Bottom Of Pond Research Articles

Impact of Sodium Carbonate on Seepage Reduction in Farm Irrigation Ponds

In this research, an economic layer using simple technology is evaluated to minimize seepage at the bottom of irrigation ponds. Since sodium carbonate diverges clay particles and decreases permeability by reducing porosity, it is recommended that sodium salts be used in mixed with soil at the bottom of irrigation ponds. The three types of soils were selected. First, the texture of the soils, second, chemical properties were determined for all three types of soils. Sodium carbonate were utilized in the percentages of 0, 2, 4, 6, 8, 10 and 12 by weight. Finally, the falling head test and the Scanning Electron Microscope (SEM) analysis were conducted. The results were illustrated as the tables and the graphs, and counter curves. The Results show that the soil 20% clay, the soil 15% clay and the soil 10% clay decrease seepage on average 42%, 64% and 71% respectively. The soil 10% clay has the greatest decrease of the three soil samples. Furthermore, in all three soil samples, the highest decrease in permeability was observed at 10% sodium carbonate. Overall, the results show that this pond sealer can be a suitable solution to reduce seepage in this type of pond.

Performance of Sediment Microbial Fuel Cells in Generating Electricity using Fish Wastewater and Shrimp Wastewater as a Nutrient and Their Effect on Waste Quality

Sediment Microbial Fuel Cell (MFC) is a technology that can convert chemical energy into electrical energy through the process of nutrient degradation by microbes. Sediment taken from the bottom of shrimp ponds was added as a source of microbes, while fish and shrimp wastewater were used as a source of nutrients for microbes. This study aims to measure the performance of the SMFC system on fish effluent and shrimp effluent to produce bio-electricity while reducing the waste load. The research method was experimental laboratories. The treatment given was the different types of electrodes, namely zinc-copper and aluminum-copper. In addition, 0.2 M KMnO4 electrolyte solution was used. This study consisted of four stages: the manufacture of nutrients from fish and shrimp wastewater, the manufacture of a dual chamber MFC bioreactor, the measurement of electrical values, and the analysis of waste quality. Experiments were carried out for 30 days by measuring electricity every 24 hours. The average value of electricity generated in the nutrients of fish wastewater with Zn/Cu electrodes was 0.705 V and Al/Cu was 0.472 V. Meanwhile, the average value of electricity in shrimp wastewater nutrients with Zn/Cu electrodes was 0.630 V and Al/Cu was 0.625 V. The number of colonies after adding sediment in the shrimp wastewater sample were 8.9 x 106 CFU/mL, the fish wastewater sample was 9.5 x 106 CFU/mL. It indicates the presence of microorganisms that play a role in the SMFC system

Compaction and strength behavior of Kaolin clay stabilized with Pond ash

In India 75% electricity is produced by thermal power plants using coal. Because the majority of the nation's coal reserves are of a lower non-cooking quality, more ash will be created as a result. One of the main causes of increased ash generation is the average 35% ash content of Indian coal. Fly ash makes up a relatively minor portion of the total amount of ash produced, with pond ash and bottom ash making up the rest. Therefore, there is a need to manage this material to avoid any environmental concerns. Another issue is the presence of problematic soil, in particular, expansive clays. Their presence at any site is a challenging task for geotechnical engineer. It is because they show high signs of volume change. To tackle this issue, engineers can go with either of the two available solutions: a) replacement and b) soil modification. Keeping this in view, the present investigation focuses on the utilization of Pond ash (PA) as an admixture in Kaolin clay (KC) as a soil modification method. Hence, in this paper, strength and compaction behaviour of KC stabilized with Pond ash PA was studied. For strength characteristics, unconfined compressive strength (UCS) and split tensile strength (STS) tests were carried out. Similarly, for compaction characteristics, modified proctor compaction tests were carried out. From the test results, it was observed that the inclusion of PA in KC significantly affected its compaction and strength characteristics. The optimum Pond ash content was observed to be 30% where, OMC, MDD, UCS and STS values were 17.30%, 1.60 g/cc, 360 kN/m2 and 88.70kN/m2, respectively.

