Pond Size Research Articles

Assessing the impacts of zeolite on water quality, growth performance, heavy metal content and health condition of farmed tilapia (Oreochromis niloticus)

The rapid expansion and intensification of tilapia (Oreochromis niloticus) aquaculture in Bangladesh results in an increasing tendency of administering more pharmaceuticals in fish health management. Hence, with the aim of investigating the effects of zeolite (a water and sediment treatment compound) on water quality, growth performance, hematology, gut microbial content, and heavy metal content of Oreochromis niloticus, an experiment was performed for 126 days in six experimental earthen ponds (each pond size is one decimal). The stocking density was 300 fry/decimal. Zeolite was applied directly into the water in treatment ponds at a rate of 200 g/decimal during pond preparation and 100 g/decimal/15 days intervals during the culture period as recommended by the manufacturing company. The results indicated that zeolite had a significant effect (p < 0.05) on all growth indices assessed in all three experimental stages (0–42 days, 43–84 days, 85–126 days) in treatment ponds compared to control ones, except condition factor (CF) at the first stage. Hematological results implied that the application of zeolite in treatment pond water had no significant effect on the red blood cell (RBC) and white blood cell (WBC) of experimental fish blood compared to the control. However, a significant effect on the blood glucose level and total viable count (TVC) of the experimental fish gut was observed due to the addition of zeolite in the treatment ponds. Zeolite supplementation in treatment pond water significantly reduced the concentrations of different heavy metals in pond sediment, water and fish flesh compared to the control. Therefore, zeolite could be recommended for administration in aquaculture. Further research is required to find out whether a higher or lower dose of zeolite improves the water quality, growth performance and health condition, and decreases the heavy metal content of fish or not.

Surrogate-Based Multiobjective Optimization of Detention Pond Volume in Sponge City

Detention ponds are effective structures for stormwater management in the urban drainage system of sponge cities. The pond size is taken as the decision variable, while the cost, total suspended solids (TSS), and catchment peak outflow (CPO) serve as the objectives for optimizing the detention pond volume. First, we randomly generated 10,000 pond areas and input them into the stormwater management model to simulate the time series of outflow and suspended solids concentration, thereby generating samples by combining the set of pond area, corresponding cost, TSS, and CPO. Then, two backpropagation neural network models (i.e., BPNN-TSS and BPNN-CPO) were trained, tested, and evaluated for predicting TSS and CPO, respectively. We employed them as surrogates and used the non-dominated sorting genetic algorithm-II to solve the optimization problem. The results showed: (1) The BPNN models accurately predicted TSS and CPO (determination coefficient 0.988~0.996, Nash–Sutcliffe efficiency 0.988~0.997), and efficiently substituted stormwater management model simulations for optimization purposes (residuals −18.49~28.10 kg and −0.45~0.29 m3/s). (2) For the Pareto solutions, the detention pond reduced TSS by 0~8.33% and CPO by 0~72.44% and delayed their peaks by 4~52 min; the reduction in TSS and CPO tends to grow as pond size increases, and CPO reduction exhibits a minor marginal effect. (3) The surrogate-based approach saves 90.03% runtime while preserving the quality of the Pareto solutions, verifying reliability.

Small ponds have stronger potential for net nitrogen removal: Insight from direct dissolved N2 measurement

