Aquaculture Production Research Articles

Design and implementation of a shrimp pond monitoring system using Internet of Things

In 2020, the volume of fishery exports will reach 1.26 billion kilograms (kg) with a value of US$ 5.2 billion. Shrimp became the commodity with the most exports, namely 239.28 million kilograms with a value of US$ 2.04 billion. In 2020 shrimp aquaculture production in Indonesia reached 911.2 thousand tons, shrimp also contributed to the total export volume of fishery products by 18.95%. Vaname shrimp production is also targeted to reach 2 million tons in 2024, some of which will be for export. In an effort to achieve this target, a system is needed that is capable of monitoring and controlling shrimp ponds using the Internet of Things (IoT). Because the monitoring process that is carried out traditionally will take time and be less efficient. Therefore, it is necessary to develop a system for monitoring and controlling shrimp ponds automatically using IoT. Sensors and microcontrollers are used to read and control input and output data such as pH, temperature, salinity, turbidity, light intensity, water level, and actuators for filling and draining pumps. This system will also be equipped with an expert system to be able to perform data analysis of measured parameters. This research was carried out within 2 years. In has been carried out the development and manufacture of hardware on the monitoring and control system. In the second year, hardware and software integration will be carried out to be able to monitor, control, and analyze data as decision support and implementation in the actual system. The purpose of this research is to design and build a monitoring and control system for shrimp ponds based on the Internet of Things.

Production, Diversity, and Distribution of Aquaculture Commodities in Tuban, Indonesia

Graphical Abstract Highlight Research Tuban (Indonesia) aquaculture commodities are surveyed. Aquaculture diversity in Tuban are consisted of 5 fields, namely rice field ponds, floating net cages, freshwater ponds, and brackish aquaculture ponds Aquaculture commodities in Tuban consist of 11 families and 14 species of the main aquatic production. Cyprinus carpio or common carp is one of the commodities cultivated in four different aquacultures. Abstract Fishery is a sector expected to overcome the food crisis. Indonesia is one of the leading countries in high volumes of fishery production in most of its areas, including the Regency of Tuban in East Java Province. The area of Tuban Regency is 1,839.94 km2 with the coastline covers 65 km and a sea area of 22,608 km2. This study aims to provide information regarding aquaculture production, diversity, and distribution in Tuban. This study used a survey method in collecting fishery commodity data directly from aquaculture areas. The results of this study showed that the highest production came from the brackish water with a value of 32.46% (13,561.79 tons), followed by rice field pond (27.79% or 11,612.45 tons), freshwater pond (25.76% or 10,764.62 tons), floating net cage (13.97% or 5,836.59 tons), and marine (0.1% or 5.67 tons). Aquaculture biodiversity in Tuban consisted of 11 families and 14 species of the main aquatic produces, such as Cyprinidae (Cyprinus carpio, Barbonymus gonionotus, Parastromateus niger), Clariidae (Clarias bathracus), Pangasiidae (Pangasianodon hypophthalmus), Penaeidae (Penaeus monodon, Litopenaeus vannamei), Channidae (Channa striata), Cichlidae (Oreochromis niloticus, Oreochromis mosammbicus), Osphronemidae (Osphronemus gourami), Serranidae (Epinephelus), Lutjanidae (Lutjanus), and Chanidae (Chanos chanos). Cyprinus carpio or common carp is fish cultivated in four different aquacultures, namely rice field pond, floating net cages, freshwater ponds, and brackish aquaculture ponds. Unfortunately, the diversity and production of marine aquaculture has not been improved even though Tuban has large marine areas.

