Experimental Ponds Research Articles

Sublethal Effects of Acoustic Dummy Tag Implantation and External Tags in Silver Carp

AbstractTelemetry data collected via internally implanted transmitters are commonly used to monitor and manage invasive Silver Carp Hypophthalmichthys molitrix. However, the extent to which posttagging effects may influence fish behavior is generally overlooked in telemetry studies. Moreover, internal telemetry tags are often combined with an external tag that can also affect fish growth and survival. This study used two pond experiments to (1) evaluate the temporal effects of internal telemetry tags, external jaw tags, and the combination of the two tags on survival, relative weight, growth, and inflammation; and (2) compare the effects of two external tag types (jaw and loop tags) on Silver Carp. Response variables were evaluated at three time points: 1, 2, and 5 months posttagging. Growth and relative weight were lower in fish that received jaw tags than in the control group or in fish that received internal tags only; however, growth was different at 1 month posttagging but not at 2 months posttagging, indicating potential compensatory growth. Shedding rate of internal tags was 14%; after 5 months, inflammation was absent and tags were encapsulated in tissue. Survival was similar between loop‐ and jaw‐tagged fish (73%), although growth was lower in jaw‐tagged fish. Results indicate that survival effects and sublethal effects of telemetry tagging may be temporary, and researchers should examine detection data from within 1–2 months of tagging for possible postsurgery effects. Jaw tags reduced growth, and loop tags had reduced retention; therefore, further evaluation of alternative external tags is needed to optimize telemetry studies focused on Silver Carp. Additionally, researchers need to carefully evaluate which external tag to use to facilitate the returns of more expensive acoustic telemetry tags and whether external tags are necessary in a particular case.

Biocontrol of Oreochromis mossambicus Population by Chitala chitala (Hamilton, 1822) in a Composite Carp Culture System of Purulia District in West Bengal, India

Aims: Pond-based carp production in the Purulia district in West Bengal, India is confronted with several challenges. This study aimed to establish an alternative semi-intensive carp production method for the district by addressing an endemic challenge i.e. recruitment of O. mossambicus, through an endangered (EN) and native predatory fish, Chitala chitala.
 Study Design: Present study has been conducted on two numbers of perennial water resources with 1 ha effective area; where annual production of Indian Major Carps (IMC) and impact of O. mossambicus and C. chitala on the same culture system have been compared.
 Place and Duration of Study: This study was conducted in farm conditions from 2018 to 2020, in two freshwater earthen ponds, Gosai Bundh (N23.47737/E86.79032) and Bara Notun Bundh (N23°46439/E86°65080), at Uluberia village under Kashipur Block of Purulia district in West Bengal, India.
 Methodology: Stocking density of Indian Major Carp (IMC) fingerlings was maintained at 8000 numbers (4:3:3 ratio of catla : rohu : mrigala) per ha (T1). After getting contaminated by O. mossambicus, wild C. chitala juveniles have been introduced in the similar facility (T2). Results of T1 and T2 were compared with control pond (C) containing IMC only. Recruitment of O. mossambicus and growth performance of C. chitala and IMCs determined periodically and annually.
 Results: Increasing growth of C. chitala showed contrasting impact over O. mossambicus fry recruitment. Survival percentage of C. chitala remains high in T2. While, poorest growth performance of IMCs have been observed in T1. Among IMC’s C. catla showed best survivality in every experimental ponds.
 Conclusion: Excessive recruitment of the O. mossambicus population can be controlled by C. chitala in a pond-based IMC culture system.

EFFECT OF RESTRICTED FEEDING ON GROWTH PERFORMANCE AND FEED UTILIZATION OF FRESHWATER PRAWN (Macrobrachium rosenbergii) IN POND AQUACULTURE SYSTEM

