Pond Conditions Research Articles

Predicting Tilapia Productivity in Geothermal Ponds: A Genetic Algorithm Approach for Sustainable Aquaculture Practices

This study presents a case focused on sustainable farming practices, specifically the cultivation of tilapia (Mozambican and aureus species) in ponds with geothermal water. This research aims to optimize the hydrochemical regime of experimental ponds to enhance the growth metrics and external characteristics of tilapia breeders. The dataset encompasses the hydrochemical parameters and the fish feeding base from experimental geothermal ponds where tilapia were cultivated. Genetic algorithms (GA) were employed for hyperparameter optimization (HPO) of deep neural networks (DNN) to enhance the prediction of fish productivity in each pond under varying conditions, achieving an R2 score of 0.94. This GA-driven HPO process is a robust method for optimizing aquaculture practices by accurately predicting how different pond conditions and feed bases influence the productivity of tilapia. By accurately determining these factors, the model promotes sustainable practices, improving breeding outcomes and maximizing productivity in tilapia aquaculture. This approach can also be applied to other aquaculture systems, enhancing efficiency and sustainability across various species.

АРАЛ ҚАЯЗЫНЫҢ (LUCIOBARBUS BRACHYCEPHALUS) ШАБАҚТАРЫН ҚОЛДАН ӨСІРУ ТӘЖІРИБЕСІ

This article presents the results of research to assess the growth of fingerlings of the rare and endangered Aral barbel (Luciobarbus brachycephalus) in fish farms in the Kyzylorda region. The research cover in detail the work on the cultivation of larvae in pond conditions obtained from individuals of barbel caught in the Syrdarya River in the territory of the Kyzylorda region. For research purposes, the characteristics of the pond and the water source in it are given, as well as a description of the tools for conducting control catches. The results of control catches of barbel larvae from the moment they were planted in the pond were analyzed to determine the growth rates of their main biological indicators. The deadlines and intervals of control work are also described in detail. In the conditions of the pond, the obtained results of analyses of indicators of the Fulton fatness index of barbel fry in comparison with representatives of barbel in their natural habitat are presented. During the results of growing barbel fingerlings, it was shown that the average weight of fry in the 2nd decade of September reached 15.1 g, and this indicator gives full opportunity to harvest fish planting material in the conditions of fish farms in the region.

Exploring environmental condition of silvofishery pond to support the sustainability of mangrove management in Berau Regency, Indonesia

The integration of mangrove management with aquaculture, termed the silvofishery pond system, has been implemented in Berau Regency, East Kalimantan Province, Indonesia. A detailed survey was conducted to assess the features of mangrove terrain surrounding silvofishery ponds, aiming to enhance the productive and sustainable management of these mangrove areas in Berau Regency. This survey focused on various land characteristics such as topography, tidal patterns, water quality, soil properties, climate, and the state of mangrove vegetation. The health of mangrove vegetation was assessed by calculating the Important Value Index (IVI) across different growth stages: trees, saplings, and seedlings. The findings reveal that the mangrove adjacent to the silvofishery ponds in Berau Regency are home to 14 species from 13 genera and 10 families. Rhizophora mucronata displayed the highest IVI scores across all growth stages: 75.17% for trees, 93.14% for saplings, and 66.98% for seedlings, the latter shared with Rhizophora apiculata. Soil quality emerged as a critical limiting factor for land use in silvofishery ponds, particularly due to high potential acidity (low pH) and low nitrogen (N) content. To enhance soil quality, it is recommended that soil management practices such as remediation (via drying, submerging, flushing, or liming) and N supplementation through fertilization be employed. Furthermore, given the sparse mangrove vegetation density at the tree level (1,012 trees/ha), efforts to promote natural mangrove regeneration and prevent deforestation and degradation are advised. Considering the unique characteristics of the mangroves, the implementation of the komplangan model—a silvofishery approach that segregates mangroves restoration pond from grow-out ponds—is recommended to boost productivity and ensure sustainability in the coastal region of Berau.

