Death Of Fish Research Articles

Identification and level of ectoparasite intensity in goldfish (Carassius auratus) at fishery product inspection and certification center fish seed center

Diseases and parasites that attack the fish body are often encountered in ornamental fish cultivation, so they can reduce the quality of the fish and cause fish death. Ectoparasites are parasites found outside the fish body. This study aimed to determine the type and intensity level of ectoparasite distribution in goldfish (Carassius auratus) cultivated at the Fishery Product Inspection and Certification Production Center (PPISHP) Fish Seed Center (BBI) Ciganjur, South Jakarta. A location survey and random sampling from three different rearing ponds were used. The goldfish samples obtained were 60 fish from three ponds in BBI Ciganjur. The results showed that the highest level of intensity of the Argulus sp. parasite was found in pond 2, the highest level of intensity of the Trichodina sp. parasite was found in pool 1, and the highest level of Lernea sp. parasite intensity was found in pools 1 and 3. The average infection level of each parasite showed that the intensity was relatively low.

Optimization of iron flocculation for enrichment of CyHV-2 in aquaculture water

Cyprinid herpesvirus 2 (CyHV-2) is an important infectious virus endangering the farmed Carassius species industry. The enrichment and identification of CyHV-2 in the water is a vital means of early warning diagnostics, which is helpful to aquatic diseases prevention and control. In this study, we employed and optimized iron flocculation to enrich the concentrations of CyHV-2 in aquaculture water. Different Fe3+ concentrations (0.5, 1.0, and 10.0 mg/L), various membrane filters (mixed cellulose ester, glass fiber, nylon microporous filter membrane), different elution buffers containing reductants (ascorbate, citrate, DL-malate, and their combinations with EDTA or TE buffer) were compared to check the recovery yield of CyHV-2. Viral genome quantitation was determined using quantitative real-time PCR. The results showed that Fe3+ concentration of 1.0 mg/L, the glass fiber and citrate-TE were determined to have high efficiency and stable recovery yield. To evaluate infectious CyHV-2 viral titres, crucian carps (Carassius auratus) were intraperitoneally injected with CyHV-2. The mortality rate was 100 % at 9 days postinoculation (dpi) with the 96.7 % detection of CyHV-2 in the pooled tissues. The histopathological phenotype showed necrotic cell death in the liver, spleen and kidney. The CyHV-2 genome was ranging from 101.1 to 107.5 copies/μl in the deceased fish, and 101.4 to 103.0 copies/μl in the feeding water at various stages from latent infection to onset of disease. The field samples from Huzhou, Zhejiang Province on June 4th and 7th had higher detection rates, 87.5 % and 100 % respectively, corresponding to higher CyHV-2 detected in the aquaculture water. CyHV-2 viral load in cultured waters tends to increase prior to fish death, which provides a new indicator for the prediction of fish diseases. In summary, we have established a unified operational standard for enrichment of CyHV-2 in the aqueous environment by iron flocculation.

Mining disaster in Brumadinho (Brazil): Social vulnerability from the perspective of the fisherman community

On January 25, 2019, the state of Minas Gerais (MG) in Brazil witnessed yet another disaster involving the collapse of a mining tailings dam. The disaster occurred in the municipality of Brumadinho, belonging to VALE S.A. One of the activities most affected by the disaster was fishing, which suffered from the immediate death of fish, limitations on the use of water resources and uncertainty about the quality of fish for consumption. In addition, this environmental disaster may have caused socio-environmental and economic impacts, severely damaging the region's riverside community and professional artisanal fishermen. This study was carried out with the fishing community and sought to assess their social vulnerability. In order to characterize the activity and identify possible damage, semi-structured interviews were conducted in May 2022. To analyze the qualitative data, the “RAPFISH” method was adapted, considering the following dimensions: 1- social, 2- perception of environmental risk and health, 3- economic, 4- management and technology, and 5- professional organization and governance. The results showed that the fishing communities have managed to maintain and improve their conditions in some of the dimensions considered, but still present situations of social vulnerability. They indicated that fishing is fundamental to family livelihoods and continues to be practiced regardless of the community's perception of risk. However, raising awareness about fish quality, marketing and consumption after the disaster requires more information and monitoring. Our approach was able to show that, among the five components, the social, environmental and economic dimensions are priorities for planning future actions.

