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There have been few documented extinctions of fished species, but many bioeconomic models predict that open‐access incentives make extinction possible. Open‐access multi‐species fisheries can cause species' extinction if other, faster‐growing species maintain profits at fatal effort levels. Even target species can be profitably harvested to extinction if their prices rise sufficiently as they are depleted. Here, we explore interactions between these potential extinction mechanisms by modelling an open‐access multi‐species fishery with one or multiple fleets exploiting two species, each with different growth rates, ex‐vessel prices, and price dynamics. Increases in the strong stock's (the stock with higher productivity relative to fishing susceptibility) price as it is depleted increase the range of conditions under which the weak stock can be driven extinct and shrinks the range of bioeconomic parameters in which both species can coexist under open‐access. Catch hyperstability – whereby species become easier to catch as they are depleted – makes the weak stock weaker as it is depleted and further narrows the scope for coexistence. Fleet diversity in targeting ability can prevent weak stock extinction, as competition or switching balances species abundances. With few documented global fished‐species extinctions, our results raise important questions, which we discuss. Is the apparent lack of extinctions largely due to management? Are more species in lightly‐managed fisheries threatened with extinction than previously acknowledged? Have more extinctions than we realize already happened in data‐ and management‐poor fisheries? Or have fishes' high fecundity and the oceans' vastness provided protection against extinction that is uncaptured by existing theoretical models? [ABSTRACT FROM AUTHOR]

Kurniasih S, Sunarto, Setyono P. 2024. Implementation of Floating Net Cages (FNC) cultivation and risks to sustainable fisheries in the Gajah Mungkur Reservoir, Wonogiri, Central Java, Indonesia. Nusantara Bioscience 16: 228-236. Floating Net Cages (FNC) is an effort to intensify fish production in the Gajah Mungkur Reservoir, Wonogiri, Central Java, Indonesia. The increase in the number of FNC is directly proportional to the production of FNC fish, so it can decrease water quality. The study aims to look into how FNC affects the water quality in the FNC area of the Gajah Mungkur Reservoir and how the threat of FNC water conditions affects the long-term viability of FNC aquaculture in the Gajah Mungkur Reservoir. The data collection technique was purposive sampling, which was analyzed using quality standard evaluation and plankton community structure analysis. The research results show that the water quality parameters measured are based on standards for fisheries activities, except for the COD and BOD parameters. Most plankton found are from the Bacillariophyceae class. The FNC area in the Gajah Mungkur Reservoir includes eutrophic waters with a low diversity and moderate pollution. The evenness exceeds 6 and the C value is less than 0.5. The saprobic indexes for the pollution level in the FNC area's waters is classified as very low to low, with few organic and inorganic compounds in the Oligo/β-Mesosaprobik to β- mesosaprobik phase. Six families of fish have been found in the Gajah Mungkur Reservoir, namely Cyprinidae, Pangasiidae, Eleotrididae, Cichlidae, Channidae, and Bagridae. Social conflict, mass fish deaths, and increasing water pollution are risks to floating net cages cultivation. Commitment, implementation, and supervision are crucial in executing FNC management through an ecosystem approach, ensuring the sustainability of FNC aquaculture and preserving food security. [ABSTRACT FROM AUTHOR]

Several previous studies of marine fish stocks have demonstrated time‐varying recruitment productivity and indicated that including time‐varying parameters can track process variation in recruitment. Few studies have synthesized signal‐to‐noise ratios and underlying reasons for time‐variation across stocks and regions. Using Peterman's productivity method (PPM), we provide a broad synthesis of time‐varying density‐independent productivity in 84 stocks across five regions of the United States. Of all stocks investigated, 50 were found to have time‐varying productivity, challenging assumptions on the stationarity of recruitment parameters and dependent reference points. Our results demonstrate the power of PPM for synthesizing the form and pattern of recruitment time‐variation among regions, including general summaries of directional change over time. Furthermore, our results show regional differences in time‐varying patterns, particularly the signal‐to‐noise ratio (SNR) of low‐ to high‐frequency variation. The SNR was lower in the California Current region than in two Atlantic regions and two Alaska regions. Generalized linear modelling used to synthesize results suggests that stocks with higher contrast in spawning stock biomass over time, standardized regardless of actual spawning stock size, were more likely to have time‐varying productivity than stocks with low contrast. The likelihood of time‐variation in productivity of a given stock was also found to be closely related to the autocorrelation of the recruitment time series. Such inter‐regional and inter‐stock comparisons of variation are vital in understanding the roles of local and global environmental change on fish productivity. [ABSTRACT FROM AUTHOR]

Fish farming is increasingly important globally and nationally, playing a crucial role in fish production for human consumption. Monitoring microbiological and chemical contaminants from water discharge is essential to mitigate the risk of contaminating water and fish for human consumption. This study analyzes the physicochemical and E. coli parameters of water and tambacu fish muscles (Colossoma macropomum × Piaractus mesopotamicus) in Western Maranhão, Brazil. It also includes a qualitative characterization of zooplankton in the ponds. Samples were collected from tambacu ponds in a dam system fed by natural watercourses from the Tocantins River tributaries, located at the connection of the Brazilian savanna and Amazon biomes. The physicochemical and E. coli parameters of water did not meet national standards. The zooplankton community included Rotifera, Cladocera, Copepoda, and Protozoa representatives, with no prior studies on zooplankton in the region, making these findings unprecedented. The biological quality of freshwater is crucial in fish farming, as poor quality can lead to decreased productivity and fish mortality, raising significant food safety concerns. The water quality studied is related to the potential influence of untreated wastewater as a source of contamination, leaving the studied region still far from safe water reuse practices. The findings on chemical and E. coli contamination of fish farming waters concern human health and emphasize the need for appropriate regulations. [ABSTRACT FROM AUTHOR]

This research examined the impact of incorporating cinnamon meal (CM), water cinnamon extract (CEX), and its combination on fish productivities, blood parameters and economic outcomes over 56 days. Five groups of fish were fed different diets: a control diet (D1), 1% cinnamon meal (D2), 1% water cinnamon extract (D3), combinations of 0.5% CM and 0.5% WCEX (D4), and 1% CM and 1% WCEX (D5). All diets were iso-caloric and iso-nitrogenous. Significant improvements in growth performances and feed utilization parameters were observed (P<0.05) in D5 (1% CM and 1% WCEX) compared to control or other treatments, with 100% survival in the D2, D4, and D5 groups, compared to 93.33% in D1 and D3. Feed conversion ratio improved with cinnamon-treated diets, and serum protein and globulin levels increased significantly, while cholesterol levels decreased. Body composition analysis showed a significant reduction in OM and CP, while DM, EE, ash, and GE content increased. The economic return improved in cinnamon-treated groups, though the percentage of profitable value decreased slightly. Diet costs were reduced, and net improvement over the control ranged from 2.32 to 8.82%. In conclusion, adding cinnamon meal and/or cinnamon water extract to fish diets impacted growth and feed efficiency positively, without negative effects. [ABSTRACT FROM AUTHOR]

In recent years, biofloc technology has grown rapidly for various reasons, including improved water quality, cost-effectiveness, sustainability, and environmental friendliness. Therefore, the purpose of this study was to evaluate the impact of fish culture systems (a traditional system (TRS) and biofloc system (BFS)) on growth, hematological parameters, serum biochemical markers, and flesh quality of O. niloticus reared in different stocking densities (SDs). A total of 900 on-grown O. niloticus, weighing 53.17±3.32g, as initial body weight, were randomly distributed into continuously aerated tanks in two different culture systems (BFS and TRS) and stocked at densities of 50 and 100 fish/m3 for 60 days. As the SD increased, all growth performance and feed efficiency indices decreased significantly. Fish reared in the BFS showed superior growth performance and feed conversion ratio (FCR) compared to the TRS group. Fish stocked in the BFS at a density of 100 fish/m3 showed much better growth performance than TRS. Hematological indicators were enhanced in fish cultured in the BFS, especially at higher SD. Conversely, fish reared in the TRS displayed significant increases in levels of serum cortisol, glucose, total cholesterol, and triglycerides than fish reared in the BFS. Fish stocked at SD of 100 fish/m³ and reared in the BFS exhibited a significant decrease in cortisol levels and improvements in flesh quality, as indicated by decreased drip loss and frozen leakage rate compared to those in the TRS. Overall, the findings indicate the BFS's ability to mitigate the adverse effects of increasing SD on fish, emphasizing its potential as a promising technology for enhancing fish productivity and obtaining a healthy product. [ABSTRACT FROM AUTHOR]