Growing demands for watershed nitrogen (N) removal have called attention to abundant small bodies of water such as ponds, which have long been heralded as efficient storage and processing systems. Although pond conservation, restoration, and creation have been widely implemented to mitigate N pollution, information is limited regarding the impact of size—that is, whether N removal potential and efficiency are dependent upon pond size. We investigated the dynamics of N removal rates in 56 ponds from a hilly watershed by studying their bimonthly N2 concentrations and fluxes. Our results showed that smaller ponds performed better in net N removal. This can be discerned from the areal N2 fluxes, which were the highest in small ponds (< 4, 000 m2). The corresponding N2 fluxes (4.73 ± 4.53 mmol N2 m−2 d−1) were 2 to 14 times greater than those observed in larger ponds. The N removal efficiency, a metric used to describe the portions of the substrates released as N2, was also significantly higher in the small ponds (∼8.7 %) than in the larger ponds (∼5.0 %). Further regression analysis showed that both areal N2 flux and N removal efficiency were negatively correlated with pond area. The underlying mechanisms behind the size effects of N removal could be attributed to small ponds having larger sediment contact area to water volume ratios. Thus, smaller ponds allow more opportunities for N to interact with bioactive sediments than larger ponds. Overall, our findings contribute to the understanding of the distal role of pond size in affecting N removal. This research also provides a strong rationale for considering the effects of system size when implementing management practices dedicated to maximizing N removal.

Channel Gradient as a Factor in the Distribution of Beaver Dams and Ponds on Small Rivers: A Case Study in the Northern Extremity of the Volga Upland, the East European Plain

A very noticeable increase in the beaver population (mainly the Eurasian beaver (Castor fiber L.)) in the East European Plain since the end of the 20th century through reintroduction contributed to the emergence of a large number of beaver dams and ponds, which resulted in the transformation of the channels and the hydrological regime of small rivers. In this paper, for the first time in the Middle Volga region, regularities in the distribution of beaver dams and ponds on small rivers were revealed based on a topographic survey of the river channel, regulated by beaver activity in recent decades. The materials of the paper were obtained during field (geodetic) work in August and September of 2022 in the valleys of two small rivers typical for the north of the Volga Upland, Morkváshinka River (16.6 km) and Morkváshka River (7.8 km), with subsequent statistical processing. According to the results obtained, all the dams we encountered were located in the sections of their channels with relatively small (up to 1%) and medium (1–3%) average gradients. In the upper reaches of the rivers, the expansion of beaver activity is limited to the large gradients of their channels. Along the entire length, there is an alternation of sectors with a “natural” (not regulated by beavers) channel and a cascade of beaver ponds. Drained (at the time of the survey) sectors without dams, as well as those with preserved and destroyed dams, were also identified on the Morkváshinka River. On the whole, 26–48% of the length of the studied rivers has been transformed by beaver activity. The average number of dams per kilometer of the watercourse is 3.7–5.1. The most favorable channel gradients for beaver activity are 3.6–16.6 m/km, or 0.36–1.66%. The average gradient of the channel, above which no beaver dams and related ponds were found in these rivers, is 30 m/km, or 3%. An increase in the channel gradient upstream of the rivers is reflected in the size of beaver dams and ponds. The beaver dams and ponds are slightly larger in the sections of the rivers with a relatively small average gradient than in the sections with a medium average gradient of the channel.

Integrated farming of stinging catfish (Heteropneustes fossilis) and rabbit (Oryctolagus cuniculus) in farmer’s pond

A study was carried out to evaluate the growth and production performances of stinging catfish (Heteropneustes fossilis) and rabbit (Oryctolagus cuniculus) under two treatments such as T1 (shing-rabbit integrated system) and T2 (shing monoculture) in farmers’ pond. Twelve ponds from two villages such as Sutiakhali and Salakandi under Mymensingh sadar upazila were selected for the study. The average pond size was 5.5±0.23decimal with a stocking density of 600 shing dec-1. The ponds were only fertilized with rabbit dung except at the time of pond preparationat a rate of 1 kg dec-1. Various environmental parameters such as temperature (oC), transparency (cm), PH, dissolve oxygen (mg L-1), PO4-P (mg L-1), NO3-N (mg L-1), NO2-N (mg L-1), NH3-N (mg L-1), chlorophyll and alkalinity (mg L-1) were monitored once in a week. The parameters were found to vary little from pond to pond and most of the parameters were within the suitable range for freshwater aquaculture in Bangladesh. The highest survival rate of fish was 95.36 ± 0.15 % in treatment T1 and the lowest was 90.39 ± 0.10 % in treatment T2. The survival rates of fish were not significantly different among the treatments (P &gt; 0.05). The production of fish in T1 and T2 treatment was 25.36 and 20.43 kg dec-1, respectively. Daily growth of shing in two treatments were 1.95 ± 0.01 and 1.88 ± 0.01 % respectively. The study revealed that integrated shing-rabbit would be highly profitable using improve extensive culture system in the rural household ponds through effectively reducing the use of pond fertilizer and fish feeding cost.&#x0D;