Study on the effect of aeration system on the mass transfer performance of supersaturated total dissolved gas

ABSTRACT The release of supersaturated total dissolved gas (STDG) from dams has been linked to the development of gas bubble disease, which can ultimately result in the death of fish. In order to minimize the impact of STDG on aquatic ecology, the effect of aeration on mass transfer at the air–liquid interface is taken into account. This paper selects four commonly used aerators to carry out indoor aeration tower experiments under different aeration conditions (aeration aperture, aeration water depth, and aeration volume), exploring aerators that can efficiently promote STDG release. The results indicated that the diaphragm aerator was found to have the greatest effect on STDG release, followed by corundum and spin mix aerator. In contrast, a pinhole aerator was found to have the least beneficial impact on STDG release. The increase in the release coefficient for the diaphragm aerator in comparison to the pinhole aerator is 32%. A prediction model for the aeration system was developed based on the mass transfer mechanism at the gas–liquid interface. The parameters in the model were determined using experimental data, which effectively improved the model's prediction accuracy. The findings of this study may serve as a reference point for the selection of the most suitable aerator in the actual engineering of STDG mitigation by aeration technology.

Assessment of seasonal variations of some heavy metals in water samples collected from Gwaigwaye, Maska and Zobe dams

Water pollution can Damage Aquatic Ecosystems, leading to Death of Fish, plants and other Aquatic organism, which in turn can Disrupt the Entire Food chains. This study was conducted to Determine the Concentrations of Some Heavy metals in water samples obtained from Gwaigwaye, Maska and Zobe Dams in Dry and wet Seasons. The Dams provides water for Drinking, Fishing, Farming and other Agricultural Activities to the Neighbouring Communities. In this study water samples collected from Gwaigwaye, Maska and Zobe Dams in Dry and wet Seasons were Analyzed for Some Heavy metals namely, Cadmium, Cobalt, Copper, Nickel, lead and zinc. After Samples Digestion, microwave plasma atomic emission spectroscopy(MPAES) was used for the Determination of the Metal concentrations and their Levels were compared with permissible limits set by local and international standard regulatory Authorities. From the result of the Analysis, the Concentrations of the Heavy metals in Dry season in mg/L ranged as follows. 0.00±0.00 to 0.03±0.00 mg/L for Cd, 0.02±0.00 to 0.084±0.002 mg/L for Co, 0.057±0.003to 0.186±0.003 mg/L for Cu, 0.03±0.00 to 0.19±0.005 mg/L for Ni, 0.00±0.00 to 0.01±0.00 mg/L for Pb and 0.06±0.02-0.193±0.003 mg/L for Zinc. Similarly, the Concentrations of metals in wet season in(mg/L) ranged as follows, 0.00±0.00 to 0.027±0.002 for Cd, 0.02±0.002 to 0.071±0.002 for Co, 0.051±0.003 to 0.103±0.014 for Cu, 0.029±0.003 to 0.12±0.013 for Ni, 0.00±0.00 to 0.00±0.00 for pb and 0.057±0.002 to 0.160±0.003 for Zinc. The Concentrations level of Cd, Co and Ni in water samples from Maska, Gwaigwaye and Zobe Dams in dry season were above the permissible set by WHO/SON. However, Cu, Pb and Zn were within the permissible limit of WHO and SON in all the Dams in dry and wet seasons. The Result of Statistical Analysis indicated no Significant Difference between the Metals in all the Dams in both Dry and Wet seasons as p values were greater than 0.05( p >0.05).

The effect of an organomineral chelate complex on the amylolytic activity of intestinal enzymes of some fish species

To date, there is a large amount of information regarding the effect of heavy metals on the hydrolases of the digestive tract. It has been established that even biogenic metals in high concentrations can have a toxic effect. The assessment of the activity of digestive hydrolases is relevant, since a change in their activity has a direct effect on the effectiveness of assimilation of food. Amylolytic hydrolases help to provide the body with carbohydrates (along with fats) – the main sources of energy for fish. A decrease in the intake of carbohydrates will lead to a violation of metabolic processes and, as a result, underdevelopment and death of fish. The aim of the study was to determine the effect of an organomineral chelate complex on the amylolytic activity of intestinal enzymes of some fish species. The research was conducted at the Department of Biochemistry and Physiology of the St. Petersburg State University of Veterinary Medicine and on the basis of two fisheries in the Leningrad Region. The fish of the experimental groups (n = 10) were given an additive for 30 days, the data were compared with the control (n = 10). The drug was given together with the feed once a day, at a concentration of 0.5 g / kg (feed weight). Fingerlings (0+) of 3 species of freshwater bony fish were used as research objects: Carassius auratus (n=20), Cyprinus carpio (n=20), Oncorhynchus mykiss (n=20). Amylolytic activity was determined in the total homogenets of the intestinal mucosa of fish. The activity was assessed by the increase in hexoses by the Nelson method in the modification of Ugolev, Jesuitova. The detection was carried out on a photoelectric KKK-3 photometer. Based on the studies obtained, it can be concluded that the use of an organomineral chelate complex in the studied dosage (previously worked out in conditions of determining acute and chronic toxicity for fish) does not have a negative effect on the amylolytic activity of intestinal enzymes. There was no significant decrease in amylolytic activity in all experimental groups. Based on this, it is possible to recommend the use of a chelate complex for fish in industrial aquaculture.

