrance pipes near the corner of the two parallel walls with an entry angle of 0° in a square arc angle tank resulted in a more consistent water velocity. As the number of inlet nozzles increased to six, the water streamlines became more uniform, suggesting a more consistent water velocity throughout the tank. However, when the number of input nozzles increased to nine, the tension on the nozzle apertures were increased probably due to the decrease of distance between them. Findings of the present study concluded that two inlets in the corner with an entry angle of 0° and six nozzles on each inlet pipe could provide the optimum water velocity in the square arc angle tanks.

Cured or fresh? Between fish maturation trends in restaurants and food safety: The case of dry-aged rainbow trout

The application of dry aging on fish is increasing in restaurants worldwide. This process determines fluid loss, changes in muscle texture, and the development of a more concentrated flavour appreciated by consumers. Despite the growing popularity in the foodservice industry, there is a lack of data on potential risks and quality conditions of dry-aged fish. This study was aimed at assessing the safety for consumption of whole rainbow trout subjected to dry aging in a local restaurant (Turin, Italy). Quantitative microbiological analyses and detection of foodborne pathogens were performed on dorsal, ventral muscles, and skin samples at day 0, 3, 6, 10, and 14 of dry aging. Changes in water activity (aw), pH, colour, and biogenic amines in muscle were checked at each sampling point. Almost all the microbiological indicators were below the quantification limits in muscle until day 6 of dry aging, while higher but still acceptable loads were observed at day 10. At day 14, yeasts and moulds exceeded the acceptable level in one case (3.3 ± 0.4 log10 CFU/g) in ventral muscle and counts of Pseudomonas spp. (from 6.1 ± 0.8 to 6.4 ± 0.5 log10 CFU/g), total mesophilic (from 4.4 ± 0.3 to 5.3 ± 0.7 log10 CFU/g), and psychrophilic (from 5.4 ± 0.1 to 5.8 ± 0.3 log10 CFU/g) bacteria indicated the approaching of spoilage. Detection of Listeria monocytogenes and Staphylococcus aureus was always negative during the trials. Minimal changes of pH and colour were observed, while aw values followed a decreasing trend during dry aging. Putrescine was the only detectable amine, with a maximum concentration of 2.05 ± 0.02 mg/kg at day 14. In this study, dry-aged rainbow trout was safe for consumption and 10 days was the most appropriate curing time with 3 °C and 78% of relative humidity. Further studies at different environmental conditions and on other fish species are needed for a comprehensive risk assessment of this fast-growing practice in the restaurant sector.

Antagonistic and enzymatic activities of Bacillus species isolated from the fish gastrointestinal tract as potential probiotics use in Artemia culture.

Probiotics have been used successfully in aquaculture to enhance disease resistance, nutrition, and/or growth of cultured organisms. Six strains of Bacillus were isolated from the intestinal tracts of fish and recognised by conventional biochemical traits. The six isolated strains were Bacillus cereus and Bacillus subtilis using MALDI-TOF-MS technique. The probiotic properties of these Bacillus strains were studied. The tested bacillus strains exhibit antibacterial activity against the different pathogens. The strain S5 gave the important inhibition zones against most pathogens (20.5, 20.33, 23, and 21 mm against Vibrio alginolyticus, Vibrio parahaemolyticus, Staphylococcus aureus, and Salmonella typhimurium, respectively). According to our results, all Bacillus strains have extracellular components that can stop pathogenic bacteria from growing. The enzymatic characterization showed that the tested strains can produce several biotechnological enzymes such as α-glucosidase, naphtol-AS-BI-Phosphohydrolase, esterase lipase, acid phosphatase, alkaline phosphatase, amylase, lipase, caseinase, and lecithinase. All Bacillus strains were adhesive to polystyrene. The adding Bacillus strains to the Artemia culture exerted significantly greater effects on the survival of Artemia. The challenge test on Artemia culture showed that the protection against pathogenic Vibrio was improved. These findings allow us to recommend the examined strains as prospective probiotic options for the Artemia culture, which will be used as food additives to improve the culture conditions of crustacean larvae and marine fish.