RELATIONSHIP BETWEEN PROFILE OF THE INLAND FISH FARMERS AND THEIR PLANNING ABILITY

The study was carried out in Anand district of Gujarat state with 150 randomly selected inland fish farmers. A pre-tested interview schedule was prepared in light of the objectives and respondents were interviewed either at their home or work place. Ex-post facto research design was used. For measurement of variables included in study, different scales and scoring techniques were used. The result designated that amongst the fifteen selected variables of the of inland fish farmers in the study annual income, participation in training, exposure to agricultural mass media, risk orientation, achievement motivation, scientific orientation, innovation proneness and self confidence had establish positive and significant relationship with the planning ability of inland fish farmers, whereas age, education, social participation, caste, contact with extension agency, pond size and economic motivation failed to show any significant influence on the managerial efficiency of inland fish farmers.

ECONOMIC ANALYSIS OF CATFISH FARMING AND ITS CONTRIBUTIONS TO HOUSEHOLD POVERTY ALLEVIATION IN ANAMBRA STATE, SOUTH EAST NIGERIA

The study analyzed factors influencing the potency of catfish farming determined the cost and returns of catfish farming, estimated the poverty status among catfish farmers and ascertained the contribution of catfish farming to household poverty alleviation in the study area. Primary data used for the study was collected using well-structured questionnaire which was administered to sampled Catfish farmers in the study area. In analyzing the data, descriptive statistical tools (frequency counts, means and percentages), enterprise budgeting techniques, Tobit regression model, expenditure approach of determining poverty line, Foster, Greer and Thorbecke technique and z-test were used. The results indicated that factors such as pond size (0.0004), feed (0.6411), labour (-0.0003), and farming experience (0.0105) had influence on potency of catfish farming . Net returns analysis result reveals a return on investment of ?1.51 and it implies that the catfish production enterprise generated 1.51 times more income than expenses incurred for the production, a gross ratio of 66% and a Profitability Index (PI) of 0.34 which means that for every naira earned as revenue, 0.34kobo was returned to the farmer as net income. This result surely indicates that cat fish production is highly lucrative in the study area. At 0.05 probability level, the calculated z value was statistically significant and thereby ascertained the positive contribution of catfish farming to household poverty alleviation. Based on this study, the following recommendations are made: Since catfish production are profitable, government need to devote more resources to the catfish farmers to ensure that the best practices are adopted for further sustainability of the agribusiness, farmers should be trained on how to compound different types of fish feed to enable them reduce cost of feed. In addition Government should ensure increased credit facilities by the financial institutions to enable the farmers spread out their scale of operation

Adoption of Scientific Practices in Fish Farming in Telangana State, India

The study was undertaken in six districts of Telangana state viz. Karimnagar, Kamareddy, Medak, Wanaparthy, Mahabubabad and Yadadri Bhuvanagiri during 2019-2022 with an aim to study the extent of adoption of scientific fish farming practices. Ten fish farmers were selected from each of the selected districts using simple random sampling technique thus constituting 60 fish farmers. A structured questionnaire was used to collect responses about the adoption of scientific fish farming specifically based on preliminary survey as well as focus group discussions. The results depicted that nearly half (48.33%) had medium level of adoption followed by high (38.33%) and low (13.34%) level of adoption respectively. The variables such as fish farming experience, annual income, Pond size, Economic motivation and innovativeness reflected the strong association and effect on the extent of adoption.