Fisheries in India are a burgeoning industry with immense potential and opportunities. Ironically, because of its enormous but untapped potential, reservoir fisheries are called as "a sleeping giant". The average productivity from these reservoirs in India is about 30 kg/ha compared to the production potential of 250 kg/ha. Inadequate management leads to low rate of fish production in Indian reservoirs. A major impediment to science -based fish productivity in reservoirs is the lack of authentic data on target stocks. Inland fisheries, like those in reservoirs, are particularly affected. Investigators generally rely on simple catch statistics and hypothesis statements to assess fish production and potential yields due to inadequate resources, population data, and experts in the area. The present paper emphasizes the quintessential 44sq km huge Tehri hydro-power dam reservoir, located in the Bhagirathi and Bhilangana valleys of the lesser Himalayas in the Garhwal hills. On average the fish productivity from Tehri reservoir in the year 2021-2022 is reported as 13.75 kg/ha but, this is significantly lower than its actual productivity. Thus, the current technical paper addresses this issue by condensing and synthesizing the current status of fisheries in the Tehri Dam reservoir with past status in terms of fish species diversity. It provides baseline information on fish production and various data shortfalls in fisheries activity management. The paper also describes the ecological and economic aspects that affect fish catch to utilize the reservoir resources and mired the cold-water fishery management in the Tehri reservoir. [ABSTRACT FROM AUTHOR]

Purpose.To characterize the productive and biological features of the first generation crossbreed carp from the crossbreeding of Antoniny-Zozulenets, Galician and Lyubin inbred types of Ukrainian framed and scaly breeds adapted to cultivation in the conditions of Polissiya. Methodology. The study was conducted at the Lviv Research Station of the Institute of Fisheries of the National Academy of Sciences. The material for the study was crossbred age-0+ and age-1 carps obtained from brood Lyubin (LSC), Galician (GFC) and Antoniny-Zozulenets carps obtained by natural spawning in ponds, according to the following scheme: ♀LSC×♂LSC; ♀LSC×♂AZFC; ♀AZSC×♂LSC; ♀AZFC×♂GFC. The brood stock was kept according to the instructions in the carp breeding. Studies of productive and biological parameters were carried out according to the common methods in fish farming and ichthyology. The heterosis effect for the main productive parameters was calculated by the excess of the corresponding parameter in the crossbreed group over the parameter of the original maternal line. Feeding of age-0+ fish was carried out with ground grain starting from the second decade of July. Winter hardiness of crossbred and pure lines was evaluated by absolute and relative loss of body weight and survival rate. The data obtained in the experiments was subjected to statistical processing in MS Excel (2016). The criteria for the analysis of parameters were their average value and standard error (M±m). Findings. The study showed that the survival rate of purebred age-0+ carps was 52.4%, with an average weight of 26.79±1.83 g. The yield of crossbred age-0+ fish grown in nursery ponds was 51.3%, but their average weight was the highest — 33.97±4.49 g. The yield of age-0+ fish obtained from crossing ♀AZFC×♂GFC grown in concrete ponds was 55.4% and was the highest among all experimental groups. The survival rate of age-0+ fish obtained from crossing ♀AZSC×♂LSC was 53.1%. The individual average weights of age-10+ carps grown in concrete ponds were close and amounted to 15.39±2.01 and 16.45±1.30 g, respectively, according to the experimental groups. Fish productivity in concrete ponds was 255.8 and 261.9 kg/ha. The analysis of wintering showed that the yield from the wintering of age-1 LSC and cross-breeding group ♀LSC×♂AZFC was 81.7% and 76.0%, with higher values of the yield of purebred scaly age-1 fish. At the same time, they also had a lower rate, almost 2% weight loss during the winter — 8.9% versus 10.8% in crossbred framed age-1 fish. Age-1 fish of crossbred groups, which were obtained from Antoniny-Zozulenetsk carp females, had a survival rate of 51.3–55.5% with a weight loss of 12.9–13.1%. Originality. For the first time, the advantages and biological parameters of crossbred groups and individual types of carp from the combination of different structural units, namely Antoniny-Zozulenetsk, Lyubin and Galician inbred types of carps were obtained and studied. Therefore, scientific studies aimed at finding optimal combinations of productive traits of carp, by crossing fish of various structural units not only with desired traits, but also with maximally different genetic characteristics, is particularly important. Practical Value. The obtained results demonstrate the effectiveness of the use of industrial crossing in modern fish farming practice. Taking into account the belonging of each inbred type to ecological and geographical conditions, when crossing breeds of different geographical origins, an increase in the effect of heterosis is observed. Industrial hybridization and its high efficiency in pond fish farming due to the use of heterosis plays an important role in increasing the fish productivity of pond farms.

This study addressed the urgent need for sustainable protein sources in aquaculture due to the depletion of marine resources and rising costs. Animal protein sources, particularly poultry by-product meal (PBM) and insect exuviae meal, were investigated as viable alternatives to fishmeal (FM). The research study confirmed the successful replacement of FM with a combination of PBM and insect exuviae meal (up to 50%) in the diet of European seabass without compromising growth, feed conversion, gut health, and liver fat content. In particular, growth was robust with both PBM formulations, with the 25% PBM diet showing better results. Histological examinations showed good gut and liver health, contradicting the concerns of previous studies. This paper emphasizes the importance of holistic analyzes that go beyond growth parameters and include histomorphological investigations. The results show that PBM in combination with insect/exuviae meal is well tolerated by seabass, which is consistent with reports in the literature of it mitigating negative effects on gut health. A detailed analysis of the microbiota revealed a decrease in the Firmicutes/Proteobacteria ratio due to an increase in potentially pathogenic bacteria. However, the formulation containing insect exuviae partially counteracted this effect by preserving the beneficial Lactobacillus and promoting the synthesis of short-chain fatty acids (SCFAs), particularly butyrate. Chitin-rich components from insect exuviae were associated with improved gut health, which was supported by the increased production of SCFAs, which are known for their anti-inflammatory properties. This paper concludes that a combination of PBM and insect/exuviae meal can replace up to 50% of FM in the diet of seabass, supporting sustainable aquaculture practices. Despite some changes in the microbiota, the negative effects are mitigated by the addition of insect exuviae, highlighting their potential as a prebiotic to increase fish productivity and contribute to a circular economy in aquaculture. [ABSTRACT FROM AUTHOR]

Climate change continues to exert pressure on ocean ecosystems. The fisheries‐related responses, such as altered body growth, recruitment and spatial distribution of the targeted stock(s), have generally been reasonably well investigated. Nevertheless, there are still important knowledge gaps in how biophysical drivers impact stock productivity and thereby sustainable harvest levels. Considering this, we investigated 26 fish stocks in the Northeast Atlantic, a region characterized by accelerated climate change effects and a diverse set of fisheries. A novel, stepwise, Bayesian framework to quantify stock productivity was established to identify shared trends and project future patterns, aiming at determining essential baselines for adaptive fishery management in the face of climate change. Despite variation among large marine ecosystems and stocks, an overall declining trend in productivity over the past four decades was observed, especially in high‐latitude areas. These hindcast results were mainly attributed to higher temperatures posing negative effects on productivity, which was dependent on the stock's thermal preference. Contrastingly, the proxy for food availability – gross secondary production – exhibited less consistent impacts. In the forecast, the applied Shared Socio‐economic Pathways (SSPs) indicated that most stocks are likely to encounter adverse effects, with the worst cases expected to occur under SSP2‐4.5 in the 2050s, and under SSP5‐8.5 in the 2090s. Thus, this study generally not only supports earlier climate vulnerability assessments ('scorings') of experts but also provides evidence for revised directional effects under climate change, underlining the complexity of processes affecting stock productivity. [ABSTRACT FROM AUTHOR]

Seagrass meadows provide an important nursery and feeding habitat for fish, globally. However, limited data exist on how these vegetated coastal ecosystems affect local fish stocks over longer time periods. By means of beach seine hauling with a bio‐monitoring seine net, we collected fish data in Kronborg Bay (Denmark) over 4 years. The bay contains both vegetated and bare sediment areas in close proximity to Kronborg Castle in Elsinore and is part of the Øresund strait; a dynamic marine environment linking the Baltic Sea with the inner Danish waters (Kattegat). We investigated the biodiversity and fish abundance in a healthy seagrass meadow and compared it with a bare adjacent sediment area. We show that seagrass is important for fish species like the Atlantic cod, the two‐spotted goby, and the broadnosed pipefish. The seagrass meadow harboured more fish species and higher biodiversity, while the number of individuals was higher in the adjacent bare sediment area as a result of high abundances of lesser sand eel. Pilou's evenness and the Shannon‐Wiener index showed 2–4‐fold higher biodiversity in the seagrass meadow. The seagrass meadow harboured about 35% more fish species than the bare adjacent sediment. The Atlantic cod was almost entirely found in the seagrass meadow, while lesser sand eel that showed an overall increase in abundance in both habitats, represented the largest proportion of the total number of fish individuals (up to about 60%) and was mostly found on the bare adjacent sediment. Species abundance was analysed for changes over time, where, for example the European plaice showed an increase in abundance over the 4‐year period of investigation. Seagrass meadows can thus be very important for the Atlantic cod population in the Øresund strait and generally for local fish productivity, abundance and diversity. [ABSTRACT FROM AUTHOR]