Impact of climatic factors on water quality parameters in tilapia broodfish ponds and predictive modeling of pond water temperature with ARIMAX

Climate change represents a considerable threat to aquatic ecosystems, potentially affecting various water quality parameters.The study aims to assess the impacts climatic factors on the water quality parameters in tilapia broodfish pond and forecasting of water temperature in a tilapia broodfish pond using the ARIMAX model. Daily longitudinal time series data on water quality parameters were collected from the pond, while monthly climatic data were obtained from the Bangladesh Meteorological Department. Water temperature exhibited seasonal variation, peaking at 31.23 °C in October and dropping to 20.8 °C in December. pH levels ranged from 7.36 to 10.32, with the lowest recorded in December and the highest in August. Dissolved oxygen levels varied from 7.09 mg/L to 10.65 mg/L, with the lowest in September and the highest in January. Ammonia levels were highest in February at 0.33 mg/L. Water transparency ranged from 15.37 to 28 inches, with the highest in January and the lowest in June. Climatic factors significantly influenced these variations, as specified by Canonical correlation analysis (CCA). The best-fitting model, ARIMAX (1, 0, 1), indicated a fluctuating trend influenced by important exogenous factors like air temperature and solar intensity. By the end January 2025, the water temperature is expected to rise to 27.93 °C. This is a noticeable increase started from November to January. These higher temperatures may improve tilapia broodfish growth and development earlier. But the temperatures are predicted to drop started from February to March, which could negatively affect tilapia growth and development. A clear seasonal fluctuating pattern is exhibited in the future. These findings provide important insights for researchers, policymakers, academics, and those involved in tilapia farming. By considering air temperature and solar intensity in planning, stakeholders can better anticipate future pond conditions. Developing adaptive management strategies to reduce negative impacts and make the most of favorable conditions will be essential for sustainable tilapia production in the context of climate change.

The mangrove oyster Saccostrea palmula is an option for artisanal aquaculture development in the Mexican Central Pacific

The mangrove oyster Saccostrea palmula is a relatively small but emerging species in aquaculture, and it is necessary to resume and increase studies on its cultivation. Therefore, we carried out a study that includes three main components for developing S. palmula culture in the Mexican Central Pacific: spat collection, pre-growth phase (eight weeks), and grow-out phase (six months). We tested natural (shell strings) and artificial (coupelles) collectors placed in contrasting environmental conditions: marine (La Boquita) and estuarine (Cuyutlan). The spat was pre-grown in suspended Australian trays at the two collection sites and under in-land pond conditions. Then, it was pooled under an estuarine environment and in a single lot for the final culture phase in Juluapan lagoon (all sites in Colima, Mexico). Spat collection was higher in coupelles (858.3 ± 175.6 spat coupelle-1) than in shell strings. The number of spat collected (13,062 spat), final pre-growth size (26.5 ± 0.6 mm shell height), and pre-growth survival (94.7%) were higher in La Boquita (marine environment). The final culture phase in Juluapan (estuarine conditions) was successful, recording an average height of 54.2 ± 4.9 mm and average total weight of 30.8 ± 6.9 g after six months of culture, after spat collection and pre-growth periods. We found the largest oyster, S. palmula, ever recorded (shell height 83.3 mm and total weight 59.4 g), and we confirmed that S. palmula has potential for artisanal aquaculture and socioeconomic regional development in the Mexican Central Pacific.