Relationships between summertime surface albedo and melt pond fraction in the central Arctic Ocean: The aggregate scale of albedo obtained on the MOSAiC floe

As part of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC), the HELiX uncrewed aircraft system (UAS) was deployed over the sea ice in the central Arctic Ocean during summer 2020. Albedo measurements were obtained with stabilized pyranometers, and melt pond fraction was calculated from orthomosaic imagery from a surface-imaging multispectral camera. This study analyzed HELiX flight data to provide insights on the temporal and spatial evolution of albedo and melt pond fraction of the MOSAiC floe during the melt season as it drifted south through Fram Strait. The surface albedo distributions showed peak values changing from high albedo (0.55–0.6) to lower values (0.3) as the season advanced. Inspired by methods developed for satellite data, an algorithm was established to retrieve melt pond fraction from the orthomosaic images. We demonstrate that the near-surface observations of melt pond fraction were highly dependent on sample area, offering insight into the influence of subgrid scale features and spatial heterogeneity in satellite observations. Vertical observations conducted with the HELiX were used to quantify the influence of melt pond scales on observed surface albedo as a function of sensor footprint. These scaling results were used to link surface-based measurements collected during MOSAiC to broader-scale satellite data to investigate the influence of surface features on observed albedo. Albedo values blend underlying features within the sensor footprint, as determined by the melt pond size and concentration. This study framed the downscaling (upscaling) problem related to the airborne (surface) observations of surface albedo across a variety of spatial scales.

Chance and necessity in the assembly of plant communities: Stochasticity increases with size, isolation and diversity of temporary ponds

Abstract Biodiversity emerges from niche mechanisms, in which the combination of traits determines species performance, and populations drift because of the inherent stochasticity of community assembly processes. Population biology dictates that small and isolated communities are more prone to show stochastic assemblages. However, a reduced mass effect in isolated communities may promote trait selection. In addition, large and connected communities have a larger species pool, higher functional redundancy, lower population sizes and more random recruitment, which also fosters stochasticity in community assembly. These contradictory expectations demand empirical analyses. Plant metacommunities in temporary ponds are assembled by the action of strong environmental filters and cover wide ranges of local community sizes and connectivity, representing ideal systems for identifying determinants of trait‐selection processes. Using a deviance partition method introduced by the theory of community assembly by trait selection, we evaluated the role of plant traits in local community assemblies along 60 communities from a 14‐year plant survey of temporary ponds. Variation in pond size, hydroperiod, connectitivity and heterogeneity determined a selection gradien in traits related to drought resistance, life history and disperal strategies; and also in the strength of trait‐mediated community assembly. The taxonomic and functional diversity of a pond and its physical heterogeneity fostered stochasticity in the assembly of the community, which also presented a hump‐shaped association with connectivity. The pond area increased taxonomic richness but decreased functional diversity, determining negative and positive indirect effects on stochasticity. Synthesis. Diversity provides the raw material for trait selection putatively reducing stochasticity, but here diversity was positively related to stochasticity. Having enough functional diversity, larger redundancy and lower population sizes in diverse communities is probably fostering stochastic assemblages. The hump‐shaped association between stochasticity and connectivity supports a larger role of trait selection in isolated systems due to a weak mass effect, but also on connected communities in which a set of more optimal traits for the selection scenario could be available. In the ongoing state of ecosystem fragmentation, these empirical trends contribute to the mechanistic understanding of the connection between landscape structure and biodiversity assembly.

