Freshwater Ponds Research Articles

A review of the benefits and limitations of waste nutrient treatment in aquaculture pond facilities

AbstractManaging waste nutrients from intensive freshwater and marine pond aquaculture is a global challenge. Nutrient‐enriched water released from farms can have detrimental effects on aquatic ecosystem health. There are a range of treatment options for discharge water from fish and crustacean ponds, and this review examines the benefits and limitations of these options. Much of the nutrient waste is derived from the addition of formulated feed. In recent years, reduction in waste from feeds and feeding has been largely incremental. In terms of treatment, there are low‐cost approaches, such as settlement ponds, but they are inefficient at reducing nutrients. Biological systems, using aquatic plants, microalgae and filter feeders to reduce nutrient release from farms have variable levels of effectiveness. Establishing wetlands requires considerable additional land area, and success to date has been highly variable. Overall, this review found no simple cost‐effective solution for managing nutrient enriched water from ponds. This is due, in many cases, to challenges with treating the large volumes of discharge water with relatively low nutrient concentrations. This means that more technologically advanced and reliable treatment options, for example, bioreactors, are prohibitively expensive. However, some systems, such as use of recirculation systems typically increase nutrient concentrations, and hence the efficiency and effectiveness of more expensive treatment methods. Biofloc systems can also provide a mechanism for in‐situ nutrient treatment as well as a supplementary food source for animals. Overall, there is scope to improve treatment of waste nutrients, but significant modifications to many production systems are needed to achieve this.

Monogamous hybridization of Nile tilapia (Oreochromis niloticus) with Mozambique tilapia (O. mossambicus) results in unprecedented all-female F1 hybrid

Tilapiine breeding success is season-dependent, with very rare exceptions. The female (f) to male (m) ratio differences showed significant variations in fruitful breeding. Furthermore, the female-to-male ratio in any hybridization protocol involving reciprocal crosses may be the most influential factor in determining breeding seasonality. The innate genetic traits of tilapia, a prominent contributor to global aquaculture production, enable them to easily adapt to a wide range of aquatic environments, rendering them suitable for domestication. The study aimed to determine the breeding timeframe of Nile tilapia (Oreochromis niloticus, N) through interspecific monogamous/two-parent reciprocal crossing with Mozambique tilapia (O. mossambicus, M). Considering preselected genotypic characteristics by PrlLK microsatellite marker, different combinations of hybrid reciprocal crosses were performed in breeding hapa (3 × 3 × 3 cubic feet) inside an indoor plastered cemented tank and then in an outdoor earthen pond facility. Total 11 parental pairs were attempted to propagate inside a cemented tank with (9 pairs) and without (2 pairs) hapa during early April to mid-June. Unfortunately, the trials failed to produce any successful breeding within the schedule. Among those 11 pairs, 6 pairs were Nf × Mm and 5 pairs were Mf × Nm cross. In the earthen pond inside hapa, a total of 18 pairs were attempted where seven breeding successes were reported without demonstrating any dependency for hybridizations over cross types or genotypes and for individuals over sex or species. Successful breeding were reported from the month of May to November. There were few overlapping months of successful breeding for different grouping categories. During the successful breeding period, there were no successful outcomes in both August and October. An inadvertent all-female F1 generation was observed for Mf × Nm crosses, while the reciprocal cross Nf × Mm produced an F1 generation with a nearly 1:1 female to male ratio. The F1 sex ratios exhibited a significant reliance on parental genotypic combinations (p = 5.4e-11). The success stories from different cross combinations would help to frame the breeding protocol for future research. More precisely, for arranging a breeding schedule in freshwater earthen ponds inside hapa for a monogamous/two-parent hybrid cross the study light a close insight.