Comparison of fish biological indicators of Clarias gariepinus hybrids grown in ras and pond farming conditions

To improve technologies in the field of commercial cultivation of aquaculture objects and further development of the warm-water aquaculture sector in Russia, we previously undertook breeding methods and approaches to obtain high-quality planting material for a promising commercial object — the African catfish Clarias gariepinus. This article presents, in a comparative aspect, the experience of growing hybrid offspring of African catfish, obtained from crossing two breeds — Mikhailovskaya and Tamanskaya, in a closed water supply system and in a pond farm in the Astrakhan region in the summer. It was shown that hybrid individuals of clariid catfish bred in a pond farm during the feeding period under consideration (from July to September) were characterized by a high specific growth rate and low feed ratio compared to hybrids grown in a recirculation system, respectively, 11.4% versus 9.87% and 0.96 versus 1. Also, based on the results of fishing, over two months of cultivation in a pond farm, hybrids of clariid catfish increased the total biomass by 13 times, while in a recirculating system it increased by 15 times, but the final biomass of fish turned out to be greater when reared in open reservoir (46.875 versus 10.87 kg). It was shown that the final individual mass of hybrid fish cultured in pond conditions was 11.0% higher than the final mass of individuals in the recirculation system. The conducted studies showed that in the climatic conditions of the Astrakhan region (VI fish-breeding zone), a promising direction for aquaculture of African catfish is the feeding cultivation of hybrid juveniles in pond farms. It should be taken into account that in order to obtain marketable fish products (i.e. individuals weighing over 1000 g), it is necessary to use fish seeding material with an average weight of at least 100 g.

Approximate analytical solution of a soil water movement equation under different ponding radii on the basis of numerical simulation

AbstractThis study addresses the problem of 2D soil water movement under ponding radii of 1, 2, and 3 cm. The soil water movement characteristics (shape parameters of the water content profile, ratio of horizontal wetting front to vertical wetting front, relationship between infiltration time and horizontal wetting front, and relationship between infiltration time and cumulative infiltration) under the above three kinds of water ponding radius were analyzed. On the basis of the assumption that the soil wetting body is a semi‐ellipse and the analytical solution of the 1D soil water movement equation at any angle, the approximate analytical solution of the 2D soil water movement equation under ponding conditions is optimized. The function relationships between infiltration time, wetting front, and cumulative infiltration are established. We applied the numerical data simulated by HYDRUS‐3D to validate the parameters in proposed analytical solutions and evaluated the relationships between the wetting front and hydraulic parameters. The results indicate that as the water ponding radius increases, the wetting body and 2D water content distribution becomes larger. When the water ponding radius was 2 cm, the numerical and analytical solution of 1D soil water distribution showed the best comparison results, and the model error was the smallest. The ratio of wetting fronts was linearly increased with the increase of air‐entry suction with R2 = 0.9969.

Характеристика маточного стада несвицького внутрішньопородного типу українських рамчастої та лускатої порід коропа за комплексом продуктивних та репродуктивних показників

Purpose. To provide an assessment of the complex of productive and reproductive parameters of the brood stock of the Nesvych intrabreed type of Ukrainian framed and scaly breeds of carp grown in pond conditions of the Polissia zone. Methodology. The study was conducted at fish farms of Lviv and Volyn regions of Ukraine during 2004-2024. The material for the study was sexually mature carps of the Nesvych type of different ages. The main fish productive and biological parameters were studied during spring valuation according to generally accepted methods in fish farming. Exterior evaluation was carried out according to weight and the main parameters of body structure. Measurements were made with a centimeter tape with an accuracy of 1 mm. Individual weighing of older age groups was carried out on electronic scales PROK VT-150-R1, juveniles - TS-500. Based on the results of the measurements, the main exterior parameters were analyzed and determined — girth, body length to height ratio, head length. The ejaculate volume was determined using an Eppendorf pipette-dispenser with an accuracy of 0.1 cm3. Sperm movement activity was determined using a Zeiss Axiostar plus microscope with a 20x/0.40 phase-contrast objective. The number of spermatozoa in cm3 was calculated using a Macler camera. Calculation of the absolute working fertility was carried out by the weight method, with the calculation of the number of eggs in 1 g and the subsequent determination of the weight of 1 egg. Relative working fertility was defined as the ratio of working fertility to body weight. Findings. The study showed that carps of the Nesvych intrabreed type had exterior parametetrs typical for Ukrainian carp breeds. At the same time, the working fertility of first-time spawning females was in the range of 328.1 - 522.7 thousand eggs, age 6-8 females - 645.7 - 1178.3 thousand eggs, older age groups - 536.2 – 1014.0 thousand eggs. With the average ejaculate volume of 7.6 – 8.3 cm3 in first-spawning males and re-spawning ones 14.9 – 21.3 cm3, active movement of spermatozoa after their activation was observed: 33.1 – 48.6 s and 56.3 - 59.3 s, respectively. At the same time, the working fertility of males was 90.1 - 443.2 billion spermatozoa. The positive response of female Nesvych carp to pituitary stimulation exceeded 95%. Originality. The results of 20 years of selective-breeding work with a representative of aquaculture in the western region of Ukraine are highlighted. In particular, weight dynamics, main exterior and reproductive parameters of brood fish of different ages of brood carp stock of Nesvych intrabreed type of Ukrainian framed and scaly breeds, which were presented and successfully passed the state approval in 2023, are summarized. Practical value. High fish productive and biological parameters of broodstocks of the Nesvych inbred type allow recommending them for use for the purpose of commercial cultivation. Key words: Nesvych carp, intrabreed type, brood stock, exterior, weight, age groups, condition factor fertility, ejaculate volume.