Analysis of portable solar concrete ponds by using coal cinder to trap thermal energy of sustainable building using artificial intelligence

Cinder is a waste product made from the coal residue left over from power plant blast furnaces. Solar energy is a promising renewable energy source, but because of its erratic availability, energy storage technologies must be used. Our research suggests employing coal cinder (CC) to boost the thermal energy stored in transportable solar concrete ponds, combining rock mechanics with renewable energy. The concepts of renewable energy and rock mechanics are combined in this invention. Additionally, because it doesn't release any pollutants into the sky, it is great for low heat applications like building cooling and heating. However, due to its sporadic nature, solar energy requires effective energy storage to be used at night and in cloudy weather. By adding coal cinders to the bottom layer of a solar concrete pond in order to increase its heat energy, this work integrates rock mechanics with sustainable energy. A variety of small-scale research use the standard micro solar concrete ponds. Also offered is a numerical calculation for predicting energy development over a sizable area of a solar pond with a salt gradient. The coal cinders may significantly raise the temperature at the pond's bottom. With a constant temperature differential of 30 °C and 20 °C throughout the gradient layer for two different pond sizes with depths of 1.5 m and 1.0 m, this study provides thermal analysis of a salt gradient solar pond using machine learning as Particle Swarm Optimization (PSO) and extracting heat from the Lower Convective Zone (LCZ). Going through the regression indices (RMSE, R2, r), the energy efficiency (heat) of the first 1.5-meter-deep concrete pond varies between 22.1 and 11.3% throughout the winter. The energy performance of a solar pond decreases dramatically when the non-convective zone thickness and its size are decreased. For the two concrete ponds with depths of 1.5 m and 1.0 m, respectively, the annual average efficiencies are 23% and 16%. Hence, the solar pond demonstrates that it is an effective method for utilizing solar energy and may be a useful option for low-temperature energy needs, such as room heating.

Gender and Poverty Issues among Catfish Farmers in Ibadan Metropolis of Oyo State, Nigeria

This study aimed at finding the analysis of gender and poverty status among catfish farming households in the Ibadan Metropolis of Oyo State. The study was carried out in all eleven local government areas in the State. Six wards were randomly selected from each of the local government Areas from which two farming households were randomly selected based on probability proportionate to the population of farming households in each ward. Primary data were collected from farming households. The data generated were subjected to descriptive analysis on household socioeconomic characteristics and production system, Foster, Greek and Thorbecke weighted poverty indices alongside the Probit regression model. From the survey data, the value of the poverty line computed was N51150.57. Thus the farming household that earns less than the value of the poverty line were considered poor which is about 66.4% of the sampled households, while those that earn greater than equal to the value of the poverty line were considered to be non-poor which is 33.6% of the sampled households. This implies that the majority of the respondents live below the average income in the study area. Probit regression model result indicates the marital status of the household, farming experience, access to remittances, and the pond size (if large) are the four factors that affect the farmers significantly at 5%, 10%, 1% and 10% respectively. Premised on the findings, it was recommended among others that the gender gap between the male and female gender in terms of production should be bridged and there is an urgent need to encourage human capacity development among respondents since the study revealed that education of both males and females reduces poverty.

Hydrological Investigations in Red Soils of a Micro Catchment Area for Dugout Farm Pond at UAS Raichur Campus