The present study aimed to evaluate the effect of rate restricted feeding on the growth performance and feed utilization efficiency of prawn (Macrobrachium rosenbergii) in improved traditional pond culture system. There was a control group (T2,) ad libitum of prawn) and two treatments which were 25% reduction(T2) and 50% reduction (T3) of artificial feed than control and each treatment were 25% reduction(T2) and 50% reduction (T3) of artificial feed than control and each treatment was triplicated. After nine experimental ponds (each was 120 m2) preparation, prawn PL was reared in the nursery pond for 45 days to become juvenile and the juvenile was then stocked in grow out at density of 2/m2. After 100 days of culture, the final mean weight was 16.14±8.2, 16.56±1.57 and 19.33±7.75 g for T1, T2 and T3 respectively. Higher SGR (2.89 % BW/d) was found in T3 which was significantly (p<0.05) higher than T1 (2.67 % BW/d) and T2 (2.72 %BW/d). Significantly (p<0.05) lowest survival rate (71%) was observed for T3 and highest survival rate (93%) was found forT1. The feed conversion efficiency (FCR) decreased significantly (p<0.05) with increasing feed restriction and lowest value (0.81) was observed for T3. The protein efficiency ratio (PER) and net apparent protein utilization (NPUa) found to increase with increasing feed restriction which indicates the better utilization of feed. The present study indicates that prawns are subjected to rate restriction of feeding condition was able to maintain the same and even high growth rate as control.

Effect of addition of carbon and probiotics on water quality, production performance, and health of catfish (Clarias gariepinus) in biofloc systems

This study aimed to evaluate the use of organic carbon and probiotics on water quality, production performance, and haematological status in sangkuriang catfish. This experiment used a completely randomized design with four treatments: addition of organic carbon (C), the addition of probiotics (P), the addition of organic carbon and probiotics (CP), and control (K), each treatment with three replications. Catfish seeds measuring 1.86±0.60g 500 tails were stocked in a 1m3 pond. The seeds were fed commercial feed with a dose of 5% of the biomass. The results showed that the four treatments pH, dissolved oxygen, nitrite, and the bacterial population, had no significant effect. In contrast, TSS, TAN, and floc volume had a significant effect but were still in a good range of growth catfish. Specific growth rate, absolute growth, and final weight were higher in adding organic carbon (C) and (CP), survival, and the best feed conversion ratio in addition to organic carbon and probiotics than in control. Low haemoglobin and erythrocyte values were indicated as the cause of fish death. Based on the study's results, it can be concluded that adding organic carbon to the experimental pond can increase the specific growth rate. Adding organic carbon and probiotics increased survival and final weight but decreased the best feed conversion ratio compared to controls. Therefore, from the study results, it is enough for fish cultivators to utilize the addition of organic carbon to provide the best growth for fish cultured in a biofloc system.

Optimization of Arthrospira platensis Growth by Adding Different Carbon Sources on the Culture Media of Catfish Cultivation Waste and Technical Fertilizer

Nutrients (C, N, and P) can affect the growth and biochemical content of Arthrospira platensis . Ethanol can be a potential carbon source compared to glucose and acetic acid. Glycerol is also potential as a carbon source for the growth of Arthrospira platensis . This research was carried out from June to July 2021 at the Aquaculture Laboratory and Experimental Pond Laboratory of the Aquaculture Study Program, Sriwijaya University. The research method used Completely Randomized Design (CRD) factorial with 2 factors consisting of the first factor with 3 treatments and the second factor with 2 treatments and 3 replications. The inoculant was cultured in liquid fertilizer technical F/2 media for culture stock as initial inoculum with a density of ± 1.0 g L-ˡ. Parameters observed were the density, the specific growth rate, and water quality. The results showed that M1S3 treatment had the highest density with a value reaching 4.95 g L -1 and the highest specific growth rate of 0,33% per day. ANOVA test result showed that the addition of carbon sources in the culture media of fertilizer and technical waste had a significant effect (P<0.05) on the growth rate of Arthrospira platensis . The water quality parameters of each treatment were suitable for Arthrospira platensis culture.

Metagenomics Reveal Microbial Effects of Lotus Root-Fish Co-Culture on Nitrogen Cycling in Aquaculture Pond Sediments.