Chronic Toxicity of Microplastics on Fish (Labeo rohita) and Their Impact on the Freshwater Ecosystem: A Case Study of Gangasagar Pond, Darbhanga, India

The present investigation was conducted to evaluate the chronic toxicity of microplastics on fish, Labeo rohita and isolation, identifications and estimation of microplastics in freshwater pond, Gangasagar Pond, Darbhasnga. traceable clinical, anatomical (morphological) and histopathological alterations. The data were analyzed and found that microplastic fibre (ranging between 12 to 56/m3) were dominated followed by microplastic film (ranging between 10 to 38), fragment (ranging between 8-22). The number of foam, beads (spherical) and coloured were relatively low. The sources of these plastic contaminations are mainly domestic wastes, discarded packaging materials and medical wastes. Trace of microplastics in gill chamber as well as buccal cavity was well marked causing edematous changes. The Histopathological studies suggest that intestine and stomach were the most affected organs in response to microplastics abuse. Microplastics will ultimately affect the aquatic fauna of the pond adversely.

Paucibacter sediminis sp. nov., isolated from sediment in a freshwater pond.

A Gram-stain-negative, aerobic, oxidase-positive, weakly catalase-positive, motile by means of a single polar flagellum, rod-shaped bacterium designated as strain S2-9T was isolated from sediment sampled in Wiyang pond, Republic of Korea. Growth of this strain was observed at 10-40 °C (optimum, 35 °C) and pH 5.5-9.5 (optimum, pH 7.0-8.0) and in the presence of 0-0.5 % NaCl in Reasoner's 2A broth. The major fatty acids (>10 %) of strain S2-9T were C16 : 0 and summed feature 3 (comprising a mixture of C16 : 1 ω7c and/or C16 : 1 ω6c). Ubiquinone-8 was detected as the respiratory quinone. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. Strain S2-9T showed the highest 16S rRNA gene sequence similarity to Paucibacter oligotrophus CHU3T (98.7 %), followed by 'Paucibacter aquatile' CR182 (98.4 %), all type strains of Pelomonas species (98.1-98.3 %), Mitsuaria chitosanitabida NBRC 102408T (97.9 %), Kinneretia asaccharophila KIN192T (97.8 %), Mitsuaria chitinivorans HWN-4T (97.4 %), and Paucibacter toxinivorans 2C20T (97.4 %). Phylogenetic trees based on the 16S rRNA gene and whole-genome sequences showed that strain S2-9T formed a tight phylogenetic lineage with Paucibacter species (CHU3T, CR182, and 2C20T). Average nucleotide identity and digital DNA-DNA hybridization values between strain S2-9T and Paucibacter strains were 76.6-79.3% and 19.5-21.5 %, respectively. The genomic DNA G+C content of strain S2-9T was 68.3 mol%. Notably, genes responsible for both sulphur oxidation and reduction and denitrification were found in the genome of strain S2-9T, suggesting that strain S2-9T is involved in the nitrogen and sulphur cycles in pond ecosystems. Based on the polyphasic taxonomic results, strain S2-9T represents a novel species of the genus Paucibacter, for which the name Paucibacter sediminis sp. nov. is proposed. The type strain is S2-9T (= KACC 22267T= JCM 34541T).

Human-driven fire and vegetation dynamics on the Caribbean island of Barbuda from early indigenous to modern times

We present a multiproxy analysis of a sediment core from Freshwater Pond, Barbuda, one of just a few inland paleoenvironmental records from the Lesser Antilles. Our results shed light on the relative contributions of climate variability and Pre- and Post-Columbian human activities to vegetation and fire dynamics on Barbuda. The presence of macroscopic charcoal and pollen of ethnobotanically-useful and disturbance-indicator plant taxa in the sediment record suggests that Pre-Columbian subsistence activities occurred within a few kilometers of the pond between ~150 BCE and ~1250 CE. Our record extends anthropogenic fires back into the early Ceramic (500 BCE–1500 CE) and possibly late Archaic Ages (3000–500 BCE) adding evidence to the timing of arrival of the island’s earliest inhabitants. The history of island-wide biomass burning inferred from microscopic charcoal fragments showed heightened fire activity between ~540 and ~1610 CE followed by a period of quiescence that reflected the transition from Pre- to Post-Columbian land-use practices associated with European colonization of the region. The British established a permanent settlement on Barbuda in the 1660s, but given Barbuda’s unsuitability for large-scale agriculture, timber harvesting, small-scale farming, and livestock rearing, activities that left no detectable charcoal footprints likely dominated post-colonial land use. The lack of any clear correspondence between the reconstructed histories of fire and effective moisture at Freshwater Pond supports the idea that Late-Holocene fire activity on Barbuda was driven primarily by human activity.