Histological study of ovary of indian major carp Labeo rohita (ham), in pond condition

The scientific management for obtaining high yield of fish production eventually calls for the adequate and indepth study of breeding mechanism. Month wise variations with reference to histomorphological changes in oocytes of a fresh water fish, Labeo rohita (Ham.) have been described. The different stages of oocytes development were examined microscopically. Five stages of oocytes development of Labeo rohita under study were identified. The matured ova were found in the month of May, June and July in the ovary of this fish.. KEYWORDS :Histology, Ovary, Labeo rohita (Ham.)

The results of the continuation of work on the factory reproduction of tench (Tinca tinca L.) in the Saratov region

The present research is a continuation of experimental work on the factory reproduction of tench in the Saratov region. The purpose of our research was to develop elements of biotechnics that optimize artificial reproduction of tench, since the practice of obtaining larvae of this species of fish in fish farms is extremely limited due to the lack of effective methods of its factory reproduction. The objects of research were breeders of tench caught in the Volgograd reservoir and adapted to growing in pond conditions for two years. Two schemes for stimulating puberty of female tench with acetonated carp pituitary gland were used in the work. The first group of females was injected with pituitary solution twice; the second group was planned to be pierced three times by the pituitary gland. After 19 hours, ovulated oocytes were received from 3 females of the second group, stimulated only by two preliminary injections of the pituitary gland. The other two females of this group received eggs after a further three hours. In the females of the first group, who were injected twice, it was possible to obtain ovulated oocytes only in one 21 hours after the permissive injection. Male tench were injected once simultaneously with the pre-injection of females. Methods of de-gluing fertilized eggs with the help of proteolytic enzymes alkalase and neutrase have been studied. The solution of the enzyme alkalase at a concentration of 3 ml/liter of water and an exposure of 1 minute showed a well-pronounced de-gluing activity, followed by incubation of fertilized eggs with a larval yield of up to 80%. The second batch of ovulated oocytes was desaturated with a neutrase solution at a similar concentration and exposure as alkalases. The results of de-gluing were unsatisfactory, since the eggs were constantly glued to the walls of the flask of the Weiss apparatus.