Seasonal dynamics and ecological risks of organochlorine pesticides in Kafrelsheikh-Egypt: Implications for aquatic ecosystems and public health

Kafrelsheikh, situated in the middle of the Nile Delta, significantly contributes to Egypt's aquaculture and agriculture sectors. However, the local use of organochlorine pesticides (OCPs) in agriculture is often a source of OCP residues in associated drainage waters, which may threaten aquatic ecosystems. These pesticides persist in local water bodies, jeopardizing aquatic ecosystems and potentially impacting human health. This comprehensive study assessed the seasonal variations of 17 OCPs in both water sources and Nile tilapia across eight fish farming locations in Kafrelsheikh. Using gas chromatography coupled with mass spectrometry (GC-MS), we detected OCP concentrations in water that varied seasonally where winter recorded the highest levels at 22.5 ng/mL and, summer showed the lowest levels at 6.2 ng/mL. Despite water samples occasionally showing risk quotients (RQs) greater than 1, indicating a potential threat to aquatic life, the OCP levels in Nile tilapia were sufficiently low, with target hazard quotients (THQ) below 1, suggesting no significant risk for human consumption. The research highlights a pressing need for regular environmental monitoring and stricter regulatory control over pesticide use to protect aquatic life and ensure the safety of aquaculture products. These findings provide a critical basis for policy-making, aimed at balancing agricultural productivity with environmental sustainability in regions heavily dependent on both.

Sampling time for different matrices in stress assessment of farmed Atlantic salmon post-smolt

The sustainability of commercial aquaculture production depends critically on prioritizing fish welfare management. Besides monitoring welfare parameters such as fish behaviour and water quality, fish stress level can also provide a reliable measure of the welfare status of farmed fish. Cortisol and 5 of its metabolites (5β-THF, cortisone, 5β-DHE, 5β-THE, β-cortolone) were previously identified by the authors as suitable stress biomarkers of farmed Atlantic salmon. Based on this knowledge, the present study aimed to investigate the time-related dynamics of these metabolites in plasma, skin mucus, bile and faeces over a 72 h- period. The objective was to determine the optimal sampling time for each matrix and to understand the clearance pathway of these metabolites following stress. An experiment was carried out using a total of 90 Atlantic salmon with an average weight of 438 (±132) g. The average sea temperature was 6.9 °C during the experimental period. A control group of 10 fish was first collected before the remaining 80 fish were submitted to a stress of netting and subsequent relocation into two separate cages. From each of these two stress groups, 10 fish were sampled at 1 h, 2 h, 4 h, 6 h and 12 h, 24 h, 48 h, 72 h after the stress event respectively. The concentrations of cortisol and its metabolites were measured at each of the sampling timepoint. The results demonstrated that plasma cortisol metabolites reached the highest concentration 4 h after stress and remained elevated despite the slight decrease for the remaining timepoints. The peak level was observed at 12 h post-stress in skin mucus and 24 h in bile and faeces. The findings suggest that these timepoints are the optimal for sampling Atlantic salmon post-smolt following stressful events in acute stress studies. Furthermore, the results reveal that analysing cortisol and its metabolites, both in free and conjugated forms, rather than free cortisol provides greater flexibility as their concentrations are less affected by sampling procedure. This study confirms the appropriateness of skin mucus and faeces as less-invasive sample matrices for fish stress evaluation and provides a basis for further developing low invasive tools for monitoring the welfare of farmed salmonid.

Research on and application of low-temperature calcination on waste Taiwanese hard clam shell during Taiwanese hard clam aquaculture

This study uses a circular economy-regenerative value addition approach. Pre-treated waste clam shells were calcined at a low temperature (about 300 °C) and then crushed into clamshell powder. Taiwanese hard clam shell (THCS) powder and commercially available calcium carbonate products, such as low-temperature calcined oyster shell (OS) powder, slaked lime, and calcium carbonate, were compared experimentally, and the safety of THCS powder was determined. In the safety evaluation, the Vibrio-like bacteria test results showed that no colony growth was found for the low-temperature-calcined THCS powder, indicating that it did not contain Vibrio-like bacteria. Tolerance test results showed that high-dose slaked lime will cause high Taiwanese hard clam mortality, and the survival rates of other groups were all 100%. In addition, slaked lime had the most significant effect on increasing the water pH. OS powder had the greatest effect on increasing the calcium ion concentration in the water, followed by THCS power. The aquaculture benefit-related experimental results showed that the low-temperature calcined OS powder and THCS powder groups had the most favorable performance in terms of Taiwanese hard clam growth rate, shell weight, and shell thickness. This study used different calcium carbonate products as additives in Taiwanese hard clam aquaculture ponds and observed growth differences between the different groups. These results indicated that the low-temperature calcination of THCS in Taiwanese hard clam aquaculture can effectively replace the commonly used OS powder, slaked lime, and calcium carbonate products in traditional aquaculture. Furthermore, it can effectively solve the problem of THCS waste accumulation, promote environmental beautification, create a circular economy and aquaculture application value, and conform to the economic benefits of aquaculture.