Taxonomic relationship does not limit dietary assemblages in fish: an investigation in small freshwater fishes

Abstract Foraging profitability is one of the significant factors affecting habitat selection in fishes. The food habits of the fish species vary seasonally due to the dynamic nature of their environment. For that, the dietary analysis of a fish is essential in the case of fish diversity research. Most of the variations in prey size consumed by piscivores were correlated to the differences in piscivore body size, which morphological constraints can explain. The present study aimed to investigate the ecomorphological assemblage of small indigenous freshwater fish species from smaller lentic freshwater bodies based on a range of morphological traits and evaluate fish assemblages with respect to the feeding guilds. Freshwater ponds around Birbhum district, West Bengal (India) were selected for the collection of fish species, namely Amblypharyngodon mola, Puntius sophore, Esomus danrica, Lepidocephalichthys guntea, Chanda nama, Parambassis lala, Trichogaster fasciata, Anabas testudineus and Glossogobius giuris. Morphometric and gut content analysis were done, and the trophic guild matrix, taxonomic distance matrix, and morphological matrix were calculated. The result showed a strong association between ecomorphological traits and trophic structure, indicating an independent assemblage pattern beyond the taxonomic influence.

Methane Emissions From the Qinghai‐Tibet Plateau Ponds and Lakes: Roles of Ice Thaw and Vegetation Zone

AbstractComprehensive seasonal observation is essential for accurately quantifying methane (CH4) emissions from ponds and lakes in permafrost regions. Although CH4 emissions during ice thaw are important and highly variable in high‐latitude freshwater ponds and lakes (north of ∼50°N), their contribution is seldom included in estimates of aquatic‐atmospheric CH4 exchange across different alpine ecosystems. Here, we characterized annual CH4 emissions, including emissions during ice thaw, from ponds and lakes across four alpine vegetation zones in the Qinghai‐Tibet Plateau (QTP) permafrost region. We observed significant spatial variability in annual CH4 emission rates (8.44−421.05 mmol m−2 yr−1), CH4 emission rates during ice thaw (0.26−144.39 mmol m−2 yr−1), and the contribution of CH4 emissions during ice thaw to annual emissions (3−33%) across different vegetation zones. Dissolved oxygen concentration under ice, along with substrate availability and water salinity, played critical roles in influencing CH4 flux during ice thaw. We estimated annual CH4 emissions from ponds and lakes in the QTP permafrost region as 0.04 (0.03−0.05) Tg CH4 yr−1 (median (first quartile−third quartile)), with approximately 20% occurring during ice thaw. Notably, the average areal CH4 emission rate from ponds and lakes in the QTP permafrost region amounts to only 8% of that from high‐latitude waterbodies, primarily due to the dominance of large saline lakes with lower CH4 emission rates in the alpine permafrost region. Our findings emphasize the significance of incorporating comprehensive seasonal observation of CH4 emissions across different vegetation zones in better predicting CH4 emissions from alpine ponds and lakes.