Aims: To measure and characterize storm wise runoff for the catchment area of the farm pond and to correlate rainfall intensity and runoff relationship for the catchment area will help to design the appropriate size of the farm pond and waste weirs of the bunding system.&#x0D; Place and Duration of Study: The study was conducted in a micro catchment (field sized area) of a dugout farm pond, having an area of 6 ha located in the new area of UAS campus Raichur, which comes under Zone II in Region-I of Karnataka state. Geographically it is located at 16° 12′ N latitude and 77° 20′ E longitude and at an elevation of 389 m above the mean sea level (MSL). The study was conducted for a period of one year during 2019.&#x0D; Methodology: The existing farm pond constructed was used for conducting hydrological studies. The detailed soil and rainfall characterization of the study area has been made through appropriate methods. The rainfall intensity for each storm has been measured using self-recording rain gauge. The runoff has been measured at the out let of the field sized micro catchment area of farm pond using hydraulic structures coupled with automatic runoff recorder. The event wise rainfall, rainfall intensity and runoff have been measured and analysed to see the relationship between rainfall intensity and runoff with prevailing soil and topographical characteristics of the study area.&#x0D; Results: The percent runoff varied from 6.79 to 50.42 and highest was 50.42 per cent occurred on 25-10-2019 followed by 44.03, 39.36 and 37.46 per cent. The data shows that the individual storm wise percent runoff was quite high as compared to annual percent runoff of 15.99 per cent. The storm wise high runoff percent was due to the fact that high intensity of rainfall followed by high AMC in the soil. Further the minimum runoff yield of 142.66 m3 was observed on 18-07-2019 against the rainfall of 35.00 mm and maximum of 2985.48 m3 was yielded on 25-09-2109 against rainfall of 113.00 mm and followed by 1086.64 m3, 944.24 m3, 665.61 m3 and 431.25 m3 against rainfall of 46.00 mm, 42.00 mm, 22.00 mm and 48.00 mm respectively. The total annual runoff yield was found to be 6255.90 m3 against the rainfall of 651.50 mm. Therefore, there is a scope for harvesting excess quantity of runoff which is going as a waste. The existing pond capacity of 547.77 m3 is insufficient to store prevailing runoff generated in the catchment area and hence, pond capacity may be enhanced. The maximum intensity of rainfall and runoff during six events were showed statistically insignificant relationship with R2 value of 0.370. There is no correlation between intensity of rainfall and runoff.

Improving detention ponds for effective stormwater management and water quality enhancement under future climate change: a simulation study using the PCSWMM model

Urban surfaces are often covered by impermeable materials such as concrete and asphalt which intensify urban runoff and pollutant concentration during storm events, and lead to the deterioration of the quality of surrounding water bodies. Detention ponds are used in urban stormwater management, providing two-fold benefits: flood risk reduction and pollution load minimization. This paper investigates the performance of nine proposed detention ponds (across the city of Renton, Washington, USA) under different climate change scenarios. First, a statistical model was developed to estimate the pollutant load for the current and future periods and to understand the effects of increased rainfall on stormwater runoff and pollutant loads. The Personal Computer Storm Water Management Model (PCSWMM) platform is employed to calibrate an urban drainage model for quantifying stormwater runoff and corresponding pollutant loads. The calibrated model was used to investigate the performance of the proposed nine (9) detention ponds under future climate scenarios of 100-year design storms, leading to identifying if they are likely to reduce stormwater discharge and pollutant loads. Results indicated significant increases in stormwater pollutants due to increases in rainfall from 2023 to 2050 compared to the historical period 2000–2014. We found that the performance of the proposed detention ponds in reducing stormwater pollutants varied depending on the size and location of the detention ponds. Simulations for the future indicated that the selected detention ponds are likely to reduce the concentrations (loads) of different water quality constituents such as ammonia (NH3), nitrogen dioxide (NO2), nitrate (NO3), total phosphate (TP), and suspended solids (SS) ranging from 18 to 86%, 35–70%, 36–65%, 26–91%, and 34–81%, respectively. The study concluded that detention ponds can be used as a reliable solution for reducing stormwater flows and pollutant loads under a warmer future climate and an effective adaptation option to combat climate change related challenges in urban stormwater management.

The impact of mangroves in small-holder shrimp ponds in south-west Bangladesh on productivity and economic and environmental resilience