Purpose. To characterize the productive and biological features of the first generation crossbreed carp from the crossbreeding of Antoniny-Zozulenets, Galician and Lyubin inbred types of Ukrainian framed and scaly breeds adapted to cultivation in the conditions of Polissiya. Methodology. The study was conducted at the Lviv Research Station of the Institute of Fisheries of the National Academy of Sciences. The material for the study was crossbred age- 0+ and age-1 carps obtained from brood Lyubin (LSC), Galician (GFC) and Antoniny-Zozulenets carps obtained by natural spawning in ponds, according to the following scheme: ♀LSC×♂LSC; ♀LSC×♂AZFC; ♀AZSC×♂LSC; ♀AZFC×♂GFC. The brood stock was kept according to the instructions in the carp breeding. Studies of productive and biological parameters were carried out according to the common methods in fish farming and ichthyology. The heterosis effect for the main productive parameters was calculated by the excess of the corresponding parameter in the crossbreed group over the parameter of the original maternal line. Feeding of age-0+ fish was carried out with ground grain starting from the second decade of July. Winter hardiness of crossbred and pure lines was evaluated by absolute and relative loss of body weight and survival rate. The data obtained in the experiments was subjected to statistical processing in MS Excel (2016). The criteria for the analysis of parameters were their average value and standard error (M±m). Findings. The study showed that the survival rate of purebred age-0+ carps was 52.4%, with an average weight of 26.79±1.83 g. The yield of crossbred age-0+ fish grown in nursery ponds was 51.3%, but their average weight was the highest -- 33.97±4.49 g. The yield of age-0+ fish obtained from crossing ♀AZFC×♂GFC grown in concrete ponds was 55.4% and was the highest among all experimental groups. The survival rate of age-0+ fish obtained from crossing ♀AZSC×♂LSC was 53.1%. The individual average weights of age-10+ carps grown in concrete ponds were close and amounted to 15.39±2.01 and 16.45±1.30 g, respectively, according to the experimental groups. Fish productivity in concrete ponds was 255.8 and 261.9 kg/ha. The analysis of wintering showed that the yield from the wintering of age-1 LSC and cross-breeding group ♀LSC×♂AZFC was 81.7% and 76.0%, with higher values of the yield of purebred scaly age-1 fish. At the same time, they also had a lower rate, almost 2% weight loss during the winter -- 8.9% versus 10.8% in crossbred framed age-1 fish. Age-1 fish of crossbred groups, which were obtained from Antoniny-Zozulenetsk carp females, had a survival rate of 51.3-55.5% with a weight loss of 12.9-13.1%. Originality. For the first time, the advantages and biological parameters of crossbred groups and individual types of carp from the combination of different structural units, namely Antoniny-Zozulenetsk, Lyubin and Galician inbred types of carps were obtained and studied. Therefore, scientific studies aimed at finding optimal combinations of productive traits of carp, by crossing fish of various structural units not only with desired traits, but also with maximally different genetic characteristics, is particularly important. Practical Value. The obtained results demonstrate the effectiveness of the use of industrial crossing in modern fish farming practice. Taking into account the belonging of each inbred type to ecological and geographical conditions, when crossing breeds of different geographical origins, an increase in the effect of heterosis is observed. Industrial hybridization and its high efficiency in pond fish farming due to the use of heterosis plays an important role in increasing the fish productivity of pond farms. [ABSTRACT FROM AUTHOR]

Fish Aggregating Devices (FADs) are essential supplementary structures used in tropical tuna purse-seine fishing. They are strategically placed to attract tuna species and enhance fishing productivity. The hydrodynamic performance of FADs has a direct effect on their structural and environmental safety in the harsh marine environment. Conventional FADs are composed of materials that do not break down naturally, leading to the accumulation of waste in the ocean and potential negative effects on marine ecosystems. Therefore, this work aimed to examine the hydrodynamic performance of biodegradable drifting FADs (Bio-DFADs) in oceanic currents by numerical modelling. The Reynolds-averaged Navier–Stokes equation was used to solve the flow field and discretized based on the realizable k-ε turbulence model, employing the finite volume method. A set of Bio-DFADs was developed to assess the hydrodynamic performance under varying current velocities and attack angles, as well as different balsa wood diameters and sinker weights. The results indicated that the relative current velocity significantly affected the relative velocity of Bio-DFADs. The relative length of the raft significantly affected both the relative velocity and the relative wetted area in a pure stream. Finally, the diameter of the balsa wood affected the drift velocity, and the sinker's relative weight affected the hydrodynamic performance of the Bio-DFADs. [ABSTRACT FROM AUTHOR]

Growth stagnation in early‐maturing fish is a concern for higher fish productivity and may be regulated with reproductive arrest using phytochemicals. In this line, the study attempts to improve the growth of silver barb, Barbonymus gonionotus, through dietary pawpaw (Carica papaya) seed (PS) supplemented diets during a 60‐day trial (30‐days of feeding PS, followed by a 30‐day recovery period). Four levels of PS at 0, 2, 4, and 6 g kg−1 diet were added to a commercial feed (32% crude protein) and fed to advanced fingerlings (19.08 ± 0.02 g) at 3% body weight, which forms the experimental groups, designated as control, T1, T2, and T3. Subsequent alterations in growth (% weight gain and specific growth rate), reproduction (gonadosomatic index (GSI) and gonadal histology), and physiological function (haematology and stress biomarkers, viz., cortisol and glucose) were examined at the end of the experiment. Observations noted at the end of the trial showed significantly (P < 0.05) enhanced growth in groups fed 2 g kg−1, but not significantly with control. GSI showed an extreme reduction in all groups as the level of supplementation increased with the lowest being noted in T3. Sex change was observed in T2 and T3, wherein only male populations were noticed. Gonadal histology demonstrates tissue‐level generation in T1, compared with control. Tissue alteration (atrophy and necrosis) was noticed in the T2 and T3. The haematological profile indicates a gradual decrease in erythrocyte and leucocyte counts, packed cell volume, and haemoglobin in the T2 and T3 groups, compared with the T1 and control groups (P < 0.05). Serum biochemistry followed a similar trend. The levels of blood glucose and cortisol were higher in T2 and T3 (P < 0.05) than in the control and T1. The overall findings from this study reveal that dietary PS supplementation at 2 g kg−1 can enhance the growth of silver barb; however, higher doses suppress both growth and reproductive function, resulting in subsequent disturbances in physiology. Further studies regarding the molecular mechanism of such an outcome warrant immediate investigation. [ABSTRACT FROM AUTHOR]

Biomass production is a key ecosystem process that provides insight into ecological processes such as growth, reproduction, mortality, and energy distribution. Previous studies have considered various fish response measures such as species richness, abundance, and/or biomass as response variables for river ecosystems or the productivity of particular species. However, few studies have investigated how total fish productivity of riverine systems is affected by environmental variables. Here, we identified important abiotic and biotic predictors of fish productivity in wadeable, temperate riverine systems.We investigated the relationships between total stream fish productivity and multiple abiotic and biotic variables in wadeable stream reaches across Ontario, Canada. Variance partitioning was used to evaluate the relative importance of the biotic, landscape, climatic, and geologic variables on total stream fish productivity. A modified bootstrap approach was used for the model‐selection process and to parameterise an empirical fish productivity model.We found that biotic predictors explained more variation in productivity relative to the abiotic variables. The best empirical model included day‐of‐year, growing degree days, latitude, salmonid presence/absence, species richness, and upstream catchment area.Our findings indicate that a combination of both biotic and abiotic variables can provide valuable insight into how ecological processes, such as fish productivity, differ across ecosystems. Species richness and differences in assemblage characteristics may be key determinants of the overall fish productivity in stream systems. Our model can estimate productivity from salmonid presence/absence data and total species richness, instead of fish abundance data, which require larger sampling efforts. [ABSTRACT FROM AUTHOR]