The possibilities of using of captive and domestic broodstocks for saving of natural populations: 1. Acipenseriformes (part 1)

In last years the stocks of Russian species of sturgeons decreased to critical level which can be followed by their complete extinction in nature. As a result, the number of sturgeons beginning spawning migration into rivers are extremely small, but Astrakhan sturgeon hatcheries continue release annually about 35 mln fry using own broodstocks of two types — captive and domestic ones. However the releases of offspring of domestic broodstock are extremely discussible. On one hand, creation of such broodstocks could avoid the complete extinction of natural populations of Adriatic sturgeon Acipenser naccari in Po River and European sturgeon A. sturio in Gironde estuary. On other hand, long-term practice of commercial fish farming had shown that even the accidental refugees from sea cages or fresh-water ponds caused great harm to natural populations of same species. Hatchery individuals were undergoing different selection than fish in wild nature and had poorly formed reflexes (searching for food and avoiding predators). Besides a progressive decrease in genetic diversity with each generation could be seen in such fry due to limited number of parents (the Ryman-Laikre effect). However the creation of captive and domestic broodstocks of endangerous species and subspecies (Azov beluga Huso huso maeotica, fringebarbel sturgeon Acipenser nudiventris, Sakhalin sturgeon Acipenser mikadoi) and extinct populations (Baltic sturgeon Acipenser oxyrinchus) remains the only way to release hatchery juveniles. The first part of presented review is devoted to creation and using of captive and domestic broodstocks for conservation-type sturgeon fry releases in Russia and other countries.

The possibilities of using of captive and domestic broodstocks for saving of natural populations: 1. Acipenseriformes (part 2)

In last years the stocks of Russian species of sturgeons decreased to critical level which can be followed by their complete extinction in nature. As a result, the number of sturgeons beginning spawning migration into rivers are extremely small, but Astrakhan sturgeon hatcheries continue release annually about 35 mln fry using own broodstocks of two types — captive and domestic ones. However the releases of offspring of domestic broodstock are extremely discussible. On one hand, creation of such broodstocks could avoid the complete extinction of natural populations of Adriatic sturgeon Acipenser naccari in Po River and European sturgeon A.sturio in Gironde estuary. On other hand, long-term practice of commercial fish farming had shown that even the accidental refugees from sea cages or fresh-water ponds caused great harm to natural populations of same species. Hatchery individuals were undergoing different selection than fish in wild nature and had poorly formed reflexes (searching for food and avoiding predators). Besides a progressive decrease in genetic diversity with each generation could be seen in such fry due to limited number of parents (the Ryman-Laikre effect). However the creation of captive and domestic broodstocks of endangerous species and subspecies (Azov beluga Huso huso maeotica, fringebarbel sturgeon Acipenser nudiventris, Sakhalin sturgeon Acipenser mikadoi) and extinct populations (Baltic sturgeon Acipenser oxyrinchus) remains the only way to release hatchery juveniles. The first part of presented review is devoted to creation and using of captive and domestic broodstocks for conservation-type sturgeon fry releases in Russia and other countries.

Satellite imagery as a management tool for monitoring water clarity across freshwater ponds on Cape Cod, Massachusetts

Water clarity serves as both an indicator and a regulator of biological function in aquatic systems. Large-scale, consistent water clarity monitoring is needed for informed decision-making. Inland freshwater ponds and lakes across Cape Cod, a 100-km peninsula in Massachusetts, are of particular interest for water clarity monitoring. Secchi disk depth (SDD), a common measure of water clarity, has been measured intermittently for over 200 Cape Cod ponds since 2001. Field-measured SDD data were used to estimate SDD from satellite data, leveraging the NASA/USGS Landsat Program and Copernicus Sentinel-2 mission, spanning 1984 to 2022. Random forest machine learning models were generated to estimate SDD from satellite reflectance data and maximum pond depth. Spearman rank correlations (rs) were “strong” for Landsat 5 and 7 (rs = 0.78 and 0.79), and “very strong” for Landsat 8, 9, and Sentinel-2 (rs = 0.83, 0.86, and 0.80). Mean absolute error also indicated strong predictive capacity, ranging from 0.65 to 1.05 m, while average bias ranged from −0.20 to 0.06 m. Long- and recent short-term changes in satellite-estimated SDD were assessed for 193 ponds, selected based on surface area and the availability of maximum pond depth data. Long-term changes between 1984 and 2022 established a retrospective baseline using the Mann-Kendall test for trend and Theil-Sen slope. Generally, long-term water clarity improved across the Cape; 149 ponds indicated increasing water clarity, and 8 indicated deteriorating water clarity. Recent short-term changes between 2021 and 2022 identified ponds that may benefit from targeted management efforts using the Mann-Whitney U test. Between 2021 and 2022, 96 ponds indicated deteriorations in water clarity, and no ponds improved in water clarity. While the 193 ponds analyzed here constitute only one quarter of Cape Cod ponds, they represent 85% of its freshwater surface area, providing the most spatially and temporally comprehensive assessment of Cape Cod ponds to date. Efforts are focused on Cape Cod, but can be applied to other areas given the availability of local field data. This study defines a framework for monitoring and assessing change in satellite-estimated SDD, which is important for both local and regional management and resource prioritization.