Aquaculture production in extensive shrimp ponds along mangrove coasts may be influenced by many factors such as pond size, pond management, species diversity of mangroves and aquaculture species used, as well as the position and abundance of mangroves in the ponds. A growing number of studies indicate the potential positive effects of mangrove presence on pond productivity. In this study we aimed to assess the influence of mangrove presence on pond production characteristics as observed in the south-western coastal region of Bangladesh where mangroves grow largely naturally in aquaculture ponds. Using structured interviews we quantified a large number of pond production parameters from mangrove-associated shrimp aquaculture in ponds with a wide range of mangrove coverage (0% - >50%) including total costs, revenues and net profits. The 435 ponds for which data were collected were distributed among 61 villages in four regional clusters. The regions differed significantly in terms of the species present, the total coverage of mangroves, and their position in and around the ponds. Mangrove presence in the ponds correlated strongly with pond productivity and farm profits. Mangrove presence was significantly associated with smaller ponds which had higher input costs and revenue per unit pond area than larger ponds but lower net profitability. Notwithstanding our large sample size, and contrary to our expectations, this study was not able to identify clear profit benefits of the association of mangroves with shrimp ponds. Among various possible explanations, we suggest that, as currently observed in Bangladesh, the presence of mangroves in aquaculture ponds yields little or at most sub-optimal financial benefits. Hence, our results seem to indicate that there is great scope for improving of mangrove-use in shrimp aquaculture. In that, one can expect the largest potential benefit of associating mangroves with shrimp culture in large ponds (“scale benefit”) in which mangroves are presently not being used. The great potential for mangroves to help boost pond productivity and bolster farm economic and environmental resilience clearly remains largely untapped. Our results suggest that further work is needed to help farmers better select appropriate mangrove species, the most suitable locations for planting mangroves and the best percentage of mangrove pond coverage to boost shrimp production. As our cross-sectional study only provides a baseline of mangrove association with shrimp ponds additional, properly controlled experiments following the “Before-after-control-impact (BACI)” design are also needed in order to be able to discern the true causal effects of mangroves on aquaculture production.

Spatial and Temporal Study of Supernatant Process Water Pond in Tailings Storage Facilities: Use of Remote Sensing Techniques for Preventing Mine Tailings Dam Failures

Considering the global impact on society due to tailings storage facilities (TSFs) accidents, this article describes a study to monitor mine tailings management and prevent mining tailings dam failures, considering the analysis of different TSFs real cases. The spatial and temporal dynamic behavior of the supernatant process water pond of the TSFs is studied as a critical issue, using remote sensing techniques based on multispectral satellite imagery. To understand the current state of the art, a brief description of engineering studies for the control and management of the supernatant process water pond in TSFs is presented. This research considers the main method of the study of practical cases with the use of techniques of multispectral interpretation of satellite images from the Sentinel 2 remote sensor. In addition, the management of tools such as Geographical Information System (GIS) and Google Earth Engine (GEE) is implemented, as well as the application of some spectral indices such as NDWI and the joint use of (i) NDVI, (ii) mNDWI, and (iii) EVI. Real TSF cases are analyzed, including the dam failures of Jagersfontain TSF in South Africa and Williamson TSF in Tanzania. Finally, this article concludes that the size, location, and temporal variability of the supernatant process water pond within a TSF has a direct impact on safety and the possible potential risk of the physical instability of tailings dams.

Design of Automatic Fish Feeding in Arduino-Based Catfish Farming

This Arduino-based fish feed aims to design and build a catfish feeder automatically based on the Arduino Uno-based fish feeding schedule. This feeder uses the RTC DS3231 to set the time and schedule for feeding fish which is equipped with a Servo Motor as a feed valve opener and an LCD as a clock and date display on the feed schedule. The weight of the feed issued is based on the weight of the catfish and the number of fish. The number of catfish in this study is 100 fish with a pond size of 2 meters by 2 meters. The scheduled feeding schedule is morning, afternoon, evening and night, depending on the age of the catfish. Considering that catfish are cannibals that eat their own kind and are nocturnal, that is, animals that are active at night and sleep during the day, it is best if some of the feed is given more in the afternoon or at night because the catfish's appetite is high at night. The feeding schedule is in the morning at 08.00, noon at 12.00, in the afternoon at 16.00 and at night at 20.00. The button on the remote will control how many times the feed will come out of the feed tray. When the feed in a fish feed container has run out, the ultrasonic sensor will work and an alarm will sound from the buzzer which sounds as a reminder. From the test results, it was obtained that the feed weight was regular after designing an Arduino Uno-based automatic fish feed structure, and the servo moved according to a predetermined schedule.