Que tipo de lençol prefere o peixe dorminhoco gordo? Efeito da cor do fundo do tanque no crescimento e na saúde dos Dormitator latifrons (Richardson, 1844)

Abstract A little-studied characteristic of the Mexican native fish Dormitator latifrons is the effect that the color of the bottom or lining of ponds or tubs can have on their growth and blood parameters under controlled conditions. After a quarantine period in prophylactic treatment, an initial assay was performed. The organisms were grouped into four treatments (white, yellow, blue, and black) in triplicate, with 30 individuals with an average weight of 34.7± 2.5 g and average size of 12.5 ± 1.5 cm per tank. The trial lasted 60 days, after which a final biometry to all specimens and blood extractions to six random organisms per tank were performed. The following hematological and blood chemistry parameters were evaluated: erythrocytes, cell counts, and differential counts, as well as glucose, albumin, a/g ratio, and total proteins. Final weight, weight gain, and specific growth rate presented statistical differences between treatments (p<0.05), with dark bottoms (blue and black) above 80% of WG and above 1.0 of SGR. No statistically differences were found in hematological blood chemistry parameters (p>0.05). The growth results suggest that dark pond bottoms promote the adaptation of Dormitator latifrons by allowing it to avoid detection by predators through the adoption of a cryptic coloration. However, the species shows a great capacity for crypsis, being able to change its pigmentation to adapt to different bottom colors.

Effect of water quality ununiformity on production of marine medaka

The large amount of organic impurities deposited at the bottom of an intensive aquaculture pond often leads to the deterioration of the surrounding environment, creating additional environmental stresses on the farmed fish and affecting its growth. This study investigated the effect of water quality ununiformity on growth, feeding behavior, and stress tolerance of marine medaka (Oryzias melastigma) through differences of residence time in different water quality areas in the same aquaculture system. Through the pre-test, the flow field distribution in the aquarium for cultured experiment was clarified, and the water body in the aquarium was divided into the central area (Ce) and the corner area (Co) according to the water quality difference in different flow fields. Then, seven residence time gradients were set in Co, which were 24 h, 14.4 h, 7.2 h, 4.8 h, 2.4 h, and 0 h, respectively. That was, they accounted for 100% (P100), 60% (P60), 30% (P30), 20% (P20), 10% (P10), and 0% (P0) of a whole day, respectively. The results showed that, all water quality indicators such as dissolved oxygen (DO), pH, nitrite (NO2−-N) and non-ionic ammonia (NH3−N) in Ce and Co were consistent with the requirements of the standard (GB11607–89) during the 28-day cultured experiment, but the water quality in Co was gradually worse than that in Ce, with the prolonging cultured period. In spite of increasing the body length and body weight of medaka in all treatments, their growth rates had significant differences among several treatments (P0 = P10 = P20 > P30 > P60 = P100). And the fish's growth, feeding efficiency, and stress resistance decreased with the increase of residence time in Co (P < 0.05). Through nonlinear regression analysis, it was predicted that the accumulation of residence time of marine medaka stayed in the coner area was >6.667 h, its feeding behavior would be affected, and the corresponding appetite and food intake, immunity to disease and growth rate would all decreased. Attaining uniformity of water quality in aquaculture system may help improve fish welfare and increase the sustainability of aquaculture.

Supersaturated Solar Ponds for Enhanced Thermal Insulation by the Spontaneous Formation of a Thin Film Gas at the Bottom

Abstract In this work the novel approach of supersaturated solar ponds to enhance thermal insulation of the pond by the spontaneous formation of a thin film gas blanketing its bottom which is covered by active nucleation sites is discussed. Utilizing a simplified physical model an expression for the heat transfer and the increase of temperature at the bottom of the solar pond was derived.

Biological parameters, culture potential and nutritional quality of freshwater mussel Lamellidens marginalis (Lamarck, 1819)