Epibiotic ciliate communities on the crayfish Procambarus (Austrocambarus) sp. cultivated in a rustic aquaculture in southern Mexico

Rustic aquaculture systems represent a sustainable production alternative in the world, providing appropriate conditions for the establishment of epibiotic ciliates on crayfish. However, the impact of epibiotic ciliates on the aquaculture production has been insufficiently studied hitherto. The objective of this work was to identify the epibiotic ciliates on the surface of the crayfish Procambarus (Austrocambarus) sp. and analyze whether there is any correlation between seasonality and environmental conditions in an artificial pond in Chiapas, Mexico. The crayfish were collected during dry and rainy seasons to investigate their ciliate epibionts. Some physical and chemical parameters of the sampled water were measured and correlation matrix analyses were applied to detect possible relationships between the presence of ciliates and environmental parameters. Thirteen species belonging to the subclasses Peritrichia and Suctoria were identified. Significant differences were found for some environmental parameters and species recorded in both seasons. The present data could help to better understand the relationship bewteen the epibiotic ciliate community on crayfish and some environmental parameters in aquaculture systems.

LAND UTILIZATION AND DEVELOPMENT OF VANAME SHRIMP CULTIVATION IN COASTAL AREA, KUBU SUB-DISTRICT, KARANGASEM REGENCY, BALI

The pond land suitability is the most important things in shrimp farming to maintain production and ensure the development of aquaculture businesses. This research aims to determine the outland suitability of the coastal area of Karangasem Regency, evaluate the distribution pattern of cultivation activities and identify regional development factors. This research was a descriptive qualitative study where the analysis results related to mapping of land uses studies are presented descriptively. The data used in this study consisted of primary data: (i) physical-geographic of coastal areas; (ii) public aspirations in coastal areas, and secondary data traced from BPS, Ministry of ATR/BPN Office of Karangasem and PUPR Service Karangasem Regency. The results of this research showed that the spatial analysis of the land suitability in Kubu sub-district showed the land potential with high suitability is 1,009.46 ha; moderate suitability land level is 1,894.01 ha; for coastal areas that do not have potential or are not feasible for developing shrimp water ponds is 799.67 ha. The Kubu sub-district is a center of the shrimp water ponds development in Karangasem Regency, Bali. The existing condition of shrimp water ponds in Kubu sub-district are spread over 3 villages: Sukadana with 20.36 ha; Tianyar in 1,32 ha and West Tianyar with 0.47 ha in area. Through the analysis of internal and external factors of shrimp pond development activities in Kubu Subdistrict, showed that the coastal area of Kubu Subdistrict is very feasible to develop Vannamei shrimp.

Benefit of the nutritional and mineral composition of sea lettuce from a traditional salina: Implications for human consumption

The proximal composition and its seasonal variation of the green seaweed Ulva sp. harvested in a traditional saline (earthen ponds used for marine salt extraction) from Cadiz Bay (Southern Spain) was evaluated. Ulva sp. was also collected in a reference location within the Bay in order to compare and evaluate the effects of the particular characteristics of the saline in the composition of the macroalgae. Moisture, protein, lipid, ash, carbohydrate, fiber and macro- (Na, K, Ca, Mg), micro-mineral contents (Fe, Zn, Cu) and heavy metals (As, Cd, Co, Cr, Hg, Ni, Pb, Sn) of harvested biomass samples as well as environmental parameters of seawater (temperature, salinity, pH, DO, NH4+, NO3−, NO2− and PO43−) were measured. The results showed that Ulva sp. from the earthen ponds in the traditional salina was a better source of proteins, lipids, K and Mg, highlighting in summer with values of 27.54 % versus 6.11 %; 6.71 % versus 3.26 %; 26.60 mg g−1 versus 14.21 mg g−1 and 23.13 mg g−1 versus 17.79 mg g−1, respectively. It also had Na/K and Ca/Mg ratios of less than one, suggesting a healthy food source. Considering the Commission Recommendation (EU) 2018/464 as a working reference, Ulva sp. did not exceed the limit of toxic metals for human consumption.A season and site-season significant interaction on the composition of the seaweeds was observed. The proximal and mineral composition of Ulva sp. was influenced by the special features and environmental conditions of the earthen ponds. Hence, significant differences were observed in the macroalgae collected in the earthen ponds in summer and autumn, in contrast to the winter and spring samples, whose characteristics were similar to those from the inner bay. The closure of the lock-gates in summer to favor the production of salt significantly modified the environmental characteristics of the saline, affecting the physiological capacity of Ulva sp. to assimilate and storage nutrients, and therefore its tissue composition. As a consequence, the highest contents of lipid, ash, Ca, K, Mg and Fe were estimated in the macroalgae.