Underwater Backscatter: What is its Practical Communication Distance?

Recent years have seen mounting interest in low-power, distributed subsea internet-of-things (IoT) networks because of their potential in environmental, industrial, and defense applications [1,2]. Energy-efficient ocean IoT networks can enable long-term sensing of ocean variables (temperature, pH, pressure, salinity, etc.) to create more accurate climate and weather prediction models and monitor the impact of climate change on the ocean [3]. Similarly, low-cost and efficient ocean IoT networks can help boost the growth of the world's blue economy by enabling active monitoring of marine infrastructures ranging from oil/gas pipelines to underwater tunnels [4]. Real-time distributed underwater sensor networks can help boost aquaculture (seafood farm) production by monitoring the farm vitals (water temperature, dissolved nutrients, pH, etc.) and detecting environmental hazards (such as harmful algae blooms) early [5].

The impact of food production on ecological footprint in Turkey: an analysis across agriculture, livestock, and aquaculture

AbstractThe ecological footprint (ECF), which has been frequently examined recently, offers a comprehensive analysis of the environment and has started to be used in Turkey. However, although it is a significant area of study in the world, food production, that raise the ECF the most, has not been the subject of much research in Turkey. In the present analysis, food production’s impacts on the ECF in Turkey are analyzed with yearly statistics for the period 1961–2018. Within the frame of this analysis, both food production as a whole and agriculture, livestock, and aquaculture production, which are the components of food, were analyzed individually. In this context, four different models were constructed, and the Autoregressive Distributed Lag method was used to analyze. According to the outcomes of the analysis, food, agriculture, and livestock production raise the ECF while aquaculture production diminishes. The largest coefficient among the three sub-sectors belongs to the agriculture sector. In addition, while the use of fertilizers, agricultural land, GDP, population, and life expectancy at birth increases the ECF, the age dependency ratio decreases, and the effect of rural population differs in the models.

Metagenomic dissection of the intestinal microbiome in the giant river prawn Macrobrachium rosenbergii infected with Decapod iridescent virus 1

Microbiome in the intestines of aquatic invertebrates plays pivotal roles in maintaining intestinal homeostasis, especially when the host is exposed to pathogen invasion. Decapod iridescent virus 1 (DIV1) is a devastating virus seriously affecting the productivity and success of crustacean aquaculture. In this study, a metagenomic analysis was conducted to investigate the genomic sequences, community structure and functional characteristics of the intestinal microbiome in the giant river prawn Macrobrachiumrosenbergii infected with DIV1. The results showed that DIV1 infection could significantly reduce the diversity and richness of intestinal microbiome. Proteobacteria represented the largest taxon at the phylum level, and at the species level, the abundance of Gonapodya prolifera and Solemya velum gill symbiont increased significantly following DIV1 infection. In the infected prawns, four metabolic pathways related to purine metabolism, pyrimidine metabolism, glycerophospholipid metabolism, and pentose phosphate pathway, and five pathways related to nucleotide excision repair, homologous recombination, mismatch repair, base excision repair, and DNA replication were significantly enriched. Moreover, several immune response related pathways, such as shigellosis, bacterial invasion of epithelial cells, Salmonella infection, and Vibrio cholerae infection were repressed, indicating that secondary infection in M. rosenbergii may be inhibited via the suppression of these immune related pathways. DIV1 infection led to the induction of microbial carbohydrate enzymes such as the glycoside hydrolases (GHs), and reduced the abundance and number of antibiotic-resistant ontologies (AROs). A variety of AROs were identified from the microbiota, and mdtF and lrfA appeared as the dominant genes in the detected AROs. In addition, antibiotic efflux, antibiotic inactivation, and antibiotic target alteration were the main antibiotic resistance mechanisms. Collectively, the data would enable a deeper understanding of the molecular response of intestinal microbiota to DIV1, and offer more insights into its roles in prawn resistance to DIVI infection.