Microbial Composition and Quality Changes in Whole Golden Pomfret (Trachinotus ovatus) During Refrigerated, Ice, and Vacuum-Packed Storage

ABSTRACT This study evaluated the quality and bacterial composition changes in whole golden pomfret under refrigeration, ice storage, and vacuum packaging at 4°C . Ice storage and vacuum packaging delayed sensory quality deterioration, limited spoilage bacteria proliferation, and slowed biogenic amines formation, total volatile base nitrogen accumlation, and ATP-related compounds degradation. In addition, Bacillus dominated fresh golden pomfret. Psychrobacter, Shewanella, and Acinetobacter were predominant in control and ice storage groups, while Shewanella and Aeromonas prevailed in the vacuum packaging group after storage. In conclusion, the best storage condition for whole golden pomfret fish is ice storage.

Toxic effects of antibiotic oxytetracycline in the fish, Cyprinus carpio using a multi-biomarker approach

Aim: The present study was designed to assess the toxic effect of oxytetracycline in the fish Cyprinus carpio using multi-biomarker approach following acute exposure. Methodology: The fish were exposed to sub-lethal concentration (80 mg l-1) of oxytetracycline for 96 hrs. Blood samples were collected 24, 48, 72 and 96 hrs after treatment. Biomarkers such as genotoxicity, biochemical parameters and alteration of the morphology of scales were used to assess the health status of fish after exposure to oxytetracycline. Genotoxicity was assessed using blood cell micronucleus assay. Results: Significant alterations in the nucleus and cytoplasm were noticed such as the aberrant nucleus and vacuolated cytoplasm which were time dependent in the treatment group compared to the control. Biochemical parameters such as blood glucose, total plasma protein, aspartate transaminase and creatinine levels were significantly altered in the oxytetracycline exposed groups. The examination of body scales of treated fish revealed significant alterations such as uprooted and damaged lepidonts and dispersed chromatophores. Interpretation: The data of the present study indicates that oxytetracycline is toxic to fish at sub-lethal concentration. Key words: Antibiotics, Biomarkers, Cyprinus carpio, Genotoxicity, Oxytetracycline, Scale

Innovative Solutions to Environmental Challenges: Exploring Fishermen's Perspectives on Technology-driven Conservation Efforts in Noveleta, Cavite

This phenomenological study explores the viewpoints of fishermen in Noveleta, Cavite, on technology-based conservation initiatives and their effects on local marine ecosystems and fishing methods. Using purposive sampling, seven participants offered valuable insights into the present condition of marine life, the implementation of cutting-edge solutions, and the impact of these technologies on their means of living. The study revealed several themes: The challenges of modern fishing conditions, including stricter laws, and the consequences of environmental changes, such as pollution and habitat damage. Fishermen also discussed how government rules impacted them and how new technologies like GPS and fish finders brought new challenges even as productivity rose. Furthermore, the discussion underscored significant concerns such as the necessity for efficient marine conservation, the impact of infrastructure developments on local communities compared to traditional practices, and the economic viability amidst shifting circumstances. This study highlights the complex connection between policy, technology, and traditional fishing methods, highlighting the importance of inclusive and sustainable approaches to conservation.

Seasonal Effects on Health Status and Parasitological Traits of an Invasive Minnow in Iberian Waters.

Biological invasions are of special conservation concern in the Iberian Peninsula and other regions with high levels of endemism. Environmental variability, such as the seasonal fluctuations of Mediterranean streams, is a key factor that affects the spread of aquatic species in novel habitats. Fish parasites have a great potential to reflect such changes in the habitat features of freshwater ecosystems. The aim of this study consisted of seasonally analysing the health status and parasitological traits of non-native fish in Iberian waters. In particular, a strongly invasive population of Languedoc minnow Phoxinus septimaniae (leuciscid species native to south-east France) was assessed in Tordera Stream (north-eastern Iberian Peninsula, Mediterranean conditions). Fish were sampled in April, July, and October 2023 by electrofishing. Health status (external/internal organs) was significantly better in autumn (HAI = 28.8) than spring (HAI = 35.6). Life-cycle complexity was higher in spring (LCI = 1.98), whereas parasite abundance and Shannon diversity were significantly lower in autumn (TA = 19.6 and H' = 2.15, respectively). In October (more 'benign' environmental conditions in Iberian streams), minnows could display elevated foraging activity, with fish increasing their health condition and level of parasite resistance/tolerance. Overall results showed a particular seasonal profile of health and parasite infra-communities that allow this minnow species to thrive under highly fluctuating habitat conditions. This information could help environmental managers to control non-native fish in Mediterranean streams.