Lamellidens marginalis (Lamarck, 1819), is a widely distributed mussel species in India and it is an important bivalve that can be used for the production of pearl. In the present study, L. marginalis were collected from low lying areas around Patna and analysed for length-weight relationship, proximate composition, amino acid concentration and fatty acid profiling. Growth study was also conducted for a period of 160 days to record the performance of this species, when reared at subsurface and bottom of a fish pond. The length-weight relationship was found to be Y=3.856X-12.81 and growth coefficient “b” was significantly higher indicating allometric growth pattern. Crude protein, fat, ash and moisture content in the flesh recorded were 7.19, 1.64, 3.70 and 83.92% respectively. Among essential amino acids, lysine was most abundant and low levels of isoleucine was recorded, while among non-essential amino acids, glutamate was dominant. Moreover, 32 fatty acids were recorded in the mussel including omega-3-fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Off-bottom culture in the pond performed better than on-bottom culture. Percentage body weight gain (BWG%) and specific growth rate (SGR%) were also higher for off-bottom grown mussels. Keywords: Amino acid, Growth, Lamellidens marginalis, Length-weight relationship, Protein, Survival

The application of an enhanced salinity-gradient solar pond with nucleation matrix in lithium extraction from Zabuye salt lake in Tibet

The utilization of salinity-gradient solar ponds (SGSPs) to extract lithium from salt lake brine is one of the most direct and effective uses of solar energy. The Qinghai-Tibet Plateau in China is rich in unique solar energy resources, as well as various types of salt lakes with abundant lithium resources. Among them, Zabuye salt lake in Tibet is a typical lithium-rich carbonate salt lake, and it has successfully realized the industrialization of lithium extraction from brine for the first time by using the SGSP. In recent years, with the continuous improvement of lithium resource market, the demand for lithium has further grown. There are some bottleneck problems restricting the lithium carbonate production in the lithium extraction technology with traditional SGSPs, which must be overcome, such as the slower heating rate, smaller heating amplitude, longer production cycle, lower crystallization efficiency and so on. From the angle of green environmental protection and high-efficiency technology, this research focused on the temperature field and salinity field distribution of the traditional SGSP and the special crystallization behavior of lithium carbonate, and carried out experimental research on process optimization in Zabuye mining area. Based on the heterogeneous nucleation theory, the use of an enhanced SGSP with a nucleation matrix for assisting the crystallization of lithium carbonate was proposed. The change of crystallization behavior of lithium carbonate, the influence of matrix materials and the spatial distribution on the crystallization effect were investigated. The results show that the enhanced SGSP with the nucleation matrix has a significant effect of increasing the production of lithium carbonate, and the lithium mixed salt attached to the nucleation matrix is of a higher grade and a lower moisture content. The yield per unit area of lithium carbonate on the nucleation matrix made of the gauze and plastic net is equivalent to that on the slope and bottom of the solar pond, and the grade of lithium carbonate approaches 80 %. The yield per unit area of lithium carbonate on the nucleation matrix made of tumbleweed is about four times as much as is achieved with other materials and the crystallization exceeds expectations. It is concluded that the application of the enhanced SGSP with the nucleation matrix can improve the crystallization efficiency, the output and the grade of lithium carbonate to a certain extent and this optimization technique will provide an important theoretical basis and application support for green, efficient development of lithium resources from salt lake brine.

Automatic measuring shrimp body length using CNN and an underwater imaging system

Farming of the Pacific white shrimp (Penaeus vannamei Boone, 1931) is among the largest aquaculture industries worldwide. Pond culture is an efficient and frequently used method in shrimp cultivation. Shrimp body length is a key indicator for feeding management. Conventionally, the shrimp body length is determined by observing the shrimp on feeding trays; however, this conventional approach is a time-consuming and labour-intensive process, and relies on the experience of shrimp farmers. This study proposes an automated approach for detecting shrimps and measuring their body lengths at the bottom of aquaculture ponds using the images captured from an underwater video system. The system included a camera equipped with an infrared LED illuminator. The shrimp in the images were classified into two categories, measurable and visible. A convolutional neural network model, YOLOv4-tiny, was trained to detect shrimps in the images. Subsequently, image processing algorithms were applied to segment the detected shrimps from their background and to estimate the shrimp body lengths. The trained YOLOv4-tiny model achieved an average precision of 93.24% in detecting the measurable shrimps. The proposed body length estimation approach achieved a mean absolute error and a mean absolute relative error of 3.5 mm and 5.09%, respectively. The proposed approach overcomes the challenge of directly measuring shrimp body length at the bottom of aquaculture ponds without disrupting their feeding process. The proposed approach can thus benefit aquaculture operations by providing information about the underwater behaviours of shrimps.