Feed input leads to a large amount of nitrogen-containing sediment accumulating in the substrate in the pond culture process, threatening the safety of aquaculture production. Planting lotus roots (Nelumbo nucifera Gaertn.) in ponds can accelerate the removal of bottom nitrogen, while the role of nitrogen cycle-related microorganisms in the removal is still unclear. In this study, eight yellow catfish (Pelteobagrus fulvidraco) culture ponds with the same basic situation were divided into fishponds with planted lotus roots and ponds with only fish farming. Sediment samples were taken from the fishponds with planted lotus roots and the ponds with only fish farming before and after fish farming, marked as FPB, FPA, FOB, and FOA, respectively, and subjected to physicochemical and metagenomic sequencing analyses. The results show that the contents of NH4+, NO2−, TN, TP, and OM were significantly lower (p < 0.05) in FPA than in FOA. The abundance of metabolic pathways for inorganic nitrogen transformation and ammonia assimilation increased considerably after culture compared to the sediments before culture. A total of eight ammonia production pathways and two ammonia utilization pathways were annotated in the sediments of the experimental ponds, with a very high abundance of ammonia assimilation. Acinetobacter and Pseudomonas (34.67%, 18.02%) were the dominant bacteria in the pond sediments before culture, which changed to Thiobacillus (12.16%) after culture. The FPA had significantly higher relative abundances of Thiobacillus denitrificans and Sulfuricella denitrificans, and the FOA had significantly a higher abundance of Microcystis aeruginosa compared to other samples. The massive growth of Microcystis aeruginosa provided two new inorganic nitrogen metabolic pathways and one organic nitrogen metabolic pathway for FOA. The relative abundances of these three microorganisms were negatively correlated with NH4+ content (p < 0.01) and significantly positively correlated with AP, OM content, and pH value. Compared with ponds with only fish farming, lotus root–fish co-culture can significantly reduce the nitrogen content in sediment, increase the abundance of denitrifying bacteria, and inhibit algae growth. Still, it has little effect on the abundance of nitrogen cycle-related enzymes and genes. In summary, it is shown that, although lotus roots promote the growth of denitrifying microorganisms in the sediment, nitrogen removal relies mainly on nutrient uptake by lotus roots.

Investigation of internal organs and additive tissue of hybrid hypophthalmichthys (Hypophthalmichthys spp.) as a promising raw material for the production of dietary nutritional products

Preservation of the nutritional value of fish and the useful qualities of its rich composition is extremely important. The urgent task of the food industry is to develop and create quality food products that meet modern production trends and compete in domestic and foreign markets. This scientific paper describes studies aimed at assessing the specific weight (%) of essential nutrients (glycogen, proteins, and lipids) in particular organs and tissues of different size and mass groups of the hybrid of silver and bighead carp experimental ponds and reservoirs of Ukraine. To achieve the goal in the research process, fish farming, biochemical (study of total protein, lipids, and carbohydrates), and statistical (mathematical processing of research results) research methods were used. In all size and mass groups of the hybrid of silver and bighead carp from ponds and reservoirs in 2017, 2018, and 2019, mostly satisfactory values of general metabolism indicators were found - glycogen, proteins, and lipids in the liver, gills, and muscles of fish. In annual fish of winter ponds, total protein and glycogen content in all organs and tissues was slightly reduced. The organisms of biennial fish from feeding ponds were characterized by fluctuations in the content of glycogen in the liver (it was the highest in fish, 3.28 – 3.33%). Significant fluctuations in the total protein content of muscle, liver, and gills and a slight excess of glycogen in the liver and lipids in the gills of three-year-olds were observed in the reservoirs. The difference found in the availability of essential nutrients in the body of the studied fish indicates a change in the intensity and direction of their metabolic processes. However, their physiological condition at the time of the study was within normal limits.

Periphyton: A natural fish food item for replacement of feed at optimized substrate surface area for cost-effective production in brackishwater polyculture