Revision of Lower Devonian clam shrimp (Branchiopoda, Diplostraca) from the Rhenish Massif (Eifel, SW-Germany), and the early colonization of non-marine palaeoenvironments

Three collections of clam shrimp from the Lower Devonian (upper lower Emsian) Klerf Formation of Willwerath and Waxweiler in the western Eifel Mountains are herein studied. Four discernible morphotypes are present in the Willwerath assemblage. These morphotypes correspond to the previously described species from this locality: Pseudestheria diensti (Gross), Pseudestheria subcircularis Raymond, and Palaeolimnadiopsis? eifelensis Raymond. The fourth morphotype also closely corresponds to Pseudestheria diensti, but is slightly different in outline. Asmussia willweratica (Novozhilov) is an objective synonym of Pseudestheria subcircularis. In the Willwerath clam shrimp sample, it is difficult to disentangle taphonomic/preservational versus ontogenetic/sexual variation. If taphonomic/preservational causes could be confirmed, all the Willwerath specimens may represent just one taxon and Pseudestheria subcircularis and Palaeolimnadiopsis? eifelensis would be potential subjective synonyms of Pseudestheria diensti. However, we refrain from a formal taxonomic act, which requires a larger number of specimens to be analysed.In addition, we investigated two samples from Waxweiler, which originate from distinct centimetre-thick layers and therefore represent associations. One of these associations comprises two discernible clam shrimp morphotypes. Because of limited preservation of morphological characters, one is here left in open nomenclature as Spinicaudata incertae sedis, whereas the other is recognised as a new species of the family Palaeolimnadiopseidae, Palaeolimnadiopsis frankeorum sp. nov. The second association from Waxweiler comprises at least four, possibly six different clam shrimp taxa. In addition to Pseudestheria diensti, Palaeolimnadiopsis sp., and poorly preserved Asmussia- and Ulugkemia-like specimens, two taxa can be described as new, namely the vertexiid Cornia wasvilrensis sp. nov. and the leaiine Eicheleaia wenndorfi gen. nov. et sp. nov. Altogether, the Klerf Formation at Waxweiler yields a total of at least five (possibly eight) clam shrimp taxa. The palaeoenvironment of these early clam shrimp from the Klerf Formation is interpreted as a non-marine, relatively proximal deltaic setting with no or very minor marine influence, such as a deltaic freshwater pond or lake. The comparatively high diversity of these lower Devonian clam shrimp suggests a considerably earlier origin and cryptic evolution of the group.

A Review on Freshwater Pond Fish Farming in Cambodia

A Review on Freshwater Pond Fish Farming in Cambodia

Algal communities in urban freshwater ponds: prospects for biodiesel production

Algal communities in urban freshwater ponds: prospects for biodiesel production

Fictibacillus fluitans sp. nov., isolated from freshwater pond.