A Theoretical Comparison of Alternative Male Mating Strategies in Cephalopods and Fishes.

We used computer simulations of growth, mating and death of cephalopods and fishes to explore the effect of different life-history strategies on the relative prevalence of alternative male mating strategies. Specifically, we investigated the consequences of single or multiple matings per lifetime, mating strategy switching, cannibalism, resource stochasticity, and altruism towards relatives. We found that a combination of single (semelparous) matings, cannibalism and an absence of mating strategy changes in one lifetime led to a more strictly partitioned parameter space, with a reduced region where the two mating strategies co-exist in similar numbers. Explicitly including Hamilton's rule in simulations of the social system of a Cichlid led to an increase of dominant males, at the expense of both sneakers and dwarf males ("super-sneakers"). Our predictions provide general bounds on the viable ratios of alternative male mating strategies with different life-histories, and under possibly rapidly changing ecological situations.

Characterization and inter-strain variability in ichthyotoxicity of Heterocapsa ovata (Peridiniales, Dinophyceae) from temperate waters of South Australia

IntroductionHarmful algal bloom (HAB)-forming species and populations exhibit substantial intraspecific functional trait variation, which can confer eco-evolutionary advantages. Phenotypic variability among populations can buffer the immediate detrimental effects of environmental fluctuations, with more diverse populations expected to survive changing conditions more efficiently than their uniform counterparts.MethodsIn February 2014, a mixed fish-killing dinoflagellate bloom occurred in the temperate waters of Coffin Bay, South Australia, causing the death of oysters and fish in the area. The bloom was dominated by Karenia mikimotoi and a cryptic species of Heterocapsa. Twenty-one monoclonal Heterocapsa isolates were established from the site and identified as H. ovata using microscopy and universal ribosomal markers (ITS/5.8S and LSU D1/D3 rDNA regions; SSU and cob were used for amplicon sequencing). These isolates were tested for ichthyotoxicity using a bioassay based on cells from the gills of rainbow trout (Oncorhynchus mykiss). Culture fraction preparations (whole cells, supernatant, and lysed cells) were analyzed to determine ichthyotoxicity levels.ResultsThe highest ichthyotoxicity was observed in lysed cells, with surprisingly high inter-strain variability. This suggests that different strains of H. ovata have varying levels of toxicity.DiscussionResults from this study expand our understanding of the adaptive strategies of HAB species and enable predictions of future population dynamics under changing climatic conditions. The substantial phenotypic variability among H. ovatastrains highlights the potential for diverse responses to environmental stressors, underscoring the importance of considering intraspecific variation in ecological and evolutionary studies of HABs.

Investigation of small-scale farming status of Tire track eel (Mastacembelus favus) in the Mekong Delta, Vietnam

Tire track eel (Mastacembelus favus) is an economically important freshwater fish in the Mekong Delta. However, there is a lack of academic information about the current farming status, feed, and feeding related to this species in the region. Therefore, a field survey of small scale farming of tire track eel was conducted in An Giang, Dong Thap, Hau Giang and Kien Giang provinces of Vietnam. The objective of the survey was to determine the current farming practices information on households, especially the feed and feeding status of tire track eel in order to improve and develop a suitable feed for this fish in the future. The results showed that most of the small-scale farmers cultured fish in earthen ponds with or without plastic liners. Tire track eels were fed with feeds of other species and typically fed 3 - 5 times/d during the fingerling stage, and twice per day during the grow-out period. In terms of feed ingredients, crude protein contents in the feeds were 39.5 - 45.5% while crude lipid contents were 7.7 - 12.7%. Feed conversion ratios of tire track eels were 2 - 5. The farming periods of fish were 11.8 - 14 months when the fish reached the harvesting sizes of 318.2 - 421.4 g/fish, with the survival rates of 40 - 80%. It took 2.5 months to cultivate the fingerling stage (around 3 g/fish) from the fry with the survival rate of 55.7%. It was reported that this species was raised with a simple technique and got less illness compared to other fish species. However, the main reason of fish deaths during farming period related to management factors such as poor water quality due to decomposition of uneaten feed in water or lacks of dissolved oxygen due to high stocking density or power supply failures.