Periphyton community grown on submerged substrate in water could serve as a preferred natural food item to herbivorous and omnivorous fish and crustacean species. To determine the optimum substrate area for the growth of periphyton biomass serving as natural food and to reduce the requirement of pellet feed quantity, a 150-day pond experiment was conducted with four treatments of brackishwater polyculture: total feeding and no periphyton substrate (P0), and partial feeding with periphyton grown on nylon net substrate equivalent to 50 (P50), 75 (P75) and 100 (P100) % of pond surface area. Each treatment had three randomly assigned replicate ponds (50 m2). After 15 days of substrate fixation in the surface layer of ponds up to 50 cm water depth, stocking was made with seeds of Mugil cephalus Linnaeus, 1758, Planiliza parsia (Hamilton, 1822), Chanos chanos (Forsskål, 1775) and Penaeus monodon Fabricius, 1798 at 1800, 18000, 2000 and 30,000 number ha−1, respectively. A low-cost pellet feed (30.76% crude protein) was provided at 6–3% of fish biomass per day. Dry matter (DM) of periphyton biomass was estimated from each replicate pond under P50, P75 and P100 from 15 × 15 cm2 net substrate, and then total periphyton DM was calculated according to the substrate surface area at 15-day intervals. Then, the total periphyton biomass was divided to find out daily DM availability. The feed amount in P50, P75 and P100 ponds was reduced proportionately to the equivalent daily periphyton DM availability and the feeding at this reduced quantity was continued for 15 days. The experiment revealed significantly lower levels of nitrogenous and phosphorus compounds, and dissolved organic carbon content in water of P75 and P100, compared to that of P0 and P50 (P < 0.05) and there were interaction effects of experimental period and periphyton substrate area on these parameters. All the species had an increasing growth pattern with experimental period and there was an interaction effect of experimental period and periphyton substrate area on growth of these species, indicating periphyton had positive effects. The highest specific growth rate was recorded in P. monodon and the lowest was in M. cephalus. Pooled survival of fishes and shrimp, and total productivity did not differ among treatments (P > 0.05). Although, the highest level of feed reduction (42%) by the utilization of periphyton biomass was in P100, P75 performed better in terms of productivity and economic return with 30% feed reduction in polyculture. Similarly, there was 26–41% reduction in feed conversion ratio with the highest level being in P100 (41%), followed by P75 (40%) in comparison to P0. Moreover, carcass composition of cultured fishes and shrimp indicated that periphyton based systems with partial feeding could meet up the nutrient requirement of the animals with no negative effects in comparison to the feed-based system. Therefore, this study suggests that provision of periphyton substrate equivalent to 75% of pond surface area along with partial feeding is the most appropriate approach for achieving higher return with environmental sustainability in brackishwater polyculture.

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.

Effects of High Ammonium Loading on Two Submersed Macrophytes of Different Growth Form Based on an 18-Month Pond Experiment.

Ammonium (NH4-N) produces a paradoxical effect on submersed macrophytes because it is not only the preferred nitrogen source for the growth of plants but also threatens the growth of plants at high concentration. Whether short-term and small-scale physiological toxicity experiments at an individual level can reflect the effects of high ammonium on populations of submersed macrophytes in natural conditions is still unclear. In this study, an 18-month experiment was conducted in six 600 m2 ponds subjected to different levels of ammonium loading. The effects of high ammonium on populations of canopy-forming Myriophyllum spicatum and rosette-forming Vallisneria natans were explored. The results showed that M. spicatum and V. natans populations can develop high cover and height at high ammonium concentration (7 mg/L) at short-term exposures, and V. natans may be tolerant to 18 mg/L ammonium concentration. However, the cover of M. spicatum and the height of both species were inhibited at 2.4 mg/L at long-term exposures. The height of M. spicatum was two to six times higher than that of V. natans across all treatments and control by the end of the experiment, and the cover of M. spicatum was 7–11 times higher than that of V. natans in most NH4-N loading treatments, except the cover of M. spicatum in the highest NH4-N loading treatment with 18 mg/L NH4-N. The rosette-forming V. natans resists ammonium stress by slow growth (shoot elongation) to reduce consumption, while canopy-forming species resist ammonium stress by shoot elongation and canopy development to capture light. Although increasing ammonium concentration may induce severe stress on M. spicatum, the morphological characteristics of this species may, to some extent, release the plants from this stress. Our present study indicates that the negative effects of ammonium stress on the development of populations increased with exposure duration, and the submersed macrophyte community with stronger ability for light capture and dispersal may resist high ammonium stress. Nevertheless, in strongly ammonium-enriched systems, competition and succession cannot be neglected.

Novel trophic subsidies from recreational angling transform the trophic ecology of freshwater fishes

Abstract Angling is a globally popular leisure activity. There are over 31 million anglers in Europe, many of which target species of the Cyprinidae family in lowland freshwater ecosystems using methods generally involving bait (e.g. groundbaits, seeds and pellets), with large bait inputs possible in periods of high angling activity. While these bait inputs act as novel trophic subsidies (‘angling subsidy’), substantial knowledge gaps remain on their influence on freshwater food webs, including on fish trophic niche size and position. The effects of angling subsidies on the trophic ecology of cyprinid fish populations and their macroinvertebrate prey resources were investigated in field studies comparing waters of high angling activity (‘subsidised fisheries’) versus low angling activity (‘non‐subsidised fisheries’), and complemented by a pond experiment using two cyprinid species in subsidy absence/presence. Methods were based on stable isotope analysis, with angling subsidies being δ13C enriched and, generally, δ15N depleted compared to macroinvertebrate prey resources. In the subsidised fisheries, while there were minimal influences of the baits on macroinvertebrate stable isotope values, the effects of the subsidies on all fish species were to substantially δ13C enrich and δ15N deplete their isotopic niches. However, patterns of interspecific niche divergence remained similar between the species in subsidy presence. In the pond experiment, there was strong isotopic association between the two fish species and macroinvertebrate putative prey in subsidy absence. In treatments that then exposed both species to angling subsidies, their stable isotope values shifted to enriched δ13C. Synthesis and application. Where angling activity is high, angling baits can provide strong trophic subsidies to freshwater fish, but with minimal effects on other trophic levels. Their regular input into freshwaters can provide some substantial benefits for fish (e.g. increased growth rates) and fisheries (e.g. elevated carrying capacity, higher catch rates), but can also increase nutrient enrichment and potentially raise concerns on angling ethics. Thus, in allowing the use of these baits, especially in relatively high quantities, managers must balance the benefits they can deliver to fish and fisheries versus the adverse effects their use can have on freshwater organisms and ecosystem functioning.