Potential plasma biomarkers for the onset of heart and skeletal muscle inflammation from Piscine orthoreovirus-1 infection in Atlantic salmon (Salmo salar)

Biomarkers that give quantifiable information about disease development are valuable diagnostic indicators providing opportunities to thwart adverse outcomes through timely detection and initiation of countermeasures. Whereas human medicine already relies extensively on biomarker analysis, their application in the diagnostics of fish diseases is still at a tentative beginning. However, the increased utilisation of broad-range analytical approaches such as untargeted proteomics enhances the chances to discover changes in the levels of proteins, which are connected to fish health and could serve as novel biomarkers. In the present study, proteomic analysis accompanied by biostatistical data processing was employed with the aim of identifying plasma biomarker candidates for the onset of heart and skeletal muscle inflammation (HSMI) caused by Piscine orthoreovirus (PRV)-1 infection in Atlantic salmon. HSMI is a common viral disease and threat to fish welfare and productivity in Norwegian aquaculture, so that the early detection of HSMI development would allow a timely intervention to limit the damage. In the search for biomarker candidates, salmon plasma was sampled five and eight weeks after a PRV-1 cohabitation challenge experiment and from adequate control fish, and analysed by mass spectrometry-based proteomics. The proteome dataset contained 695 proteins with >90% probability of correct identification according to the set cut-off criteria for peptide quality. Time- and condition-related differences in protein abundance levels were revealed by multivariate analysis. Comparison of the proteins identified as significant using three different biostatistical models resulted in a short list of four potential biomarkers: galectin-3-binding protein (Gal-3BP), fucolectin-6, urokinase plasminogen activator surface receptor and ryanodine receptor 3. The physiological functions described for these proteins in mammals designate them as interesting indicators of inflammatory diseases also in other species, such as PRV-1 pathogenesis in salmon. In situ-hybridisation targeting Gal-3BP and PRV-1 mRNA in heart tissue sections from the same challenge trial showed a significant upregulation of Gal-3BP mRNA in infected salmon hearts as compared to controls, supporting the findings of the proteomic analysis and suggesting a role in the onset of heart- and skeletal muscle inflammation.

A review of dynamic optimization in aquaculture production economics

AbstractDynamic optimization (DO) has been applied to aquaculture industry to determine optimal management strategies of aquaculture production systems. Optimal control of feeding, optimal stocking successions, and harvesting time among other factors has been studied. This work shows a review of the application of optimal control theory (OCT) and dynamic programming in economics and management of aquaculture. The Pontriagyn's maximum principle and the Bellman's optimality are the most commonly used mechanisms to solve control problems that optimize the producer's benefit or cost. Recently, model‐based predictive control has also been applied. Such tools have been used in aspects involving the design, planning, and monitoring of variables relevant to the optimal management of the culture system. It was found that in aquaculture there is low scientific productivity in the application of DO in bioeconomic models. In this review, an example of OCT applied to the control of feeding of farmed tilapia using a bioeconomic model is shown. DO represents a useful tool for optimal decision‐making and this review discusses the implications of the use of DO in aquaculture and recommendations for its use in the future.

Recovery of nutrients from fish sludge to enhance the growth of microalga Chlorella sorokiniana CMBB276

Intensive aquaculture production generates large amounts of sludge. This waste could be considered as a potential source of nutrients that can be recovered and utilized. Little attention has been paid to nutrient recovery from fish sludge. In this study, bioconversion of sludge was evaluated in lab scale under anaerobic (AN), facultative anaerobic (FA) and aerobic (AE) conditions. After 40 days of fermentation, AN recovered the highest values of dissolved total nitrogen (82.7 mg L−1), while AE showed the highest dissolved total phosphorus (11.8 mg L−1) and the highest reduction of total suspended solids (36.0 %). Microbial analysis showed that AN exhibited a distinct bacterial community than that of FA and AE. Furthermore, C. sorokiniana grown in AN effluents collected after 12 days of fermentation achieved the highest biomass production (1.96 g L−1). These results suggest that AN has the best potential to recover nutrients from sludge for production of C. sorokiniana.