Food availability influence the state of fish stocks, with effects on the demographics, composition and productivity of fish populations. In the spring seasons of 2018–2020, expeditions were carried out in order to collect data for Sprattus sprattus agglomerations, mesozooplankton community and S. sprattus stomach content analysis. Throughout the whole study period, it was shown that the fodder mesozooplankton component recorded high concentrations in the areas where fish had high catch values, promoting the best possible development of fish stocks. The analysis of S. sprattus stomach content highlighted the high consumption of copepods and meroplanktonic elements, with copepods being intensively consumed in 2019 and 2020. Fish productivity is directly associated with the presence or absence of mesozooplankton, which can have a cascading effect on fish stocks. [ABSTRACT FROM AUTHOR]

Osun River is a major river in the Ogun-Osun River Basin and contributes significantly to fish production and quality source of protein. It is therefore essential to investigate the condition and characteristics of the most abundant fish species in the river. This aim of this study was achieved by investigating the Morphometric parameters, sex ratio, and condition factor of Oreochromis niloticus and Chrysichthys nigrodigitatus in the lower section of the river, because these fish species were the most abundant and economically important. Monofilament gillnets were used for fish sampling for twelve months to cover both wet and dry seasons (November 2017 to October 2018). A total of 1597 individuals of both species were collected comprising 40.14% O. niloticus samples and 59.88% samples of C. nigrodigitatus. The correlation coefficient (r) for O. niloticus and C. nigrodigitatus were 0.78 and 0.89 which indicated a high and very high relationship respectively. O. niloticus showed a significant negative allometric growth pattern (b = 2.315) while C. nigrodigitatus showed a growth pattern that was significant and positively allometric (b = 3.102). The mean condition factor (K) was 2.8 for O. niloticus and 1.9 for C. nigrodigitatus. The sex ratio of male to female was 1.5:1 for O. niloticus and 1.2:1 for C. nigrodigitatus. Both fish species responded well due to the high K-factor and good growth rate, and it is therefore essential to maintain optimal environmental factors for the sustainability of these fish species in the river. [ABSTRACT FROM AUTHOR]

Seagrass habitats play a major role in fisheries productivity through nursery functions and feeding grounds for diverse fish species. However, little is known about the seasonal distribution of fish larvae at large spatial scales in coastal East Africa. We investigated drivers of the seasonal fish larvae abundance and composition in seagrass habitats in Kenya and Tanzania. We found a high diversity of fish larvae (54 families) inhabiting seagrass habitats that differed between sites and seasons. Fish larvae abundance were highest in Kenya, particularly during the northeast monsoon season. Overall, total larval abundances per site were low, reaching less than 190 individuals/100 m3 in Kenya and less than 40 individuals/100 m3 in Tanzania, likely related to the low productivity and strong hydrodynamic processes in this region. Our data suggests that most of the fish spawn year-round in these tropical waters as we did not find strong seasonal patterns. All sites had a high relative abundance of larvae from demersal spawning fishes, indicating that many fish species move to coastal sites for spawning. Primary productivity and dissolved oxygen, driven by hydrodynamics conditions are positively related to fish larvae productivity both in Kenya and Tanzania. These findings indicate that the occurrence of both resident and transient fish larvae in seagrass meadows is driven by strong hydrodynamic and tidal processes that transport fish larvae across adjacent habitats. [ABSTRACT FROM AUTHOR]

Coastal and estuarine habitats are essential for both growth and survival at juvenile stages for a large proportion of marine fish but are exposed to a variety of threats. However, the quantitative impacts of anthropic‐mediated nursery degradation on exploited population dynamics and productivity are rarely addressed. We developed a comprehensive steepness‐based parameterization of the stock–recruitment relationship that directly depends upon juvenile habitat quality and surface area and used a generic age‐ and stage‐structured model to simulate exploited population dynamics under nursery degradation/restoration scenarios. Population responses to juvenile habitat modification were estimated for three species with contrasting life histories. Modifying the surface area of nursery habitat has a predictable direct scaling effect on population size and affects biomass and fishing yield, with identical responses observed for various life histories. Modification of habitat quality affects both the population size and the shape of the productivity curve, leading to more complex responses of biomass and fishing yields that depend upon combinations of life history traits. Populations with low steepness and hence lower resiliency to fishing are the most sensitive to the degradation of habitat quality. Our study emphasizes the critical impact of juvenile habitat modification on population dynamics and productivity and the need to integrate habitat consideration into the management of exploited marine species. Our modelling framework is generalizable and can be extended to handle many diverse life histories and case studies to quantify the consequences of coastal habitat degradation/restoration for the dynamics of exploited marine fish populations. [ABSTRACT FROM AUTHOR]

Despite continued calls for the application of ecosystem‐based fisheries management, tactical fisheries management continues to be heavily reliant on single‐species stock assessments. These stock assessments rarely quantitatively integrate the effects of ecosystem processes on fish stock productivity. This lack of integration is ultimately driven by the complexity of interactions between populations, ecosystems and fisheries, which produces uncertainty when defining which processes to include and how to include them. Models developed using a structured hypothesis testing framework would allow formalizing uncertainties while underscoring the importance of incorporating different population and ecosystem processes to explain non‐stationary stock productivity. Here, we develop a conceptual framework for extending and comparing population dynamics models of increasing complexity. We illustrate the utility of the framework by investigating the population and ecosystem processes that most likely affected the differential recovery of two flatfish populations (American plaice and yellowtail flounder) on the Newfoundland Grand Banks over the past three decades. We found that yellowtail flounder population dynamics were primarily driven by recruitment variability, which was negatively affected by warmer climatological conditions, as indicated by an integrated regional climate index. Meanwhile, American plaice population dynamics were affected by a combination of temporal variability in recruitment and natural mortality, where natural mortality increased during colder than average conditions. By exploring hypotheses about the effects of population and ecosystem processes on population dynamics, this modelling framework will improve understanding about the drivers of shifts in population productivity while serving as a transparent and robust approach to support ecosystem‐based fisheries management. [ABSTRACT FROM AUTHOR]

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Introduction: Nigeria is Africa's most populous country, third largest fish producer, and second largest aquaculture producer. There have been numerous studies of aquaculture and fisheries in Nigeria, but no study to date has analyzed aquaculture and capture fisheries value chains together, while giving equal weight to all value chain segments and systematically capturing information on temporal trends in value chain structure, conduct, and performance. This paper does so. Methods: We conducted a structured, qualitative, rapid reconnaissance survey of 180 actors from eight segments of the aquatic food value chain in three Nigerian states with contrasting geographies, Ebonyi, Kebbi, and Oyo. Results: Results particularly important for future research and policy are as follows. (1) Partial vertical integration is a common feature of the organization of firms in all value chain segments, as a risk reduction strategy to overcome market imperfections and frictions. Scarcity and high cost of imported intermediate inputs is stimulating local innovation and import substitution manufacturing of feeds and fabricated items. (2) Inter-sectoral spillovers from the poultry industry have hastened the development of fish value chains, while improvements in power supply have enabled the expansion of cold storage capacity, facilitating the geographical lengthening of frozen fish value chains. (3) Rapid technological and/or institutional change is occurring in all value chain segments, including those usually viewed as traditional, such as processing and fishing. Logistics services are becoming more specialized and sophisticated, and digital communications technologies including social media play an increasingly important role in value chain coordination and marketing. (4) Increasing opportunity costs of time drive demand for convenience foods such as smoked and fried fish, which require little further preparation and can be stored at room temperature. Demand for farmed catfish is linked to growing consumption of food away from home at bars and restaurants. (5) Significant opportunities exist to improve the performance of value chains in terms of gender equity, environmental impacts, and food safety. [ABSTRACT FROM AUTHOR]