Особенности раскрытия ростовой и адаптогенной потенции у двух- и трехлеток растительноядных рыб в условиях Калининградской области

This article reviews the experiment of growing two-year old three-year old carp, grass carp, silver and bighead carp in experimental ponds of EEF KSTU from May to October 2021 in order to determine their growth and adaptagenic potency. According to the results of the evaluation of growth potential disclosure of herbivorous fish, we observed similar dynamics of the rate of mass accumulation at two and three years of age. Maximum values were observed in summer (July-August) and minimum values in autumn (September-October). Close resolution of growth potency was observed for three-year-old silver and bighead carp. According to the results of the assessment of the disclosure of adaptogenic potency, the highest value of the ecological coefficient was observed for bigheaded carp (70% of the influence on growth from ecological factors). In other groups of two-year-olds, the disclosure of this factor was at an average level (39-56 %), and in three-year-olds it was at a low level (33 %). The survival rate of the study groups did not exceed 80-92%. According to the results of the study, the disclosure of growth and adaptogenic potency for two-year old three-year-old fish in ponds of EEF in 2021 was disclosed at the average level of values, the growing season corresponded to IV fish farming zone.

Effect of Different Natural Substrates on Periphyton Production under Earthen Lined Seawater Pond for Periphyton based Aquaculture

Background: Periphyton-based aquaculture improves water quality, provides a natural food supplement, limits harmful bacteria, provides a safe haven for shrimp to escape, and adds living space. The impacts of diverse natural substrates on periphyton formation were examined under earthen lined pond seawater systems as a first step in analysing the sustainability of periphyton-based shrimp production. Methods: Natural substrates such as coconut coir, coconut shell and split bamboo pole were placed inside the earthen lined pond filled with seawater for duration of 45 days. Periphyton samples were obtained from each type of substrate on the 15th, 30th and 45th days of the experiment. For all substrates, periphyton biomass and chlorophyll ‘a’ pigment in the periphyton were measured at depths of 0 to 40 cm, 40 to 80 cm and 80 to 120 cm. Physico-chemical parameters of experiment pond water were recorded during periphyton samplings. Result: During the experiment, coconut coir showed higher periphyton biomass in terms of dry matter (DM) (3.4995 0.31201 mg/cm2) and chlorophyll ‘a’ pigment (3.2949 0. 27076 mg/cm2). Duncan’s Multiple Range Test and One Way ANOVA of diverse data reveal a significant difference (P 0.05) between the substrates in periphyton biomass and chlorophyll ‘a’ pigment. In all three substrates, a Student’s ‘t’ test analysis shows that the upper 0 to 40 cm depth yields more periphyton biomass and chlorophyll ‘a’ content than the other levels. Coconut coir was the best natural substrate for periphyton growth among the three.

Agonistic behaviour of wild eels and depressed survival and growth of farmed eels in mixed rearing experiments.

To contribute to improving eel stocking procedures, the survival, growth and behaviour of farmed Japanese eels reared together with wild individuals were evaluated to learn about possible encounters of farmed- and stocked eels with wild eels. Two experiments were conducted to evaluate the (a) effect of the presence of wild eels on survival and growth of farmed eels in experimental ponds and (b) behavioural differences between wild and farmed eels placed in a small tank. In the survival and growth experiment, significantly lower survival and growth rates of farmed eels reared with wild eels were observed compared with farmed eels reared without wild eels (control). In the behavioural observations, the authors observed significantly higher occupation rates of a refuge and more frequent biting for wild eels, indicating a dominance of wild eels over farmed eels. Because wild and farmed eels used in the current experiments belong to the same genetic population, these differences resulted within one generation through the aquaculture rearing process.