Improvement of Water Quality by Light-Emitting Diode Illumination at the Bottom of a Field Experimental Pond

Remediation of water quality by stimulating algal photosynthesis using light-emitting diodes (LEDs) has attracted attention, but few studies have examined this in outdoor freshwater environments. To understand the effects of LED illumination on water quality, the dissolved oxygen (DO), temperature, pH, and electric conductivity were monitored over 5 months in three depressions with or without a red/blue LED light at the bottom of an experimental pond. The effects of the blue LED on water quality were evident in the period with less rainfall after the change of water quality to an equilibrium state; DO and pH were higher, and EC was lower for the blue LED than for the control. The diel changes of these variables were also lower for the blue LED. The effects of the red LED on DO and pH were also evident, but to a lesser extent compared to those of the blue LED. A vertical mixing of water associated with a nighttime cooling of the surface water was suggested by a rapid DO increase after a temperature decrease in the control. Such internal water circulation and an inflow of water after rainfall might have obscured the LED effects in the rainy period. The bottom water of the blue LED had a higher density and species richness of phytoplankton than that of the control at the end of the experiment. A lower density of phytoplankton and higher nutrient concentrations in the red LED might have been due to a higher density and feeding activity by zooplankton. Our results confirmed the applicability of LED illumination in stimulating algal photosynthesis, and in improving the oxygen condition of the bottom water in freshwater ponds.

Numerical Simulation of Deformation and Failure of Drainage Boat Pond Caused by Underground Coal Mining-Induced Subsidence

The prediction of surface subsidence after underground coal mining is of practical significance for land planning and utilization in subsidence area. For a case study, the deformation and failure of a drainage boat pond caused by an underground coal mining-induced subsidence are investigated (the drainage boat pond is located in the Nanyang Lake Farm, Jining City, China). A mining subsidence prediction model suitable for the irregular coalface is established using the improved probability integral method to analyze the subsidence parameters. A numerical model of the boat pond deformation is established to simulate the stress, displacement, and plastic zone distribution of the boat pond. The boat pond deformation prevention structure is proposed from the prospects of pond bottom, pond slope, and pond slope protection. Moreover, the reinforcement of drainage boat pond is achieved in five steps. Finally, the deformation and failure state of the reinforcement boat pond under coal mining subsidence is simulated, and the rationality of the reinforcement measures is also verified by a field investigation. The research results have an important practical significance for water resource protection and structure construction in underground coal mining-induced subsidence.

PRODUCTION OF SHRIMP IN INTENSIVE AQUACULTURE SYSTEM OF VANAME SHRIMP (Litopenaeus vannamei) USING DIFFERENT CULTURAL SLUDGE MANAGEMENT METHODS

The main problem in intensive shrimp pond culture is a decrease in the quality of proper water during shrimp rearing and the emergence of disease. This problem resulted in decreased productivity of vaname shrimp. One of the efforts made is through the application of sludge management methods, with the aim of reducing the pile of sludge at the bottom of intensive ponds. Sludge management methods include the system, CRS (Close Resirculating System), Semi Close, and biofloc. The writing method used is literature study, for data analysis by comparing the average production data and water quality in each system. Sludge management in the CRS system, move the remaining organic material into the settling pond. In semi close system, remove sludge periodically through central draine. sludge management in the biofloc system, utilizing heterotopic bacteria to treat the remaining organic matter. The largest Average Daily Gain (ADG) is present in the bioflocked system at 0.16 g / day and the smallest in the semi close system at 0.11 g / day. Survival rate (SR) is the highest survival rate in the biofloc system with SR reaching 88%, and the lowest in the CRS system, namely 81%. The best Feed Convertion Ratio (FCR) in the biofloc system is that the FCR value reaches 1.26, the next is the CRS system with FCR 1.33, and in the semi-close system the FCR value reaches 1.93. The best sludge management system of the three systems is the biofloc system. The average daily water quality data of the three systems are still in optimal conditions, although the parameters of ammonia, nitrite, and nitrate are high, but at the survival rate of the shrimp the three systems are still above 80%.