Shellfish reefs across the world have been heavily degraded by mechanical harvesting, disease and declining water quality. In southern Australia, where substantial losses have occurred, government and non‐government efforts to restore functioning reefs are now underway with a strong focus on enhancing fish productivity. However, the capacity of these restored reefs to enhance fish production remains unknown, hampering estimates of return on investment.We quantify the density differences of newly recruited juvenile fish and other nekton on these restored reefs, relative to those on unrestored, unstructured habitat. Fish were surveyed at three paired reef‐unstructured locations using 169 unbaited stereo video deployments during three periods over 12 months (2022–2023). We used automation software, FishID, to automatically identify, size and count fish in videos. We subsequently applied known growth and mortality parameters to model enhancement of fish productivity.Sixteen species occurred as new recruits, with all but two found at higher densities on reefs than unstructured habitat. Enhancement of fish production from subtidal restored shellfish reefs from a single year's cohort is estimated to be, on average, 6186 kg ha−1 year−1 (SD 1802) after enough time has elapsed for all species to have matured. Species harvested commercially or recreationally contributed 98% of that production (6083 kg ha−1 year−1, SD 1797).Enhancement varied greatly among locations, ranging from 12,738 kg ha−1 year−1 (SD 2894), which is the highest yet recorded anywhere, to 1.4 kg ha−1 year−1 (SD 0.9).The lack of juvenile fish at the location with the lowest estimated enhancement might be explained by the impact of overfishing on recruitment of key species or by an abundance of alternative habitat for juvenile fish.Synthesis and applications. The combination of underwater videos with automated data extraction provides a reliable, cost‐effective method for surveying fish on oyster reefs. By quantifying enhanced fish productivity on reefs, we provide estimates that will underpin calculations of ecological, social and financial benefits, supporting the business case for scaling‐up restoration efforts. [ABSTRACT FROM AUTHOR]

Herbivorous fishes play important roles on coral reefs, acting as key trophic conduits of primary productivity. Whilst these roles are widely appreciated on tropical reefs, the relative contribution of fishes which inhabit marginal reefs, such as Prionurus surgeonfishes, is not well understood. Here, we examine the extent to which herbivorous fish productivity varies amongst global ecoregions, specifically considering the relative contribution of Prionurus. We also compare the productivity of Prionurus to that of other herbivorous fishes in relation to water temperatures. Our analysis revealed that the Eastern Galápagos Islands support the highest levels of herbivorous fish productivity recorded to date, with Prionurus laticlavius accounting for over 94% of that productivity. Moreover, Prionurus productivity peaked at relatively cool water temperatures (~ 22–25 °C), although patterns were driven by P. laticlavius. These results highlight the exceptional herbivorous fish productivity in the Eastern Galápagos Islands and the disproportionate contribution of P. laticlavius in this locality. [ABSTRACT FROM AUTHOR]

Coral reefs are highly productive ecosystems, in part due to the productivity of planktivorous fishes. The planktivorous fish community contains two distinct groups which target either the gelatinous or the non-gelatinous fractions of the incoming zooplankton. However, the nutritional value of these prey fractions and, consequently, their potential contribution to planktivorous fish productivity are poorly understood. We explored the zooplankton fractions potential contribution to planktivorous fish productivity (our function of interest), by quantifying the nutritional content a key trait of the gelatinous and non-gelatinous prey fractions which are accessible to reef-associated diurnal planktivores. By combining vertical plankton tows with stoichiometric analyses, we found that the three zooplankton community fractions—gelatinous, > 2 mm non-gelatinous and < 2 mm non-gelatinous—were all relatively good sources of nitrogen, with median C:N values of 4.81:1, 4.22:1 and 4.62:1, respectively. The delivery of gN m−2 to our study reef over a flood tide was then estimated. The abundant < 2 mm non-gelatinous community delivered the largest gN m−2 (median: 0.88 gN m−2 6 h−1), which was estimated to be one to two orders of magnitude greater than the delivery from the > 2 mm non-gelatinous (0.06 gN) and gelatinous (0.03 gN) communities, respectively. Overall, our results highlight the quality of both gelatinous and non-gelatinous zooplankton as prey for planktivorous fishes, emphasizing the potential importance of the often-overlooked gelatinous fraction. [ABSTRACT FROM AUTHOR]

[Objective] To scientifically evaluate fish productivity in Lianhuatai Reservoir, and make use of fishery resources, and conserve the aquatic ecosystem. [Method] In March 2022, the aquatic organism resources in this reservoir were investigated and monitored. According to the related standards, the fish productivity and stockings of silver carp and bighead carp fingerling were calculated. [Result]The phytoplankton in this reservoir belonged to 21 species of 6 phyta, the average density was 27. 194×10 6 cells/ L, the average biomass was 4. 803 3 mg / L. Zooplankton was belonged to 20 species of 14 genera, the average density was 189. 5 ind. / L and the average biomass was 0. 560 mg / L. The bentonic organisms belonged to 3 species of 2 categories, the average density was 66. 66 ind. / L, and the average biomass was 3. 837 g / m ² . Total fish productivity of this reservoir was 416. 34 t, the fish productivity of phytoplankton and zooplankton was 295. 19 t, the fish productivity of benthic feeding fish was 3. 07 t, the fish productivity provided by humus, organic debris and bacteria was 118. 08 t. According to the analysis results of fish productivity, the stocking densities of silver carp and bighead carp fingerlings were 1 067 ind. / hm ² and 344 ind. / hm ² respectively. [Conclusion] The reservoir had greater fish productivity. Through reasonable development and utilization, better economic benefits could be obtained and healthy aquatic ecosystem could be ensured. [ABSTRACT FROM AUTHOR]

China has been the top aquaculture producer in the world since 2002. Over 800 species and 240 improved varieties have been used in China's aquaculture, which is the most diverse collection of species on this planet. Species diversification, along with other aquaculture technologies, contributes significantly to the increase of China's aquaculture production, whereas the use of too many species in aquaculture has resulted in some issues related to the environment and sustainability. We provide an updated overview of the species currently used in Chinese aquaculture in this paper. We examine critically the main drivers of species diversification in China with examples. We also introduce Chinese approaches to improve and certify new species and varieties for commercial production. We believe that further species diversification is not a priority in China's aquaculture, while further improvement of aquaculture technologies for major and native species is essential for green, profitable, and sustainable (GPS) aquaculture. The implications of China's experiences with species diversification for global aquaculture species diversification are discussed. [ABSTRACT FROM AUTHOR]

This experiment was designed to examine the impacts of different dietary protein levels (DPLs) and their interaction on the growth and some physiological indices of juvenile striped catfish, Pangasianodon hypophthalmus, reared at different stocking densities (SDs) for 15 weeks. A total of 1440 striped catfish (initial weight = 10.0 ± 2.2 g) were randomly allocated into six equal treated groups (three replicates per treated group). Fish were fed two DPLs of 25 % and 30 % and reared under different SDs of 20, 40, and 60 fish/m3. The obtained results indicated that with increasing DPL, growth parameters, and digestive enzyme activities, the liver function enzyme activities, serum protein constituents' levels, and concentrations of thyroid hormones significantly increased, while levels of serum glucose, total cholesterol, and triglycerides remarkably decreased. On the other hand, increasing SD negatively affects growth, digestive and liver enzyme activities, some hematological parameters, and fish-body chemical analysis. The interaction between DPLs and different SDs significantly improved the most estimated parameters with increasing DPLs despite intensifying SDs. In general, afforded striped catfish diets containing 30 % DPL and stocked at 20 fish/m3 presented the best performance, consumed feed efficiency, and health status. Thus, the interaction between DPLs and SDs demonstrated the favorable benefits of increasing DPLs by diminishing some of the adverse impacts generated by high SDs, which may subsequently lead to high production and increased revenues for fish farmers.

Dissolved oxygen (DO) is a critical factor in maintaining healthy aquatic ecosystems, including aquaculture ponds. Low DO levels can lead to hypoxia conditions, which are detrimental to fish health and productivity. To deal with this issue, we intend for a smart monitoring system that predicts hypoxia conditions due to low DO levels in aquaculture ponds. The proposed system collects water quality data using Internet of things (IoT) devices and segments it into different categories based on water quality parameters, with a particular focus on low DO levels. By detecting hypoxia conditions early, fish farmers can take corrective measures to prevent fish mortality and improve fish health. To achieve this, our proposed system uses a lightweight Spatially Shared Attention Long Short-Term Memory (SSA-LSTM) model that captures both temporal and spatial dependencies of DO content in water, enabling accurate prediction of hypoxia conditions. Our model outperforms traditional LSTM models and other existing state-of-the-art models, achieving 99.8% accuracy. The proposed system provides a reliable and efficient solution to monitor hypoxia conditions in aquaculture systems and help fish farmers make informed decisions for optimal fish health and productivity. [ABSTRACT FROM AUTHOR]

Aquaculture operates according to a principle of rational use of nature's trophic base, being in strict correlation with the biological period of growth and development of the fish stock in an area unit. In practice, the period during which the biological material is developing (polyphagy period) is exploited on the one hand, and the period during which the food spectrum is differentiated on the other. This gives polyculture particular advantages over monoculture, thus broadening the possibilities for exploiting the natural food base, when the biological material populated has a different food spectrum. Expanding the food base of ponds leads to increased final productivity. Obtaining and maintaining live food over a longer period of time is the main goal, followed by the processes initiated to achieve phytoplankton and zooplankton production through the administration of different types of manure. [ABSTRACT FROM AUTHOR]