Effect of steel-wires and paraffin composite phase change materials on the heat exchange and exergetic performance of salt gradient solar pond

The addition of Phase Change Materials (PCM) to the salt gradient solar pond can significantly increase the heat capacity of the solar pond. Paraffin wax has a suitable range of phase transitions temperature and is feasible to be applied in solar pond. However, the poor thermal conductivity of paraffin is detrimental to thermal storage and release. In this study, the heat transfer behavior for the composite PCM of paraffin and steel wires has been studied firstly, the results shows that adding steel wires in paraffin improve the heat transfer performance obviously. With 10wt% adding percent, the maximum of heat transfer coefficient is 18.17 W/m2 °C−1 with increment of 18.84 % in melting process; and the maximum is 21.59 W/m2 °C−1 with increment of 20.88% during freezing process. Secondly, experiment study has been conducted in an experimental solar pond, with 20 PCM capsule tubes added, adding RT 50 and RT 60 made the day–night temperature differences 2.87 °C and 2.53 °C smaller than that of without any PCM conditions. In this study, adding RT 50 and RT 60 in solar pond achieve 9.34% and 14.13% exergy increments respectively. The study suggested that adding PCM to solar pond improves the quality of the heat energy of solar pond, and further extends the heat application scope of solar pond.

Nutrient mass balance for improved traditional coastal shrimp ponds of Bangladesh

Three category of tidal water exchange system depended ponds have been selected for the experiments which were canal connected, river connected and pond connected pond. Present study was undertaken to estimate the nutrient balance into the coastal shrimp ponds of Cox’s Bazar coastal region. It was found that mineral fertilizer, organic fertilizer, feed, fish and shrimp fry, water supply and rainfall are the nutrient input and crop product (fish, shrimp, crab), crop residues, denitrification, water discharge and sedimentation are the nutrient output for shrimp pond. Estimation of overall nutrient mass balance per hector basis indicates that fertilizer was the highest nutrient contributor as followed by the supplementary feed into the experimental ponds. The total inputs of nitrogen and phosphorus were 78.87 kgha-1cycle-1 and 42.85 kgha-1cycle-1 respectively. Among the input only 34.6 % of nitrogen and 7.20 % of phosphorus were removed as harvested shrimp, fish and crab. A large portion, 38.58 % of N and 91.38 % of P were remained in the sediments and unaccounted for. From the investigation on nutrient balance for 3 categories of shrimp ponds it was concluded that Reuse water or pond connected pond system for coastal shrimp ponds should not be practiced anywhere in Bangladesh&#x0D; &#x0D;

Choline Chloride Induces Growth Performance of Indian Major Carps and Air-Breathing Fish Species with an Outcome of Quality Food-Fish under a Semi-Intensive Culture System: A Biochemical Investigation.

The present study was intended to determine the possible influences of direct field application of choline chloride into pond water in addition to farm-made-aqua-feed under a semi-intensive culture system on the growth and biochemical parameters of two Indian major carps (IMCs), Catla catla (Catla) and Labeo rohita (Rahu), and two air-breathing species, Clarias batrachus (Magur) and Anabas testudineus (Koi), cultured in a ratio of 2:5:1:1 (Catla/Rahu/Magur/Koi) in three experimental ponds for a period of 90 days during the breeding season (June to August). Results were compared with control (C: fed only with farm-made-aqua-feed) and treatment (T: P1 and P2: farm-made-aqua-feed plus choline chloride into pond water directly at the rate of 350 g bigha–1 fortnightly or 350 g per 1600 square meter fortnightly). A significant increasing trend was observed in the growth parameters including total length-final (TLF), standard length-final (SLF), mean weight-final (MWF), % gain of mean total length (MTL), % gain of mean standard length (MSL), % weight gain (WG), specific growth rate (SGR) % per day, and survivability %. However, a reverse pattern was noticed in the food conversion ratio (FCR) both in IMCs and air-breathing fish species under choline supplementation. Serum biochemical responses, e.g., total protein (PRO), lactate dehydrogenase (LDH), glucose (GLU), and calcium (Ca) showed significant enhancement, and alkaline phosphatase (ALP), alanine amino transaminase (ALT), aspartate amino transaminase (AST), cholesterol (CHOLES), and triglycerides (Trig) showed gradual significant reduction during the breeding season under choline exposure. Treated fishes showed prevention from liver dysfunction and fatty liver formation, and increased body crude protein content. Results indicated favorable growth and yield, which may benefit fish farmers during their culture practices, and the output fish species under choline supplementation resulted in quality food-fish for human consumption.