Growth Patterns, Status of Well-Being and Trend Analysis of Three Commercially Important Clupeid Species from Selangor Landing Port

Length-weight relationships (LWRs) and condition factors are vital to quickly understanding the fitness and well-being of fish. There is currently no available evidence on LWRs, condition factors and landing trend for these three species and an absence of this information will result in improper management and monitoring of fish species. In this study, the growth patterns, status of well-being and trend analysis of commercially important clupeid species from the west coast of Peninsular Malaysia were studied. Sardinella lemuru, Amblygaster sirm and Nematalosa japonica were selected due to high commercial value and conservation status. S. lemuru was specifically categorized as near threatened by the IUCN with decreasing global populations. Total length (cm) and body weight (g) of S. lemuru, A. sirm and N. japonica were accounted for in this study, which was obtained from the wet market in the west coast of Peninsular Malaysia. The relationships between length and, weight and, condition factors (Fulton’s, KF; relative condition factor, Kn; Allometric) were assessed. The allometric equation; W = aLb was used to evaluate the length-weight relationships while KF = 100W/Lb and Kn = W/aLb were used to estimate fish condition factor. ARIMA (1,1,1) and ARIMA (0,1,0) models were utilised to forecast the fish landing pattern until 2030. The results showed that the coefficient of determination R2 values varied between 0.263 (Sardinella lemuru), 0.5187 (Amblygaster sirm) and 0.8443 (Nematalosa japonica) and b values ranged from 0.0959 to 2.1005. From this, all three fish species have shown a negative allometric growth pattern b<3, reflecting a relatively slow growth rate and size of fish. No positive allometry was detected for any of the sampled fish species. A low value of relative condition factor (Kn < 1) suggests that all the fish species in this study have poor physical characteristics due to inadequate food resources, and unsuitable habitats for expansion of the fish population. Prediction based on Autoregressive Integrated Moving Average (ARIMA) model showed that N. japonica would increase gradually in the coming years, while S. lemuru would remain constant. This study contributes to the knowledge base for S. lemuru, A. sirm and N. japonica in the west coast of Peninsular Malaysia, and is crucial in terms of understanding the ecology of the habitat for supporting conservation strategies, and the restoration and management of these species in future.

Therapeutic effects of white poplar (Populus alba) leave extract on hepatorenal, stress, and antioxidant-immune parameters of Oreochromis niloticus challenged with Aeromonas veronii

Herbal plants have gained enormous interest due to their immune, antioxidant, and antibacterial activities. The present study proposed that white poplar (Populus alba) leave extract (WPE) might provide a promising alternative to traditional antibiotics to treat Aeromonas veronii infection in Nile tilapia (Oreochromis niloticus). WPE showed an in vitro antibacterial activity [22 ± 0.45 mm inhibition zone, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 60 µg/mL] against A. veronii. For the in-vivo study, a factorial (2 × 2) design was used to investigate the therapeutic effects of WPE on the antioxidant/immune status and blood biochemical parameters of Nile tilapia challenged with A. veronii. One-hundred sixty fish (33 ± 1.5 g) were assigned into four experimental groups, each with four replicates (4 glass tanks/group, 40 fish/group, 10 fish/tank) for 10 days. In the first (1st) and 2nd groups, 0 and 1.5 mg/L WPE were applied in tank water, respectively, without fish being challenged. In the 3rd and 4th groups, 0 and 1.5 mg/L WPE were applied in tank water, respectively, with fish intraperitoneal inoculated with 0.2 mL of A. veronii (0.5 × 107 CFU). Aeromonas veronii infection significantly diminished the survivability, hepatic catalase, lysozyme activity, nitric oxide, immunoglobulin M, phagocytic %, total protein, albumin, and globulin. Moreover, a significant rise in the hepatic malondialdehyde, serum hepatorenal function indicators, cortisol, and glucose levels were consequences of A. veronii challenge. Interestingly, the interaction between bacterial challenge and WPE application increased the survivability, antioxidant activity, and immune responses and reduced ALT levels of fish treated with WPE during the bacterial challenge. The serum creatinine, cortisol, and glucose levels were decreased in fish treated with WPE during the infection but still higher than in the non-infected fish either treated or not treated with WPE. In conclusion, WPE (1.5 mg/L) can be used as an antibacterial substance in fish farming to alleviate the detrimental impacts of A. veronii infection by enhancing the antioxidant/immune status of the infected fish. These outcomes could help reduce antibiotic usage in fish farms, which is conducive to the sustainable development of aquaculture.