The article presents the results of research on the growth dynamics of rainbow trout from fingerling to marketable fish using feeds with different compositions of components and nutrient contents. For the experiment, two age groups of rainbow trout individuals, control and experimental, were formed, which were kept in tanks with a total volume of 30 m3 and fed with feeds with different nutrient contents. For feeding the experimental fish, dry pelleted feed for trout was used, which has an optimal balance of cost and nutritive value, resulting in high growth rates with a low feed coefficient. The feed is made from high-quality Ukrainian ingredients with good nutritional and flavor characteristics, stimulating fish feed intake, and is balanced in terms of essential nutrients and biologically active substances, which positively affects the physiological condition of salmonid fish and their growth rates. The daily ration was determined depending on the fish's weight and the water temperature in the tanks according to the feed manufacturer's recommendations. The effectiveness of using pelleted compound feeds for trout was evaluated based on indicators such as fish survival, fish productivity, and feed consumption. At the same time, the physicochemical parameters were monitored throughout the entire experimental period. The duration of growing rainbow trout fingerlings was 245 days. As a result, 3230 specimens of fingerlings with a mass of 25.6 g were obtained in the control, and 3400 specimens were obtained in the experiment with a mass of 28.5 g. The yield from the cultivation was 76 % and 80 %, respectively. Fish productivity was slightly higher in the basin where the experimental group of fingerlings was kept. The total weight of the harvested fish from the experimental group was greater by 14.2 kg. To obtain marketable products, rainbow trout fingerlings were stocked in 30 m3 tanks. The average weight of fish in the control group at stocking was 25.6 g, and in the experimental group, it was 28.5 g. 3100 specimens of fingerlings were stocked in each tank. The duration of cultivation was 215 days. 2805 specimens were harvested from the tanks, 250.5 g from the control tank, and 268.5 g from the experimental tank. The total weight of the harvested fish and fish productivity were slightly higher in the fish from the experimental group. As a result of the conducted research, it was established that feeding fish with feeds differing in nutritional value contributes to increasing the productivity of rainbow trout farming. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Soil Sciences & Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ethiopia's largest freshwater lake, Lake Tana, is home to 21 endemic fish species, the majority of which are cyprinids in the genus Labeobarbus. The lake is undergoing numerous ecological changes, including an invasion of water hyacinth (Eichhornia crassipes (Mart.) Solms (WH). The aim of this study was to predict the future fish productivity in Lake Tana by considering the increasing water hyacinth infestation. This was accomplished by analyzing a 12-year fishery-independent time-series data set of Labeobarbus, collected from sites infested and not infested by water hyacinth. The stationarity of the data was investigated using the Augmented Dickey-Fuller (ADF) unit root test. First-order data differencing was applied to solve the non-stationarity data to stationarity. With the same standardized fishing gillnet and the same sites, the CPUE during the dry season decreased from 3,502 grams (3.5 kg/day) in 2010 to 360 grams (0.36 kg) in 2020 at the water hyacinth-infested sites, demonstrating a 90% decrease in the daily catch. A reduction in catch per unit effort (CPUE) is evident at the WH sites in all seasons, and the rate of fall in there was faster than at the non-infested site. Box Jenkin's auto-regressive integrated moving average models (ARIMA) modelling predicted that Labeobarbus CPUE will decline by a threefold % by 2032 compared to the current catch. Based on these results, the most suitable model for all the seasons and areas was confirmed to be ARIMA (0, 1, 0) using the lowest value of Akaike Information Criteria (AIC's). The fish production declines with expanding WH infestation will necessitate integrated water hyacinth reduction strategies, closed area and closed spawning seasons, and mesh size regulations to conserve and utilize the resource sustainably. As Labeobarbus is the only examined species in this study, forecasts should be made for other commercially significant fish species in the Lake, such as Oreochromis niloticus and Clarias gariepinus. [ABSTRACT FROM AUTHOR]

A genomic cluster of Listeria monocytogenes sequence type (ST) 155, serogroup IIa, infections has been identified in the European Union/European Economic Area (EU/EEA) and the United Kingdom (UK). Based on genomic similarity, the cluster can be divided into three sub‐clusters, of which only cases due to sub‐cluster 1 continue to be reported. Sub‐cluster 1 is therefore the focus of this assessment, with 64 cases reported in five EU/EEA countries between 2016 and 2023, of which 17 were in 2022 and 2023 (one in Austria, one in Belgium, eight in Italy, six in Germany, and one in the Netherlands). It includes 10 fatal cases between 2019 and 2023. Sub‐clusters 2 and 3 are historical, with 30 cases reported between 2011 and 2021. Based on case interviews, ready‐to‐eat (RTE) fish products have been implicated as vehicles of infection. National food investigations, traceability, and genomic data identified 34 L. monocytogenes isolates from 12 fish products and one isolate from a fish processing environment within sub‐cluster 1. Sequencing analysis identified a link with two processing plants in Lithuania. In 2022–2023, contaminated fish products from these plants had reached retail markets in Germany and Italy, but there was no information on the product distribution in the other three countries reporting cases. The recurrent detection of the sub‐cluster 1 strain from marketed sealed RTE fish products revealed the persistence of the strain in one processing plant over eight years. Further targeted investigation in the RTE fish production chain is needed to identify the point(s) of contamination. The interruption of the production of RTE fish products in one of the processing plants is likely to reduce infections, but until all sources and sites of contaminations are properly controlled new cases are expected to occur, particularly among vulnerable people (the immunosuppressed and those aged over 75 years). [ABSTRACT FROM AUTHOR]

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Objective: This paper highlights the complexity of marine fish spawner–recruit systems and how they vary across species and ecosystems while providing a universal terminology and framework to evaluate fish reproduction. We emphasize the gonadal development important to assess maturity, fecundity, where and when fish spawn, and transition and sex assignment in protogynous species. Methods: We review and compare reproductive traits in warmwater and coldwater fishes. Reproductive phases for both sexes and protogynous species are defined and histological micrographs presented. New methods are developed to assess maturity; spawning seasonality; peak spawning; and, for protogynous species, sex assignment. Result: Protogyny, extended spawning seasons, and indeterminate fecundity are more common in warmwater than coldwater systems. The following reproductive phases are defined as immature, transitional (sex change), early developing (the first stage of entrainment in the reproductive cycle), late developing (stages needed to complete maturational competence), spawning, regressing (spawning season termination), and regenerating (fish that are mature but outside of the spawning season). A method to assess the certainty of maturity assignment based on reproductive phase and the age and size range sampled is presented, as are best practices to estimate size and age at maturity. To remove the subjectivity from current methods to estimate spawning seasonality, we present a new quantitative method to identify the core spawning season and peak spawning months. Conclusion: A species' ability to adapt to fishing and climate change varies with their reproductive strategy. Improving our understanding of fish reproduction necessitates standardizing methodology and terminology. Impact statementWe demonstrate the complexity of fish reproductive strategies and how reproductive traits are species‐specific and differ between warmwater and coldwater systems, affecting population productivity. We present a unified framework and terminology to describe fish reproduction and new methods to assess key reproductive parameters. [ABSTRACT FROM AUTHOR]

Water quality is an important factor in the process of fish farming. This study aims to determine the application of FBs pressure that can increase the productivity of comet goldfish Carassius auratus farming in an aquaponic system. The research was carried out from January to March 2022 at the Ciparanje Green House, Faculty of Fisheries and Marine Sciences, Padjadjaran University, Jatinangor. This study used a completely randomized design (CRD) experimental method with four treatments and three replications. The treatment used was the application of FBs pressure of 0 atm (A), 5.25 atm (B), 5.5 atm (C), and 5.75 atm (D). Maintenance of test fish for 30 days with ad satiation feeding. Observation of fish growth through sampling is done by taking fish 10% of the total population randomly in each pond. Data were analyzed using the F test at a 95% confidence level, followed by Duncan's multiple range test with a 95% confidence level, while water quality data were analyzed descriptively. The results showed that the specific daily growth rate of FBs 5.75 was 2.51%, the absolute length growth was 3.33%, the absolute weight growth was 1.70 g and the fish survival rate was 99.3%. It was concluded that the use of FBs in the aquaponic system can increase production of the system. [ABSTRACT FROM AUTHOR]