Оцінка товарних кондицій помісей першого покоління антонінсько-зозуленецьких та галицьких рамчастих коропів

Purpose. To characterize age-1+ hybrids obtained from the crossing of Galician framed carp (GFC) and Antoniny-Zozulenets framed carp (AZFC) according to a set of commercial conditions in comparison with parental lines. Methodology. The objects of the study were age-1+ hybrids of the reciprocal crossing of Galician and Antoniny-Zozulenets carps grown in pond conditions of the “Karpatskyi Vodogray” LLC. The study was conducted at the end of the growing season according to methodological recommendations. The body of the experimental carp for analysis was divided into its constituent parts: scales, fillet with skin, entrails, fins and bones. In the process of work, blood was removed, its weight was attributed to the entrails. The head was separated from the carcass by breaking it off between the occipital bone and the first vertebra.Each part was weighed separately and presented as a percentage of the total body weight. Findings. The obtained results showed that the yield of the main part of the fillet with skin in crossbred groups of age-1+ carp was 48.7–52.0% and was higher compared to purebred offspring.In comparison with the original maternal line, crossbred age-1+ ♀GFC ×♂AZFC had a higher index of relative fillet weight by 3.15%, and the similar 1.6% superiority was observed in crossbreds ♀AZFC × ♂GFC. At the same time, with an increase in the average weight of age-1+ by 28.9–68.6% in the 2023 studies, the relative weight of the carcass increased by 2.4–11.0%. At the same time, the relative weight of the head decreased by 5.3-6.1%, and the relative weight of the entrails increased by 0.7-4.7%. In general, the inedible part of the studied groups of fish was in the range of 27.2–32.4%. In terms of the yield of fillets per 1 ha of fattening pond, the superiority of interbreeding groups of age-1+ was 31.5–62.7%. The obtained results indicate the expediency of their use as new highly productive commercial lines in pond farms of the Polissiya zone. Originality. For the first time, a comparative analysis of the nutritional value parameters of age-1+ carp from reciprocal crossings of Galician and Antoniny-Zozulenet framed carp and the original pure lines cultivated in the conditions of Ukrainian Polissiya was carried out. Practical value. The obtained results will complement the studies of previous years and will allow providing recommendations on the use of these hybrids for commercial cultivation in the Polissiya zone of Ukraine. Keywords: carp, weight, market conditions, edible and inedible body parts.

Identification of soil properties influencing primary productivity of fish ponds under red and lateritic soil zones

Aim: The present study aimed to identify the key soil factors influencing the primary productivity of water in the fish ponds situated under low productive red and lateritic soil zones. Methodology: General properties of fish pond soils (n=42) from different red and lateritic soil zones of West Bengal, India were determined along with the gross primary productivity (GPP) values of corresponding pond waters. All the soil properties were correlated with GPP values and the soil factors which were significantly correlated with GPP of pond water were further used for step down regression analysis with regard to GPP.This helped to develop a minimum data set of the key soil factors which showed maximum influence on GPP. The efficiency of the regression equation, generated with the critical soil parameters, in predicting the GPP values of other ponds was also assessed through a study on the variations in calculated and on-farm GPP values of eight fish ponds. Results: Among all the studied soil properties, pH and availability of three major nutrients viz. N, P and K were observed to contribute 84.15% variations in gross production of primary fish food organisms in these pond environment. Of these 4 soil properties, again, pH and available P values of the pond soils appeared to be more important. A regression equation was also developed to predict the GPP of such pond water using soil pH and available P values only. This equation showed a precision range of 83.0 to 99.7% and was found to be statistically at par with the GPP values observed under actual pond condition. Interpretation: High efficiency in predictability of pond GPP values using the minimum data set of two key soil factors viz. soil pH and available P indicates that proper management of these productivity attributing soil properties will be particularly helpful to improve the primary productivity levels of the predominantly low yielding fish ponds under the red and lateritic soil zones. Key words: Fish ponds, Minimum data set, Productivity attributes, Red and lateritic soil zones, Soil factors