Qualities and Quantities of Poultry Litter Biochar Characterization and Investigation

Excessive land application of poultry litter (PL) may lead to surface runoff of nitrogen (N) and phosphorus (P), which cause eutrophication, fish death, and water pollution that ultimately have negative effects on humans and animals. Increases in poultry production in the Delmarva Peninsula underscore the need for more efficient, cost-effective, and sustainable disposal technologies for processing PL instead of direct land application. The pyrolysis conversion process can potentially produce nutrient-rich poultry litter biochar (PLB), while the pyrolysis process can change the N and P to a more stable component, thus reducing its runoff. Pyrolysis also kills off any microorganisms that would otherwise trigger negative environmental health effects. This study is to apply an integrated method and investigate the effect of pyrolysis temperature (300 °C, 500 °C), poultry litter source (different feedstock composition), and bedding material mixture (10% pine shavings) on PLB qualities and quantities. Proximate and ultimate analysis showed PL sources and bedding material addition influenced the physicochemical properties of feedstock. The SEM and BET surface results indicate that pyrolysis temperature had a significant effect on changing the PLB morphology and structure, as well as the pH value (7.78 at 300 °C vs. 8.78 at 500 °C), extractable phosphorus (P) (18.73 ppm at 300 °C vs. 11.72 ppm at 500 °C), sulfur (S) (363 ppm at 300 °C vs. 344 ppm at 500 °C), and production yield of PLBs (47.65% at 300 °C vs. 60.62% at 500 °C). The results further suggest that adding a bedding material mixture (10% pine shavings) to PLs improved qualities by reducing the content of extractable P and S, as well as pH values of PLBs. This study also found the increment in both the pore volume and the area of Bethel Farm was higher than that of Sun Farm. Characterization and investigation of qualities and quantities of PLB using the integrated framework suggest that PL from Bethel Farm could produce better-quality PLB at a higher pyrolysis temperature and bedding material mixture to control N and P runoff problems.

An Integrated Smart Pond Water Quality Monitoring and Fish Farming Recommendation Aquabot System.

The integration of cutting-edge technologies such as the Internet of Things (IoT), robotics, and machine learning (ML) has the potential to significantly enhance the productivity and profitability of traditional fish farming. Farmers using traditional fish farming methods incur enormous economic costs owing to labor-intensive schedule monitoring and care, illnesses, and sudden fish deaths. Another ongoing issue is automated fish species recommendation based on water quality. On the one hand, the effective monitoring of abrupt changes in water quality may minimize the daily operating costs and boost fish productivity, while an accurate automatic fish recommender may aid the farmer in selecting profitable fish species for farming. In this paper, we present AquaBot, an IoT-based system that can automatically collect, monitor, and evaluate the water quality and recommend appropriate fish to farm depending on the values of various water quality indicators. A mobile robot has been designed to collect parameter values such as the pH, temperature, and turbidity from all around the pond. To facilitate monitoring, we have developed web and mobile interfaces. For the analysis and recommendation of suitable fish based on water quality, we have trained and tested several ML algorithms, such as the proposed custom ensemble model, random forest (RF), support vector machine (SVM), decision tree (DT), K-nearest neighbor (KNN), logistic regression (LR), bagging, boosting, and stacking, on a real-time pond water dataset. The dataset has been preprocessed with feature scaling and dataset balancing. We have evaluated the algorithms based on several performance metrics. In our experiment, our proposed ensemble model has delivered the best result, with 94% accuracy, 94% precision, 94% recall, a 94% F1-score, 93% MCC, and the best AUC score for multi-class classification. Finally, we have deployed the best-performing model in a web interface to provide cultivators with recommendations for suitable fish farming. Our proposed system is projected to not only boost production and save money but also reduce the time and intensity of the producer's manual labor.