Assessing growth performance and survival of wild shad Tenualosa ilisha fry in two earthen ponds with different feeding regime: A new insight for conservation

The present study describes the rearing and growth performance of Hilsa (Tenualosa ilisha) fry in experimental trial performed in earthen pond ecosystem located adjacent to river Rupnarayan for developing in-situ rearing protocol of fry collected from the wild sources. The seed was collected during May, 2020 from the river and stocked in two different rearing ponds. One of the ponds was provided with artificial feed and another fed with chicken offal to raise the production of zooplankton. Routine monitoring of water and soil quality parameters as well as other biotic communities like plankton was performed to understand the dynamics of ecological conditions in relation to changes in length and weight. The results of PCA between sediment quality and specific growth of fish indicated the strong positive loading of available nitrogen, available phosphate and free calcium carbonate, while moderate positive loading was observed with percentage of silt. Interestingly, it is observed that survivability rate of fish was approximately 80% in both the ponds. The results indicated natural growth fish was considerably well in both the experimental ponds. However, higher growth of juveniles were observed in the pond 2 with higher phytoplankton density (9120cells/L) than pond 1 having lower phytoplankton density (920cells/L) at the end of the experiments. The water quality parameters were comparable in both the experimental ponds. Based on this study it is evident that plankton (especially zooplankton) has induced better growth in pond 2 and possible incorporation of live feed along with formulated feed might trigger better growth of the stocked Hilsa. The present study provides new insight in developing field based approaches for successful rearing and conservation of threatened Hilsa in Indian waters.

The Effect of Probiotics on Bacillus sp Population, Water Quality, and Growth Rate of Striped Catfish (Pangasianodon hypophthalmus) in Pounds without Water Change

This study aims to determine the effect of adding probiotics to water quality, Bacillus sp population, and production performance of catfish. Completely randomized design experiment with three treatments ponds without probiotics without changing water (NN), ponds plus probiotics without changing water (PNW), and ponds given probiotics with 10% water change per day (PW). three replications each. The results showed that the water quality in the experimental pond was still within the acceptable range for fish growth. The TOM levels of the ponds that were given probiotics were lower than the control ponds. The PNW ponds with the lowest TOM levels turned out to have the highest TAN levels. The population of Bacillus sp in NN, PNW, and PW ponds was not significantly different (P&gt;0.05), however, the population of Bacillus PNW was 42.51% higher than NN, while PW was 17.38% higher than NN ponds. The abundance of plankton and the uniformity index of NN, PNW, and PW ponds were not significantly different (P&gt;0.05). The abundance of plankton in NN was 203% higher than PNW and PW was 73% higher than PNW ponds. The growth rate and individual weight gain were significantly different (P&lt;0.05), the growth rate of the PNW pond was higher than that of the NN pond, while the PW pond was the same as the PNW and NN ponds. The highest additional individual weight was in the PW pond, followed by the PNW pond and the lowest in the NN pond. Survival and biomass addition were not significantly different (P&gt;0.05).

Performance of experimental bioretention cells during the first year of operation

Abstract Detailed data on the long-term performance of bioretention cells (BC) for stormwater management are sparse. This research aimed at setting up and testing an infrastructure that will provide the data on hydrologic and chemical performance of BC. Two identical experimental BC’s were built. The monitoring methodology monitoring was developed and tested during a first growing season with the first BC supplied with natural rainfall, while the second BC was used for ponding experiments. Key layer of the BCs, a biofilter, was composed of sand, compost and topsoil. Both BCs are equipped with sensors monitoring the components of water balance and the water potential of the biofilter. High levels of total suspended solids were detected in the outflow. The runoff coefficient for the entire period of the growing season was 0.72 in the first BC and 0.86 in the second BC, while the peak outflow reduction for individual rainfall episodes ranged between 75% to 95% for the first BC and 19% to 30% for the second BC. Saturated hydraulic conductivity of the biofilter in the first BC decreased by two orders of magnitudes after the first year of operation. Retention curves of the biofilter changed due to material consolidation.