THE DESIGN MODEL OF INTENSIVE VANAME SHRIMP PONDS FOR ECO-GREEN AQUACULTURE DEVELOPMENT IN THE AREA OF PROBOLINGGO, EAST JAVA, INDONESIA

Probolinggo, East Java, Indonesia, is an area with a high potential for shrimp aquaculture because these areas meet the criteria for candidate vaname shrimp aquaculture. Probolinggo in tropical regions with stable climate dan sea waves that have the potential for vaname shrimp aquaculture. The analysis required the following data: tidal data, topographic maps, network layouts, and water quality data for shrimp. This research was conducted by using the facilities at the brackish water and Marine Fisheries Laboratory of Probolinggo; an eco-green aquaculture circulation system was modeled and assessed using shrimp pond. First, the survey was located in Probolinggo City area, with coordinates 7° 44? 30.03? S and 113° 13? 58.68?. The methods used hydrological analysis: Water needs analysis for aquaculture irrigation based on the rules given by the Food and Agriculture Organization and water circulation analysis (Feedpedia, 2016). Material strength analysis of the embankments of the model pools: The comparison of area ratio toward embankment type dimension, design of dike and ponds, water filling discharge of brackish-water pond, and stages for ponds model design development. The results of the research suggested that dike should be planned to be as high as 1.5 m at the highest tide. The results of observations and tables of tidal recordings that had been verified then became the primary benchmark for planning the shrimp pond bottom. Based on the results of the analysis, it was found that the tidal height in the study location areas ranged from 2.5 to 3 m. A total of 80% of the area was used for production ponds.

Dammed water quality—Longitudinal stream responses below beaver ponds in the Umpqua River Basin, Oregon

AbstractBeaver‐related restoration (BRR) has gained popularity as a means of improving stream ecosystems, but the effects are not fully understood. Studies of dissolved oxygen (DO) and water temperature, key water quality metrics for salmonids, have demonstrated improved conditions in some cases, but warming and decreased DO have been more commonly reported in meta‐analyses. These results point to the contingencies that can influence outcomes from BRR. We examined water quality related to beaver ponds in a diverse coastal watershed (Umpqua River Basin, OR, USA). We monitored water temperature 0–400 m above and below beaver ponds and at pond surfaces and bottoms across seven study sites from June through September of 2019. DO was also recorded at two sites at pond surfaces and pond bottoms. Downstream monthly mean daily maximum temperatures were warmer than upstream reference locations by up to 1.9°C at beaver dam outlets but this heating signal attenuated with downstream distance. Downstream warming was greatest in June and July and best predicted by pond bottom temperatures. DO at pond surfaces and bottoms were hypoxic (≤5 mg/L) for more than half of the 32‐day monitoring period. Water temperatures increased for short distances below monitored beaver ponds and observed oxygen conditions within ponds were largely unsuitable for salmonid fishes. These findings contrast with some commonly stated expectations of BRR, and we recommend that managers consider these expectations prior to implementation. In some cases, project goals may override water quality concerns but in streams where temperature or DO restoration are objectives, managers may consider using BRR techniques with caution.

Minimum Requirement to Improve Quality before Discharging from Hybrid Red Tilapia Intensive Cage-Culture in Earthen Ponds to the Environment

This study determined a practical method to reduce environmental pollution by wastewater from fish ponds. Water quality in three hybrid red tilapia ponds (0.24 ha) was examined before and during harvest at five water depths of 10, 20, 50, 100, and 150 cm, as well as at the water surface and pond bottom. All water samples were analyzed for BOD, TN, TP, TAN, TS, TSS, and SS, with results compared with the Thailand control standard for freshwater aquaculture effluent. All quality parameters of the seven water samples showed statistical significance (p&lt;0.05) that increased with water depth. Degradation was highest in the bottom 50 cm of the fish pond. Limiting drainage to a depth of 50 cm was achieved by tilting the drainage pipe, and the resulting effluent met all water quality parameter standards. At a water depth of 50 cm, the remaining water was drained using a water pump, and all water quality parameters failed to meet the required standards. When this water was allowed to settle for 24 h, BOD, TN, TP, TAN, and TSS reduced to 21.06%, 2.42%, 11.68%, 5.47%, and 43.36% of full pond values, respectively. Results suggested sedimentation as a practical technique requiring a smaller pond area to reduce environmental pollution.