A Gram-positive, aerobic, rod-shaped, spore-forming bacterium, designated NE201T, was isolated from a freshwater pond in Village Nerur, India. Growth was observed in the range of 15-45°C temperature with optimum at 30°C, pH range of 5-9 (optimum at 7.0), and at concentrations of NaCl ranging between 0 and 14% (optimum 0%, w/v). The 16S rRNA gene sequence showed the highest similarity with Fictibacillus enclensis NIO-1003T (JF893461) at 99.01% followed by F. rigui WPCB074T (EU939689) at 98.9% and F. solisalsi CGMCC 1.6854T (EU046268) at 98.66%. The digital DNA-DNA hybridization (dDDH) and orthoANI values for strain NE201T against F. enclensis NIO-1003T (GCA_900094955.1) were 33.7% and 87.68%, respectively. The phylogenetic analysis based on the 16S rRNA gene, 92 core genes derived from the genome, and 20 proteins involving over 20,236 amino acid positions revealed the distinct phylogenetic position of strain NE201T and the formation of a clearly defined monophyletic clade with F. enclensis. The strain NE201T showed a unique carbon utilization and assimilation pattern that differentiated it from F. enclensis NIO-1003T. The major fatty acids were anteiso -C15:0 (51.42%) and iso-C15:0 (18.88%). The major polar lipids were phosphatidylglycerol (PG), phosphatidylethanolamine (PE, and diphosphatidylglycerol (DPG). The antiSMASH analyzed genome of NE201T highlighted its diverse biosynthetic potential, unveiling regions associated with terpene, non-ribosomal peptide synthetases (NRPS), lassopeptides, NI-siderophores, lanthipeptides (LAP), and Type 3 Polyketide Synthases (T3PKS). The overall phenotypic, genotypic, and chemotaxonomic characters strongly suggested that the strain NE201T represents a novel species of genus Fictibacillus for which the name Fictibacillus fluitans sp. nov. is proposed. The type strain is NE201T(= MCC 5285 = JCM 36474).

Understanding the differential impacts of two antidepressants on locomotion of freshwater snails (Lymnaea stagnalis)

There is growing evidence of negative impacts of antidepressants on behavior of aquatic non-target organisms. Accurate environmental risk assessment requires an understanding of whether antidepressants with similar modes of action have consistent negative impacts. Here, we tested the effect of acute exposure to two antidepressants, fluoxetine and venlafaxine (0–50 µg/L), on the behavior of non-target organism, i.e., freshwater pond snail, Lymnaea stagnalis. As compounds interact with chemical cues in the aquatic ecosystems, we also tested whether the effects altered in the presence of bile extract containing 5α-cyprinol sulfate (5α-CPS), a characterized kairomone of a natural predator, common carp (Cyprinus carpio). Behavior was studied using automated tracking and analysis of various locomotion parameters of L. stagnalis. Our results suggest that there are differences in the effects on locomotion upon exposure to venlafaxine and fluoxetine. We found strong evidence for a non-monotonic dose response on venlafaxine exposure, whereas fluoxetine only showed weak evidence of altered locomotion for a specific concentration. Combined exposure to compounds and 5α-CPS reduced the intensity of effects observed in the absence of 5α-CPS, possibly due to reduced bioavailability of the compounds. The results highlight the need for acknowledging different mechanisms of action among antidepressants while investigating their environmental risks. In addition, our results underline the importance of reporting non-significant effects and acknowledging individual variation in behavior for environmental risk assessment.Graphical

Hardware Realization of Long Range (LoRa) Based Telemetry System for Aquaculture Monitoring