Ultrasonic control of aquatic macrophytes in reservoirs: An integrated review

The excessive proliferation of cyanobacteria and aquatic macrophytes in water reservoirs has been a concern for governments, energy companies managing hydroelectric and thermal power plants, and local populations. These aquatic organisms, when overabundant, negatively impact the management of water for public supply and energy generation, obstructing intake systems and damaging water treatment stations. Ultrasound emerges as a potential technique for controlling these organisms. The aim of this study was to perform an integrative review by selecting articles published between 2020 and 2024, focusing on the efficacy and ecological implications of ultrasonic control on these aquatic populations. The methodology involved searching scientific databases, selecting 14 articles out of a total of 42, based on their relevance to the theme of ultrasonic control and its practical applicability. The results indicate that ultrasonic frequencies of 20 kHz collapsed gas vacuoles in these aquatic organisms within 40 seconds of exposure, demonstrating the potential application of this technique in controlling these organisms, although it is necessary to adjust the intensity according to the specific environmental conditions of the reservoir and the biology of the target organisms. However, exposure to ultrasound can release toxins, affect non-target organisms, and alter the aquatic community structure, resulting in negative impacts such as hypoxia and fish death. It highlights the need to adopt an adaptive model to adjust ultrasound parameters and integrate them with other management practices. The study emphasizes the importance of conducting laboratory-scale tests and continuous monitoring to optimize efficacy and minimize environmental risks. Future development of more efficient and less invasive ultrasonic transducers is also recommended, as well as interdisciplinary collaboration to promote more sustainable reservoir management.

Novel insights into immune stress markers associated with myxosporeans gill infection in Nile tilapia (molecular and immunohistochemical studies).

Nile tilapia (Oreochromis niloticus) is valued in aquaculture because of its quick development and ability to thrive in various environments. Myxosporeans are among the fish parasites that affect fish productivity, as they impact fish growth and reproduction, resulting in large fish deaths in farms and hatcheries. This study has been focused on morpho-molecular identification for the myxosporean parasites infecting Nile tilapia from three governorates in Egypt and assessment of gene expression of different cytokines (Interleukin-1βeta (IL-1β), major histocompatibility complex class II (MHC-II), and clusters of differentiation 4 (CD-4) and 8 (CD-8)) in tissues. Additionally, this work aimed to correlate the developed histopathological alterations and inflammatory reactions in gills with immunohistochemical expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α). Finally, the infected fish's cortisol levels and blood glucose were assessed. Results of BLAST sequence analysis of the 18S rRNA for the collected protozoans confirmed Myxobolus agolus, M. brachysporus, M. tilapiae, and Henneguya species. The molecular characterization of the immunological status of gills revealed marked upregulation of different inflammatory cytokines in the gills of infected fish. There was a significantly increased serum cortisol and glucose level in infected fish compared with control, non-infected ones. Severe histopathological alterations were observed in the infected fish gills, associated with increased expression of iNOS and TNF-α and related to myxosporean infection. The present study provides new insights into oxidative stress biomarkers in Nile tilapia infected with Myxosporeans and elucidates the gill's immune status changes as a portal of entry for protozoa that contribute to tissue damage.

Implementation of Naïve Bayes Method Diagnosing Diseases Nile Tilapia

The Nile tilapia, also known as Oreochromis niloticus, was a freshwater fish species first produced in East Africa in 1969. It became a popular aquaculture fish in freshwater ponds across Indonesia. Besides its delicious taste, the Nile tilapia is rich in nutrients essential for human health. However, cultivating Nile tilapia was challenging due to frequent bacterial diseases. These diseases often led to mass fish deaths, causing financial losses, especially for new fish farmers. The rapid spread of diseases emphasized the need for prompt intervention to prevent further losses. Farmers needed adequate knowledge about Nile tilapia diseases, but often struggled to absorb information provided by the government. Hence, the presence of experts or veterinarians was crucial in assisting farmers to address these issues. Farmers of Nile tilapia sought assistance from experts or veterinarians, but this was not easy. It involved substantial costs and time, while quick intervention was necessary to mitigate losses. The solution proposed was the development of an expert system for diagnosing and treating Nile tilapia diseases. Thus, an expert system was built to assist fish farmers in identifying fish diseases and their treatments by implementing the naïve Bayes method. The expert system transferred human knowledge to computers, enabling them to solve problems like experts, thereby making expert knowledge accessible to non-experts. Naïve Bayes was implemented to determine the highest probability based on input symptoms. This research used five test data samples to apply the naïve Bayes method to diagnose Nile tilapia diseases, resulting in an accuracy rate of 80%. Therefore, the implementation of naïve Bayes in diagnosing Nile tilapia diseases is considered reasonably effective.