Factors Affecting Colony Size and Breeding Parameters of Eared Grebe (Podiceps nigricollis) in Carp Ponds

Understanding important factors for breeding Eared Grebes (Podiceps nigricollis) is essential for its conservation. We aimed to study the impact of some factors on nests and breeding success in this species in fishponds (S Poland). Number of Eared Grebe nests were counted on particular carp ponds. Pond size, vegetation cover, number of nests in colonies of associated gull or tern species, and age of stocked common carp (Cyprinus carpio) were determined for all ponds with nests. We also investigated the relationship between nest size, material used to construct them and clutch size. Number of Eared Grebe nests positively correlated with number of breeding pairs of associated colonial species (terns or gulls). Selection of the breeding site by the Eared Grebe can be explained by appropriate nest protection by large colonies of associated species (Whiskered Tern Chlidonias hybrida and Black-headed Gull Chroicocephalus ridibundus). Nest size was not related to clutch size. A negative relationship between breeding success and number of nests of Eared Grebe was found. Food is a not limiting factor for the Eared Grebe on fishponds with extensive production, and presumably other factors such as weather conditions may explain the low breeding success of this species.

Aquaculture Status in Southern Bangladesh With Special Emphasis on Disease Induced Loss

Culture fisheries contributes a major share of fisheries production of Bangladesh which is the accumulation of aquaculture production of every fish farms of the country. However, the actual production of cultured fish (finfish and shellfish) and cost-benefit of the farms are not well documented. Moreover, the farms must overcome a lot of constrains for sustainable production. The present study was thus designed to determine the present aquaculture status in some parts of Bangladesh and to identify the problems for the loss of aquaculture production through questionnaire survey between July 2019 and January 2020. The study areas included Bhola, Rangamati, Khulna, Satkhira, Jashore and Madaripur upazila. In the study area, the relationship between different aspects of aquaculture was determined where pond size and production cost per hectare; pond size and profit per hectare and per unit production cost and profit were found to be significantly and positively correlated. The production and production cost per hectare were also determined which were 3.52±0.40 metric tons and 6260±987 USD, respectively. The fish farmers reported some degrees of reduction of profits compare to the profit obtained during 2018-2019. The reduction of expected profit in different regions ranged between 10 and 33%. The major causes of the production loss in the survey regions were related to disease, seed and feed. Among different diseases viral, bacterial and parasitic diseases were reported where diseases were identified based on the symptoms. Findings of the present study suggest that incorporation of management, modern technology and economic aspects for steady growth of aquaculture sector is needed in Bangladesh. Dhaka Univ. J. Biol. Sci. 31(2): 257-271, 2022 (July)

Pengaruh Efisiensi Teknis Terhadap Pemilihan Lokasi Penjualan pada Usaha Tambak Bandeng di Indonesia

&lt;p&gt;&lt;em&gt;Milkfish farmers in Indonesia have several alternatives in selling their production,but the reality is most of them still sell their production on farm gate level. This is presumably due to the inefficient use of inputs and it has an impact on declining yields. Consequently, there’s a need for input improvement through the technical efficiency in order to increase the amount of yields, so the farmers have a stronger bargaining position and have the opportunity to access markets that offer a higher price. Therefore, the objectives of this study are (1) to measure the technical efficiency, (2) to analyze the correlation between technical efficiency and sales site choice, and (3) to analyze other factors that affect the farmers’ sale site choice. This study used data from census of agriculture 2013 as many as 1015 milkfish farmers in West Java. DEA approach is used to measure the technical efficiency, while logistic regression is used to analyze the factors that influence the farmers’ decisions. The results showed that the milkfish farmers have an average technical efficiency of 0.66. This technical efficiency had a positive influence on the selection of sale sites to the outside, such as cooperatives, exports, and processing industries. The significant factors were age, institutional membership, education level, pond size, price, and quantity of production.&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt; &lt;/em&gt;&lt;/p&gt;