Freshwater fish farming must pay attention to the condition of the water content in the pond and the water quality in the pond. Fish will feel comfortable if the efficiency of oxygen levels and pond water content is maintained. Freshwater fish farming needs to optimize crop yields so as not to get losses. The problem that is often encountered is that many fish die in the pond due to lack of water. Irrigation channels leading to fishponds experience blockages. The smoothness of the irrigation channel affects the volume of water in the pond. Blockage of irrigation channels is usually due to garbage trapped in irrigation, causing dirty water to settle and water sequestration to occur in the pond. This tool system aims to improve water quality and increase the efficiency of oxygen levels by using TDS and ultrasonic sensors. The parameter value on the sensor affects the work of the tool actuator. The tool actuator is a water pump that is used as a substitute for irrigation channels and an aerator motor to increase dissolved oxygen in water by moving the propeller on the surface of the pond water. Wireless technology is used for data communication. Because the land of freshwater fish farming ponds is a large area and is far from settlements, wireless communication is suitable for enabling easy and fast access to information and services. In this research, the testing methods used are functional testing and system performance testing. Functional testing is used to prove whether the system that has been implemented can meet the requirements of operational functions as planned. System performance testing is intended to monitor several parameters that can show the ability and reliability of the system in carrying out its operational functions. The result of the overall test is the LoRa communication distance that can communicate up to about 1000 meters, proving that LoRa technology has a strong enough ability in terms of range wireless communication. The PLE (Path Loss Exponent) of the LoRa module with 100 meters in LoS (indoor) conditions is 7.77, while in nLoS conditions in obstructed in-building, it is 10.13. The average error of the ultrasonic sensor type JSN SR-04T is 0.16% and has a difference of ± 1 cm. The TDS sensor with dissolved pool water content has an average value of 142.6 ppm with an error value of 1.05%. The PDAM water content has an average value of 112.1 ppm with a sensor value of 1.38%. The water content of the lime and detergent mixture has the highest observed ppm value, which is an average of 737.33 ppm, with a sensor error of 0.14%. The water pump activates when the pool water is low (when the ultrasonic distance reaches 60 cm), and the aerator activates when the water content is contaminated (when the TDS sensor value exceeds 500 ppm).

Water–Salt Migration Patterns among Cropland–Wasteland–Fishponds in the River-Loop Irrigation Area

In order to investigate the influence of freshwater fish ponds on water and salt transport in cultivated wasteland in salinized areas, a typical study area was selected in the middle and lower reaches of the Hetao Irrigation District in China in the Yichang Irrigation Domain, and the temporal and spatial changes in the salinity of soil and salinity of groundwater and fish pond water in the cultivated–wasteland–fish pond system were characterized through the monitoring of the environmental information of soil and groundwater at the boundaries of the cultivated land, wasteland, and fish ponds. Salinity changes and groundwater migration in different periods were determined, and the response of soil salinity to the depth of groundwater burial was analyzed, as well as the effect of fish ponds on soil salinization. The results showed that the amount of groundwater migrating from cropland to wasteland during the simulation period in 2022 was 2700 m3, the amount of groundwater migrating from wasteland to fish ponds was 630 m3, and the amount of groundwater migrating from fish ponds to wasteland during the fall watering period was 440 m3. From an overall perspective, the average soil salinity of wasteland was 1.56 times higher than that of the boundary of fish ponds. Not only do fish ponds play a positive role in the ecosystem, but they also have a desalinization effect that reduces soil salinity significantly. Groundwater depth and soil salinity have an exponential relationship; when the depth of groundwater is greater than 1.75 m, the soil salinity varies little with the depth of groundwater and the soil salinity is less than 0.66 ds/m, which can be determined as the critical depth, and the average depth of groundwater in cultivated land in the study area is 1.5 m. Therefore, it is necessary to reasonably control the water level of fish ponds, so as to make the groundwater depth of cultivated land control between 1.75 m and 2.0 m, and to prevent soil salinization.

Effect of feed enriched with fermented coconut water products on growth and carcass composition of gurami sago (Osphronemus goramy Lacepède, 1801) juvenile.