Enrichment of polystyrene microplastics induces histological damage, oxidative stress, Keap1-Nrf2 signaling pathway-related gene expression in loach juveniles (Paramisgurnus dabryanus)

Polystyrene microplastics (PS-MPs, particle size<5 mm) cause great harm to aquatic organisms. However, their precise effects are not completely understood. In China, placing plastic film at the pond bottom has become an important loach aquaculture mode. In this mode, MPs will affect loach health. This study investigated the enrichment of PS-MPs and its effects on the growth, liver histomorphology, antioxidant enzymes, and Keap1-Nrf2 signaling pathway-related gene expression in loach juveniles (Paramisgurnus dabryanus). The loach juveniles were raised at the concentration of 1000 μg/L fluorescent polystyrene microplastics (PS-MPs) with particle size of 0.5 µm or 5 µm for seven days, the results showed that fluorescent PS-MPs were found to be enriched in liver, intestine, and gill, and the enrichment amount was higher in liver than in gill and intestine (P < 0.05). Furthermore, the enrichment amount of different-sized PS-MPs was different in liver, gill, and intestine. The loach juveniles were cultured for 21 days in the water of the concentration of 100 or 1000 μg/L PS-MPs with particle size of 0.5 µm or 5 µm, the results showed that the survival rate, weight gain rate, and specific growth rate of loach juveniles were significantly reduced. The histological analysis revealed that PS-MPs caused liver damage. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), and acetylcholinesterase (AChE) were decreased with the extended exposure to PS-MPs. Generally, the expressions of Nrf2 and Keap1 showed the similar change trend. From 7–14 day, the expression trend of oxidative stressed-related genes was not completely consistent with that of Nrf2 gene, but on day 21, the gene expression trend of oxidative stress-related SOD, CAT, and GSH-PX in the downstream of Keap1-Nrf2 signaling pathway was roughly consistent with that of Nrf2 gene. Basically, the change trends of these three gene expression were similar to those of their corresponding enzyme activities. This study provides theoretical basis for the toxicological effects of PS-MPs on freshwater fish.

Identification of Viral Nervous Necrosis (VNN) in Grouper Fish (Epinephelus sp.) by Reverse Transcriptase-Polymerase Chain Reaction

Viral Nervous Necrosis (VNN) is a Nodaviridae virus-infected snapper and grouper fish, especially in the larval and seed stages targeted eye and nervous organ. Abnormal swimming was shown by fish behavior at the bottom pond. This study aimed to compare the identification of VNN through three different methods of RNA extraction from the organ target and amplification was carried out by Reverse Transcription of cDNA followed by Polymerase Chain Reaction (PCR) and quantitative real-time PCR (qPCR) technique. Herein, The RNA target from the organ from VNN-positive grouper fish samples targeted RNA2 region with 230-bp in electrophoresis gel and 69-bp by TAM-probe from qPCR were successfully converted and amplified from all RNA extraction kits. Different results of VNN amplified-cDNA were RNA extraction methods-dependent. Amplification using Tri Reagent® extraction kit showed the best result, with a large amount of RNA genome with good purity and showed clear results from PCR and qPCR. Furthermore, the sensitivity of RNA extraction methods was different from 50-100 ng total RNA/reaction. It was concluded that all RNA extraction kits can be used for the detection of the VNN genome by PCR and qPCR technique while resulting in different RNA yields. Overall, this study offers suitable methods to extract the VNN genome from grouper fish.&#x0D;

Physiological Ecology of Winter Hibernation by the High-Altitude Frog Nanorana parkeri.

AbstractThe Xizang plateau frog, Nanorana parkeri (Anura: Dicroglossidae), enters a dormant state in the winter in response to seasonal cold and lack of food. To investigate the physiological and ecological characteristics of overwintering in this species, we measured habitat conditions (hibernacula temperatures, body temperature, and water quality variables), morphology, metabolite concentrations, total antioxidant capacity (T-AOC), and bacteria-killing ability (BKA) of plasma during summer and winter. We found that N. parkeri hibernates underwater at the bottom of ponds (10-20-cm depth). Dissolved oxygen content in the water decreases significantly (by 12%) in the winter compared with summer, suggesting that overwintering N. parkeri may experience hypoxia. Body mass, body mass index, hepatosomatic index, and hepatic glycogen concentration all increased significantly in winter-collected frogs as compared to summer-collected individuals, indicating that overwintering N. parkeri accumulates high fuel/energy reserves to support prolonged periods of hibernation. A significant reduction in glucose, urea, and lactate concentrations in most organs may be closely related to metabolic depression in overwintering N. parkeri. Liver lactate concentration rose significantly in winter-collected frogs, suggesting that anaerobic metabolism dominates when this species overwinters. The T-AOC of plasma showed a significant reduction in winter, suggesting a reduced need for antioxidant defenses. Oppositely, the BKA of plasma increased significantly in winter versus summer, indicating that innate immunity was enhanced during overwintering. In summary, these behavioral (migrating to caves), physiological, and biochemical adjustments may be key for the successful overwintering of this high-altitude frog.