Background. The article considers a special type of reservoirs – partially regulated sections of riverbeds and streams formed by hydraulic structures and other artificial obstacles on the example of the Nadezhdinskiy reservoir on the Truev river in Penza region. The purpose of this work is to assess the fish productivity of a pond-type riverbed water-lifting reservoir based on a forage base, ichthyofauna in comparison with the natural riverbed and to determine methods of its fisheries use. Materials and methods. Fisheries research at the Nadezhda reservoir and the Truev river was carried out in August 2017. The selection and processing of hydrobiological and ichthyological samples was carried out according to generally accepted methods used by us in the last decade in small watercourses and reservoirs of the Volga region. Results. The regulated section of the Truev river, referred to as the Nadezhda reservoir, is 8–53 times higher in terms of phytoplankton, zooplankton and zoobenthos biomass than the natural riverbed. Also, the ichthyomass in the reservoir is 4.7 times higher than in the river, in which there were no commercial fish species in the studied area. Fish productivity for the most demanded components of the feed base by local fish species in the Nadezhdinskiy reservoir amounted to 166 kg/ha, in the natural channel of the Truev river – 11 kg/ha. The potential fish productivity may be 115 kg/ha and 13.2 kg/ha, respectively. In general, the total fish productivity differs by 12 times. Due to such high productivity, the Nadezhdinskiy reservoir can be used for sports and amateur fishing, pasture or commercial fish farming. Conclusions. The pond-type water-lifting reservoir is characterized by fish productivity at the level of average indicators of fish ponds and reservoirs of complex purpose in Penza region and the Republic of Mordovia. Channel water-lifting reservoirs should be taken into account in the fund of pond fishing in the region and actively exploited, which will significantly increase the volume of aquatic biological resources in low-water regions.

Background. The development of “artisanal” aquaculture, fish farming, fish cultivation in reservoirs of complex purpose is given great importance, both at the global level, in the Russian Federation and in Penza region. This was facilitated by the presence of numerous ponds and small reservoirs of complex purpose, dispersed throughout the region. However, despite the high growth rates of fish production in the region as a whole, the fishproductivity of the reservoirs used remains quite low. To develop methods for optimal cultivation of aquaculture facilities and rational use of aquatic biological resources, it is necessary to know the real picture of the productivity of the forage base of the reservoirs of the region, taking into account modern climatic changes, since the current standards of fish farming for Penza region are clearly outdated. For these purposes, we have chosen an artificial reservoir that is not subject to direct anthropogenic impact, without representatives of the ichthyofauna. The purpose of this work is to determine the real natural fish productivity in a shallow reservoir on the basis of a natural food base for fish free from representatives of the ichthyofauna. Materials and methods.General observations of the shallow reservoir and its aquatic inhabitants were constantly carried out in 2014–2021. Sampling of zooplankton, zoobenthos, necton, neuston, macrophytes was carried out in the non-freezing period from April to November. The samples were processed in accordance with generally accepted methods. Calculations of fish products were carried out using up-to-date data on P/V coefficients, feed coefficients for individual feed components (taking into account their digestibility). Which are used in scientific research and practical work to determine theconsequences of a negative impact on the state of aquatic biological resources and their habitat. Results.Fish production by the main components actively used by the local ichthyofauna (zooplankton, zoobenthos, necton, neuston) can reach 356–427 kg/ha in May–June. The total fish production, taking into account the potential components of the food base (phytoplankton, macrophytes) consumed by herbivorous cultivated fish, may amount to 427–502 kg/ha, respectively. For comparison, the average natural forage base of eutrophic reservoirs of the region with native ichthyofauna not used by fish for food in the summer period is 135.1 kg/ha, the average total productivity of the reservoir, taking into account thefish living in it, is 508 kg/ha. When carp is grown by one-year-olds, the real natural fish productivity of a shallow reservoir in this zone during the growing season of commercial fish can be 400–500 kg/ha. Conclusions.The results obtained in a shallow reservoir without representatives of the ichthyofauna in terms of natural fish productivity in the forage base in the considered zone indicate the possibility of achieving fish productivity at the level of 400–500 kg/ha during the seasonal period of pond fish cultivation, which is a higher indicator in comparison with the available data for Penza region and data on reservoirs of neighboring regions.

Excess harvesting power can threaten the long-term sustainability of fisheries. Indicators of excess harvesting capacity must include input–output-based estimates of economic production efficiency. The increasing use of drifting Fish-Aggregating-Devices (DFADs) has boosted fishing productivity in high-seas tuna fisheries, perhaps beyond the biological capacity of the stocks, and is an object of global debate. We carried out a Data Envelopment Analysis (DEA) of relative changes in production efficiencies of the French purse-seine fleet targeting tropical tuna in the western Indian Ocean using two fishing strategies: (1) on floating objects (FOB) and (2) free swimming schools (FSC) using tuna catch and effort data spanning 1992–2019. We show that FOB fishing evolved dramatically through time with an estimated change of 3.6%yr−1 (8.0%yr−1 2007–2019), in contrast to 2.1%yr−1 for FSC. While the efficiency level in combining and using inputs has barely changed for FOB fishing, it means that all the growth in productivity comes from technical change for this strategy. The dynamics is different for the FSC with a mixture of innovation and higher efficiency. Immediate plans to improve input-based management in this region are needed to prevent further risks of overfishing to yellowfin (Thunnus albacares) and skipjack (Katsuwonus pelamis) tunas. [ABSTRACT FROM AUTHOR]

The Celtic Seas ecoregion (CSE) is undergoing climatic and ecosystem changes, which can induce changes in fish productivity. Globally, the productivity of many stocks has shown evidence of change over decadal timescales. Varying factors might drive these dynamics in the CSE, but for many stocks, these mechanisms have not been fully understood to be included in management advice. We study dynamic productivity for 28 stocks in the Celtic Seas by tracking integrated stochastic signals in the relationship between stock size and recruitment using state-space modelling applying Peterman's Productivity Method. Our research objectives were to (i) fit Ricker stock–recruitment models with time-varying parameters to all age- or length-based assessed stocks in the CSE, (ii) evaluate which parameters vary in time, (iii) examine temporal characteristics of historical recruitment productivity, and (iv) evaluate productivity correlation across stocks. For 22 out of 28 stocks, at least one of the three time-varying parameter models had a better fit than the time-invariant model. In the CSE, fish productivity has diverse temporal patterns, with some stocks displaying relevant long-term decreasing productivity trends. Getting insight into temporal changes in recruitment productivity is very valuable and has important implications for sustainable fisheries. [ABSTRACT FROM AUTHOR]

Globally, small temporarily closed estuaries are the least considered for fisheries assessment and management due to a low scientific priority and regional importance. However, these ecosystems are highly exposed to anthropogenic pressures and may deteriorate without assessing its aquatic resources. In this study, fish diversity and guild structure of Chettuva—a temporarily closed tropical estuary in the western coast of India—was investigated. A total of 70 fish taxa belonging to 32 families were recorded with the quantitative predominance of families; Mugilidae, Cichlidae, and Leiognathidae. Family Carangidae had the highest species diversity (seven species), followed by Clupeidae and Mugilidae (five species). Ecological guild assessment revealed that the immigrating marine fish species (marine estuarine opportunist (34 species) and marine estuarine dependent (13 species)) dominated the guild structure over the estuarine resident species (seven species). The marine species were found all along the saline gradient and throughout the sampling period indicating the salinity ingress towards the estuarine zone throughout the year. Carnivores and omnivores were the major feeding mode functional guilds in terms of diversity, whereas detritivores dominated in numerical abundance throughout the salinity gradient. The major environmental drivers of the fish assemblages in the estuary were salinity and chlorophyll a. The distribution of freshwater fishes and estuarine resident species was connected with the rising primary productivity as the majority of fishes rely on the algae for feeding, whereas marine estuarine dependent and marine estuarine opportunist species occurred in areas with the highest salinity concentrations. [ABSTRACT FROM AUTHOR]