Background Giant gourami (Osphronemus goramy Lacepede, 1801) is a popular freshwater species in Indonesia, but there is limited information on feed used for its cultivation. Therefore, this study aims to determine effect of feed enriched with fermented coconut water and palm sap sugar solution on growth, feed efficiency, and carcass composition of juvenile sago gurami. Methods A total of 2 litres coconut water and 1litres palm sap sugar solution (10%) were formulated. Each formulated product was then mixed with 6 g Aspergillus niger (P1), 6 g Rhizopus oligosporus (P2), and 6 g Saccharomyces cerevisiae (P3) to obtain the supplements. Subsequently, supplementation was carried out on commercial feed at a dose of 300 ml/kg of feed. Samples supplemented with P1, P2, and P3 were designated P1, P2, and P3 diets, while feed added to freshwater was considered P4 (placebo). Gurami sago juvenile (initial weight 50±2.5 g and length 13.2±0.4 cm) were then placed in triplicate nets (2×1×1 m) in a freshwater concrete pond with a stocking density of 30 fish/net. Results The different products formulations had a significant effect (p<0.05) on growth performance. The weight gain in P1, P2, P3, and P4 diets were 167.24%, 193.99%, 134,22%, and 115.98%, respectively. For feed conversion efficiency, the values obtained were 0.65, 0.73, 0.65, and 0.64 in P1, P2, P3, and P4, respectively. Furthermore, supplementing commercial feed with varying products formulation had a significant impact (p<0.05) on the fatty acid composition and carcass body of gurami sago. Lipid content in fish carcass fed P1, P2, P3, and P4 were 2.90%, 4.42%, 2.98%, and 2.76%, respectively. Conclusion Based on the results, P2 contained a higher concentration of fatty acids compared to other diets, leading to increased body weight, feed efficiency, and carcass fatty acid composition in sago gurami reared in freshwater concrete ponds.

Characterization of Some Physico-Chemical Parameters of Water Bodies Inhabited by Small Indigenous Fish Species (SIFs): A Case Study

The physico-chemical properties of water bodies play crucial role in determining the life history as well as assemblage of inhabitant fish. The aim of this study was to analyse some water and sediment content parameters of inhabitant water bodies and investigate if there persists any correlation between physico-chemical parameters and fish assemblage. Freshwater ponds around Birbhum district, West Bengal (India) were selected for collection of water, sediment, and fish species samples. Temperature (°C), dissolved oxygen (DO), pH, nitrogen and phosphorous contents of water and sediment were analysed. Fish ecomorphological indices were calculated. The range of variations of the physico-chemical parameters in pond water were measured. For identifying the factors determining species assemblage, interaction effects of the factors throughout the seasons were first analysed. The analysis results of N and P contents from water and sediment showed no significant seasonal difference and correlation with assemblage. Next, fish species wise correlation of ecomorphological indices to temperature (T), dissolved oxygen (DO), total dissolved solid (TDS) and pH was analysed. Correlation analysis showed that temperature and pH had a moderate to strong correlation with most of the ecomorphological indices that determines the behaviour of SIFs as depicted by the indices. These two parameters could be considered as major direct parameters to understand the distribution of SIFs in water bodies.

Review of Central-Eastern European Propagation and Larvae Nursing Method for Common Carp (Cyprinus carpio L.).

Common carp (Cyprinus carpio L.) as a cultivated fish species has huge importance all over the world. According to FAO statistics, carp is the third most widely bred freshwater pond fish species; only two other Cyprinids (silver carp and grass carp) are bred in higher amounts. Carp is native all over Asia and in a large part of Europe. As a result of human intervention, at present, carp are widespread all over the world, except for the Arctic region. Carp breeding was launched in the antique period, in the ancient Chinese Empire and the Roman Empire. The presently applied method of breeding of common carp has a long evolution. From the effectiveness point of view, the propagation and early-life nursing are crucial parts of carp production, as they provide seed stocks for the further growing section. Without effective propagation, there is no intensive carp production. Nowadays, more advanced propagation methods are available all over the world; however, in the current review, only the main milestones and production efficiency of the propagation and nursing method used in the ponds of Eastern Central Europe are discussed. In the historical overview of carp reproduction, first the natural reproduction, then the semi-extensive and intensive hatchery propagation are presented and investigated in detail. The analysis focuses on the advantages and disadvantages of the method. In particular, the different important milestones of the advanced hatchery method are shown and explained. The effectiveness is proven even with practical calculations. Not only the reproduction, but the pond nursing method is also presented and discussed, concentrating on the management of evolutionarily adapted natural feeds (Zooplankton) and their effect on the survival of fish larvae.