Relationship Between Abundance of Clamydomonas spp and Chlorella spp on Clinical Performance of Red Tilapia Oreochromis niloticus in Silvofishery Ponds

Abstract Chlamydomonas spp. and Chlorella spp. are plankton genera that can be used to determine the level of balance in the aquatic environment. The purpose of this study is to determine the abundance of plankton Chlamydomonas spp. and Chlorella spp. and its relation to the clinical performance of red tilapia in silvofishery ponds. The research method used is an ex post facto causal design with random sampling. The results showed that the water quality in the silvofishery ponds was very good, except for the nitrate parameters of 0.00-1.50 mg/L and salinity of 2-11 gr/L, which exceeded the quality standards. In the silvofishery ponds, 5 plankton classes were found, namely Chlorophyceae, Cyanophyceae, Chrysophyceae, Protozoa, and Dinophysis, consisting of 15 genera. The dominant class Chlorophyceae had an abundance of 2.88E+06 cells/ml. The class Chlorophyceae is dominated by Chlorella spp. (2.63E+06 cells/ml) and Chlamydomonas spp. (2.20E+05 cells/ml). The abundance of Chlamydomonas spp. in silvofishery ponds is closely related to phosphate solubility (0.988). Based on observations of clinical symptoms on the eyes, gills, and fins of fish, no disease infections or physical abnormalities were found in the fish cultured in silvofishery ponds. Fish tend to live well with a growth rate of 0.44 g/day. The aquatic ecosystem of the silvofishery pond, which is dominated by the plankton Chlorella spp. and Chlamydomonas spp., had a good effect on the performance and condition of the farmed fish. This study concludes that the abundance of Chlamydomonas spp. and Chlorella spp. was very dominant compared to other plankton genera. The presence of Chlamydomonas spp. and Chlorella spp. illustrates good and stable environmental conditions in silvofishery ponds, followed by no clinical signs of disease infection in the fish reared during the study period.

EVALUATION OF DIFFERENT STOCKING DENSITY OF SMALL INDIGENOUS FISH PABDA WITH CARP POLYCULTURE SYSTEM

An experiment on the polyculture of carps with high valued small indigenous fish species (SIS) Pabda (Ompok pabda) was carried out for 152 days to evaluate the production performances of carp and pabda in some on-farm pond conditions in three Upazila of Jhenaidah district. Three stocking densities of Pabda were T1500, T2600, and T3-700 fish per decimal where released, carp density was the same among the treatments at 246 nos/33 decimal. Fish was fed with commercial (sprectahexa, mega) pelleted feed at the same rate at the different stages of Pabda (0.66-50 gm BW @ 20%-4% twice a day respectively). The weight gain of Pabda was 40.965 ± 0.04, 35.17± 0.11 and 30.99 ± 1.17 g in T1, T2, and T3 treatments, respectively. The production levels showed significant difference (P<0.05) among the treatments. The SGR (%) of Pabda was 2.76 ± 0.0006, 2.66 ± 0.002 and 2.58 ± 0.024 in T1, T2, and T3, respectively that showed a significant difference (P<0.05) among the treatments. The weight gain of carp was 1177.24 ± 30.87, 1150± 0.001, 1154.85 ± 3.43 in T1, T2, and T3, respectively, which was also significantly different (P<0.05) when ANOVA was performed. The water quality parameters like transparency and dissolved oxygen in the treatments showed significant differences (P<0.05) except temperature, pH, and ammonia nitrogen. The results of the present study demonstrated that the fishes showed better growth, survival, and production in the low stocking density of Pabda in T1 treatment.