Nile tilapia is known for its relative tolerance to some biotic and abiotic stressors. However, long-period water exchange may impair the health status and, thereby, the growth performance and feed utilization. In this regard, using herbal extracts may help to relieve the adverse impacts of low water quality on the productivity of this fish species. A 100-day feeding trial was designed to examine the effects of dietary supplements of Aloe vera leaves (AVE), and chamomile flowers, Matricaria chamomilla (CFE) extracts on water quality, growth performance, and well-being of Nile tilapia. Fish (3.95±0.05 g, n=1200) were distributed into five groups (15 fiberglass tanks, 2 m3) under a water exchange rate of 20% every two days for standard control (T0) without herbal supplements. Groups (T1, T2, T3, and T4) were exposed to a long water exchange period of 50% every month, wherein T1 (stressed control), T2, T3, and T4 groups were fed a diet supplemented with 0% herbal extract, 1% AVE, 1% CFE and 0.5% AVE +0.5% CFE, respectively. Results showed that feeding on a T2 diet exhibited a clear improvement under a long period of water exchange stress, and it is almost similar to their counterparts under normal conditions (T0) in terms of specific growth rate, survival rate, feed intake, feed conversion ratio, and protein efficiency ratio. Moreover, the lowest levels of aspartate aminotransferase were obtained with T2 and T0. In addition, the highest white blood cell count and hemoglobin values were recorded with group T0, followed by T2, and T4, while there was no significant difference between T3 and T1. Fish under stressed conditions without herbal extracts (T1) showed the lowest performance and survival rate compared to T0 and T2 groups. In conclusion, feeding diet supplied with 1% A. vera extract to stressed fish restored their performance and well-being to the level of their counterparts under normal conditions. [ABSTRACT FROM AUTHOR]

Parasites constitute a major problem for fish health and their prevalence hamper fish growth and productivity by increasing their morbidity and mortality. Fish endoparasites are often associated with zoonotic disease in humans. The aim of this study was to determine the endoparasitic prevalence and feeding habits of Oreochromis aureus, Amia calva and Clarias gariepinus, in Ase River, Delta State, Nigeria. A total of 104 fish comprising of 40 O. aureus, 21 A. calva and 43 C. gariepinus were collected from seven locations of the river during dry and wet seasons, for parasitological investigations. The livers, gills, muscles, small and large intestines of fish specimens were examined, and the sex determination was done by physical observation of the genital papilla, which appeared long in males and reddish round in females. From the specimens, 96 (92.3%) had 191 overall endoparasitic loads. The highest and lowest percentage abundance of 51.18% and 13.08% were recorded in Locations 1 and 4 had respectively. Of the 96 infected fish, 29 (29.8%) were male and 68 (70.1%) female, indicating a much higher infection rate in females. On prevalence abundance across species, A. calva was highest with 21(100%). C. gariepinus was 40 (93.0%) and O. aureus was least with 35(87.5%). The study also identified a total of 21 endoparasites in five taxonomic groups; Protozoans (32.46%), Nematode (38.74%), Annelid (3.66%), Trematode (15.70%) and Cestode (9.42%). The mean intensity of parasitic load showed 58.6, 37.0 and 31.6 to be moderately, highly and slightly affected. ANOVA result on prevalence indicated a significant distribution of endoparasites across specimens (P<0.05; P=0.001). Considering the effect of parasites on fish morbidity and mortality, human food-borne zoonoses, there is need for the communities and industries on the riverbank to adopt right policies for water pollution control. [ABSTRACT FROM AUTHOR]

Cebong Lake is one of several lakes in Indonesia located in Sembungan Village and formed by volcanic activities from the Dieng plateau, Wonosobo. Cebong Lake is heavily used by local communities for irrigation, tourism, and the local community’s needs. Water usage will have an impact on lake productivity and fish production. This study aims to determine the environmental changes in Cebong Lake that may have occurred in the past by analyzing the structure community of diatom that composes vertically using 5-65 cm samples sediment of Cebong Lake (interval 5 cm, 13 samples). Methods used for sample treatment include: preparation, digestion, identification of diatom, and enumeration. The result obtained are analyzed using the relative abundance and ecosystem indices. The result found 171 species of diatom belonging to 41 genera, total diatom abundance is 702.975 ind.gr, Diversity index value (H’) ranges between 3.10-3.80, Evenness index value (E) ranges between 0.42-0.70, Dominance index value (D) ranges between 0.03-0.09. Based on Bray-Curtis analysis, Cebong Lake is divided into 2 zones, namely: zone 1 (40-65 cm layers) describes as oligo-mesotrophic waters, and zone 2 (5-35 cm layer) describes as meso-eutrophic waters. [ABSTRACT FROM AUTHOR]

To understand the community structure of zooplankton and assess the survivability of the Yangtze finless porpoise (YFP), a field investigation of seasonal variation of zooplankton and environmental parameters was conducted in the Nanjing Yangtze Dolphin Nature Reserve (NYDNR) from October 2021 to August 2022. The results showed that: (1) a total of 54 species were identified, and the number of species belonging to protozoa, rotifer, cladocera, and copepods was 19, 12, 11 and 12, respectively; (2) the total zooplankton density was 21571.65 ind./L, dominated by protozoa (89.7%), and the total biomass was 6.6762 mg/L, dominated by rotifer (28.0%) and copepods (48.2%); (3) the assessment results of water quality showed that the NYDNR was classified as mesotrophic level, it was indicated that the water quality of the NYDNR satisfied the living requirement for YFP; (4) the fish productivity in the NYDNR is about 43139.34 kg, which could meet the nutrition requirements of 28 YFPs, and fish potential productivity estimation through zooplankton showed that food sources of YFP were being threatened. The results of this study not only improved the understanding of the community structure of zooplankton, but also have important implication to the protection of YFP in the NYDNR. [ABSTRACT FROM AUTHOR]

Aquaponics (AP) and biofloc technology (BFT) systems rely heavily on bacterial communities to break down organic matter and cycle nutrients that are essential for fish and plant growth. The functional roles of bacterial communities in aquaculture systems are critical to their sustainable operation. Currently, the research on the combination of BFT and AP systems called FLOCponics (FP) is lacking, thereby hindering our ability to optimize their performance. Here, several characteristics (productivity of fish and crops, physicochemical properties of water, and bacterial community) in FP systems cultivating Japanese eel (Anguilla japonica) and leaf lettuce Caipira (Lactuca sativa) were compared to those in the BFT system. Additionally, the effect of fish density on the FP system was investigated. The results indicated that the FP system was more productive than the BFT system. Fish growth rate was highest in the FP system (52.6%), and the average body weight of eels was 168.2 ± 26.8 g in the FP system compared to 140.3 ± 27.0 g in the control (BFT, 5 kg/m2). However, increasing fish density resulted in lower growth rates, with a growth rate of 20.6% observed in the high-density (20 kg/m2) experimental group. The bacterial composition was also significantly different between the systems and fish densities, suggesting that bacterial communities may be closely related to the performance of the aquaponics system. [ABSTRACT FROM AUTHOR]

Local communities' perception on how ecosystems such as mangroves contribute to their resilience to climate change is essential to effectively engage them in adaptation and mitigation actions. This study assessed the perceptions of coastal communities on climate change, and the contribution of mangroves in their resilience to climate change in the southern Côte d'Ivoire. Individual interviews (n = 120) were conducted in four coastal villages, selected based on their proximity to mangroves. Data were analyzed using the Chi-Square test simple correspondence analysis. Informants' knowledge on climate change was low. However, the scarcity of rainfall (62%), increased temperature (heat) (32%), and the high frequency of high winds (6%) have been cited as indicators of changes in the climate. More than half of respondents (63.3%) agreed that mangroves help people adapt to climate change because they produce more fish, shield people from poverty, and lessen flooding, storms, and erosion in their communities. This study has demonstrated a substantial relationship between the level of mangrove significance knowledge and the profession practiced in terms of whether it is affected by climate change. People with higher levels of education and members of particular professions frequently know more about climate change. The profession is a key driver in the knowledge of the contribution of mangroves in protecting fish fauna against climate change. Mangroves reduce the vulnerability of coastal communities to the effects of climate change through their ecosystem services which include fish productivity (which provides income to fishermen and fish sellers as well as alternative income to farmers), protection against flooding and erosion, and more. Therefore, it is of utmost importance to conserve this ecosystem at all costs. [ABSTRACT FROM AUTHOR]

In recent time lakes are deteriorated by twincongenital and anthropogenic exercises. Generally, lakes bring off the activities precisely interrelated to their substantial, alchemical and organicprobity to conclude thecondition of water. The objective of the study is to develop the freedom of water and fishes from the Lake. Variousrheological parameters such as pH(MPH), Electrical Conductivity (MEC), Dissolved Oxygen (MDO), Total Alkalinity (MTA), Total Hardness (MTH), Chloride (MCL), Nitrates (MN), Phosphate (MP), Turbidity(MTB) and Total Dissolved Solids (MTDS) of lake water isinspected during the month of June. The result shows that due to some parameters Mohabala lake water is not suitable for the freeness of fishes. Hence some special appraisal needed for the cultivation of fishes. [ABSTRACT FROM AUTHOR]