DETERMINANTS OF THE MORTALITY OF PATIN FISH IN TEMERLOH, PAHANG, MALAYSIA

This study explores the factors influencing Patin fish mortality in Malaysia's expanding aquaculture industry, which is crucial for meeting the rising global demand for fish and seafood. Analysing data from 135 fish farmers through SPSS Software, it finds significant correlations between mortality rates and variables like fish species, time until sale, and fish quantity per cage. At the same time, factors such as partnership numbers and feeding frequency have minimal impact. These results highlight the critical role of water quality management in fish health and production costs. The findings are vital for developing strategies to improve fish farming and water quality control in Malaysia, addressing the need to consider various factors to reduce fish mortality. Despite the significance of certain variables, the low adjusted R-squared value points to other yet unidentified factors affecting fish deaths, suggesting ongoing data collection and model refinement for stakeholders. This research contributes to understanding aquaculture costs and fish health, informing theories such as Interactive Governance Theory, Stress Response Theory, and Disease Ecology Theory and underscoring the importance of comprehensive strategies for sustainable aquaculture practices.

Pathological caudal skeleton of an ichthyodectiform fish from the Upper Cretaceous Niobrara Formation of western Kansas, USA.

A series of 12 contiguous caudal vertebrae of an ichthyodectiform fish from the Smoky Hill Chalk Member of the Niobrara Formation is described. The vertebral centra exhibit extensive overgrowth of pathological bone and there is additional pathological bone within the centra and intervertebral spaces, which together resulted in the coossification of most centra. The extent of the pathology is greatest on preural vertebrae 1-3 and decreases anteriorly, which suggests that the pathology began posteriorly and progressed anteriorly. In addition to the pathological overgrowth on bones, the specimen preserves features interpreted as calcified and/or ossified soft tissues associated with the neural and haemal canals. The pathologies are unlike previously described examples of bony pathologies in fish, and it is suggested that they resulted from combined bacterial and fungal infections. As the pathologies developed, they would have adversely impacted the fish's swimming and feeding abilities, and presumably eventually led to the fish's death.

The Effects of Algal Blooms on Oxygen Levels in Lakes Babati and Eyasi, Tanzania

Globally aquatic ecosystems are reportedly overwhelmed by algal blooms due to excessive deposition of nutrients which ultimately cause hypoxia, leading to massive fish death. This study aimed at assessing the relationship between algae contents and dissolved oxygen (DO) in Lake Babati which is threatened by anthropogenic activities, whereas Lake Eyasi was used as a control. Algae contents (chlorophyll a), DO and surface water temperature were measured using standard methods. Results revealed that the mean algae content was significantly higher (4.47±0.88 mg/L) in Lake Babati than in Lake Eyasi (1.6±0.45 mg/L) (P < 0.05) and was beyond the standard permissible levels for domestic water supply and healthy ecosystem. Conversely, DO was significantly lower in Lake Babati than in Lake Eyasi (P < 0.05). There was no significant difference in water temperature in the two lakes (P > 0.05). Furthermore, there was an inverse relationship between algae content and DO in Lakes Eyasi and Babati (r = -0.88 and r = -0.30, respectively) suggesting that algal bloom is partly responsible for lowering DO. Responsible authorities are advised to enforce management policies and regulations to control unsustainable activities around these lakes that contribute to nutrient loading resulting into overgrowth of algae.

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.

The complete genome sequence of the protogynous hermaphrodite North American annual killifish Millerichthys robustus (Rivulidae, Cyprinodontiformes).

The Mexican Rivulus, Millerichthys robustus, is an enigmatic species of seasonal killifish endemic of the Southeast Mexico that has changed paradigms on the evolution of annualism in killifishes. This species survives in ephemeral environments that experience a period of seasonal drought that causes the death of all adult fish. However, populations persist due to their drought-resistant embryos capable of arresting their development in diapause until the next the rainy season. Millerichthys evolved unique characteristics within annual killifishes as a functional sequential hermaphroditism, in which females change to males (protogynous) under perceived conditions of mate competition. Also, M. robustus express different color phenotypes in both sexes: five-color phenotypes continuously distributed in various perceptual units between yellow and red in males, and different number of ocelli disposed in caudal peduncle in females. The phylogenetic relationships of M. robustus revealed that it is a sister clade to two non-annual species found exclusively in Cuba (Rivulus cylindraceus and Rivulus berovidesi), indicating that the annual life cycle, through the acquisition of embryonic diapause, has evolved independently in this species. Here, we present the complete genome sequences for the North American annual killifish Millerichthys robustus. The raw data and assembled genome are available in GeneBank.

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.