Dynamics of change in the number of amphibian larvae in pond conditions and factors determining it in the central part of Belarus

The aim of the work is to study the influence of factors of abiotic and biotic origin on abundance, growth rate and development of amphibian larvae in natural conditions.The scientific novelty of the work lies in studying the degree of interaction of amphibian larvae with each other and with invertebrate predators, their interaction in natural conditions. The main part of the work contains a literature review, the work methodology and the result description.In conclusion, it was noted that under natural conditions, the magnitude of impact of predators on the number of amphibian larvae is much lower than it has been previously thought; they are not able to provide a significant function of regulating the number of tadpoles. Abiotic environmental factors, being within the optimum limits, do not affect the mortality of larvae, and food in natural water bodies is not a factor limiting abundance. The most intensive death of larvae occurs in the early larval development stage. Despite a low overall density of larvae in a natural water body, most amphibian larvae are periodically exposed to metabolites and are affected by the “group effect”. This is expressed in the inhibition of growth and development of individuals, the death or decrease in the decline in the viability of the most sensitive individuals, and also increases the likelihood of their death from other factors.

Morphological analysis of resorption and degenerative processes in gonads of fishes — representatives of different families in reservoirs Dagestan part of the Middle Caspian Sea

In recent decades, the vulnerability of the Caspian Sea ecosystem has been observed due to large-scale anthropogenic impact. Due to the limited number of studies on resorption and degenerative processes in fish gonads, it was important to evaluate these regularities in commercial fish species — representatives of different families in the water bodies of the Dagestan part of the Middle Caspian Sea. In the process of our own research and analyzed literature data, the peculiarities and character of resorption passage when it is of mass character were revealed and the reasons causing it were established. In addition, the phases (stages) and conditions necessary for this process, its duration and irreversibility were studied. The biological significance of resorption has been established. Disturbances revealed in the external morphology of germ cells may be a predictor of profound changes in their structure and function. To clarify and elucidate the possibility of participation of individuals of the analyzed fish species in the spawning process with abnormal types of gonads, it is necessary to conduct a more detailed study of the sex glands at different levels of their organization, including cellular, tissue and organ levels. All the obtained factual data, regularities and revealed peculiarities in the reproductive processes in the studied species with different biology provide an opportunity for further scientific knowledge of all parts of the reproductive cycle in fish in different ecological conditions. We consider the revealed peculiarities of functioning of reproductive systems, mechanisms of adaptation of fishes to different conditions of existence as significant and necessary for solving many theoretical questions — in the field of morphofunctional and ecological analyses of evolutionary process, as well as such urgent practical problems as obtaining artificially full-fledged eggs and milk for fish breeding in pond conditions; for biologically justified exploitation of fish resources in natural reservoirs, which provide fish with high fecundity.

Rancang Bangun Aplikasi Pemeliharaan Ikan Koi Berbasis Android dengan Menggunakan Teknologi IoT

In the maintenance of Koi fish, the quality of the pond environment and water plays an important role in the success of Koi fish care. Koi fish or commonly known by another name Cyprinus Rubrofuscus is one type of freshwater ornamental fish that is very sensitive to pond environmental conditions and water quality. At this time many people want to keep koi fish as pets or even make koi fish as a business. Koi fish is one of the difficult fish to maintain because it requires extra monitoring of the pond conditions and water conditions of the koi fish pond. The difficulty of monitoring pond conditions and water conditions in koi fish ponds presents an idea to develop an Android-based Koi Fish Monitoring and Maintenance application using IoT technology in its design. The existence of this application aims to analyze the application of Internet of Things (IoT) technology to help the maintenance and care of koi fish. By using the IoT technology study method to monitor the condition of koi fish care automatically, it is hoped that this application can be able to facilitate accurate monitoring of pond and water conditions.