The age and quality of pond bottom soil affect water quality and production of Pangasius hypophthalmus in the tropical environment

Pangasius hypophthalmus is the most cultured freshwater fish by smallholder farmers in Indonesia. One of the main challenges in the production is the highly weathered and infertile soils on the bottom of a pond that influences aquaculture productivity. This work investigated the effects of pond age on soil quality, water quality, benthic algae population, and P. hypophthalmus production. We carried out a field experiment in a randomized design with pond age of 4 levels: Ponds aged 0–5 years (P1), 6–10 years (P2), 11–15 years (P3), and 16–20 years (P4). The soil is a Typic Palaeudult (Ultisol), and fish were grown for three months. The results showed that the chemical soil quality parameters and soil organic matter content increased linearly with pond age, resulting in the enhancement of water quality parameters. The increase in nitrate and phosphate directly affected benthic algae richness. These, in turn, in the highest fish production in P3, 6.4 kg/m2, specific growth rate was 3.76 %/d, survival rate of 66.7%, and feed conversion ratio of 1.8%. Linear correlation coefficients indicated that the contents of total N, total P, and organic carbon in the bottom soil of the pond were related to the increase in phosphate, nitrate, and organic matter content in pond water. Total N content, total P, carbon organic matter, C/N ratio, and CEC value in pond bottom soil significantly correlated to Pangus fish production. C/N ratio, CEC value in pond bottom soil, and CO2 concentration in pond water significantly correlated to fish survival rate. Multiple linear regression indicated that fish production was significantly related to the pond age, water NH3, total alkalinity, and soil total P and C/N ratio (R2 = 0.99, P < 0.001). Increased soil C/N ratio caused a negative effect on fish production. The results suggested that old-aged ponds, with proper management, act as a nutrient sink, resulting in increased aquaculture production. The implementation of the best practices will benefit the Pangus culture in the tropical environment.

COMPARATIVE STUDY OF ZOOPLANKTON IN MAKHANA CULTIVATION POND AND PERENNIAL FISH POND IN DARBHANGA, NORTH BIHAR

Darbhanga district of North Bihar, India lying between latitudes 26o 10¢ - 26o 17¢ N and longitudes 85o 54¢E - 85o 9¢, is traversed with fish and Makhana ponds. These water bodies can be profitably managed for cultivation of fish and Makhana (Euryale ferox), which are of high nutritive and medicinal value and fetch high price in National and International markets. Fishery in these ponds is a traditional practice without much intervention, excepting some stocking and harvesting. The present investigation was carried out on the zooplankton diversity, which is an important component of the food chain and fish yield to a great extent depends on their abundance. Makhana (Euryale ferox Salisb) plant, belonging to family Nymphaeaceae, is grown in ponds continuously for years. After harvesting of Makhana seeds from the bottom of ponds, the left over seeds serve as planting material for the next season. These Makhana growing ponds undergo gradual dereliction and get enriched with nutrients through anthropogenic and biotic sewers leading to eutrophication. Dehadrai (1994) opined that despite high organic nutrients in the pond soil due to the decay and decomposition of the Makhana plants, the plankton production remains sparse due to the shaded surface by the sprawling Makhana leaves during May to September. As a result, the metabolic gases remain in unfavorable proportions throughout the year making Makhana cultivated swamps completely unfavorable for cultivation of fish. Laal (1981) reported abiotic and biotic features of Makhana ponds and fish yield therein @ 200 kg ha-1yr-1. However, meager information is available on the relation between physico-chemical environment and dynamics of production respectively. Zooplankton production in the aquaculture in the paramonial fish pond has also been studied for comparison.