Construction and reflections on the disease prevention and control system of aquatic organisms based on management perspective

Disease prevention and control are a crucial aspect of fishery management, as they ensure the sustainability of aquacultural systems. With a specific focus on Shandong Province, China, this study outlines the occurrence of diseases in aquatic organisms. It summarizes dynamics that drive disease prevention and control and supports technology, work mode, and emergency prevention and control. In addition, this study also delves into the role of epidemic prevention and control institutions, the upgrading of the social service of disease prevention systems, and insufficient technical support for new species and models. Overall, the findings outlined in this study are intended to achieve the following aims: enhance organizational management of disease prevention and control, standardize the implementation of social services, improve research into prevention and control technologies, and highlight the importance of information technology in disease prevention and control. Based on practical aquaculture production, our aim is to comprehensively analyze the situation of the construction of a disease prevention and control system, strengthen guidance on epidemic prevention technologies, establish a robust animal epidemic prevention system, and propose development strategies, serving as a reference for competent authorities to enhance the disease prevention and control of aquatic organisms.

Effect of Covid-19 Pandemic on Shrimp Farming at Navsari, Gujarat, India

The lockdown on account of the Coronavirus disease 2019 (COVID-19) adversely impacted the food production sector including aquaculture globally. Unfortunately, it coincided with the major shrimp farming season in India which contributes 60% of the national annual shrimp production hence the impact was substantial. Shrimp farmers follow the different management practices in shrimp farming operations like seed, feed, probiotics, medicine, disruptions in the supply chain, transportation, harvesting and marketing. Therefore, the objective of present study was to find out the impact of COVID-19 pandemic on shrimp farming sector in Navsari (Gujarat). These findings are depicted that management practices of the shrimp farming in study area was disturbed and huge economic losses was faced by the shrimp farmers during pandemic situations. It is suggested that technical and financial assistance for safe, sufficient and hygienic supply of seed, feed, probiotics, chemicals, medicines and probiotics by the government agencies should be ensured which help to shrimp enhance the aquaculture production and survive of shrimp farmers. The result of present study is also helpful for the government authorities to develop policies and execution of the plans during such pandemic condition for shrimp farmers that can prevent the production loss and sustain the shrimp farming industry.

Submerged plant-biochar composite system exhibits effective control over residual organic pollutants in the benthic organisms of aquaculture ponds

As of now, submerged plants and biochar have demonstrated significant benefits in aquaculture pond sediment remediation. However, there is limited research on the synergistic effects of biochar and submerged plants in mitigating hydrophobic organic contaminant (HOC) accumulation in aquaculture benthic organisms and in controlling the nutrient (nitrogen and phosphorus) levels in aquaculture water. This study assesses a submerged plant-biochar system's efficacy in removing HOCs from simulated freshwater aquaculture ponds. Vallisneria natans was planted in sediment with varying levels of wheat straw biochar, while Corbicula fluminea served as the targeted benthic organism. The bioaccumulation experiment identified the optimal biochar ratio for the Vallisneria natans-biochar system in controlling HOCs in aquaculture products. Analyses included final accumulation concentrations in benthic organisms, changes in freely-dissolved concentrations in aquaculture sediment, and a mass balance calculation to explore key factors in their removal from the system. Results indicated that the Vallisneria natans-1.5% biochar composite system achieved optimal control of HOCs in sediment and aquaculture products. Biochar addition to the sediment in the composite system demonstrated a “promotion with low addition, inhibition with high addition” effect on Vallisneria natans growth. Notably, the addition of 1.5% biochar (VN1.5 group) significantly promoted the growth of Vallisneria natans leaves and roots. Comparing the final pollutant proportions in different environmental media, concentrations in water (0.20%–1.8%), clam accumulation (0.032%–0.11%), and plant absorption (0.10%–0.44%) constituted a minimal portion of the overall pollutant load in the system. The majority of pollutants (24%–65%) were degraded in the aquaculture environment, with microbial degradation likely playing a predominant role. Bacterial phyla, particularly Proteobacteria and Firmicutes, were identified as potential direct contributors to pollutant degradation in the Vallisneria natans-biochar system.

Nutritional and Organoleptic Characteristics of Sausage Based on an Autochthonous Ecuatorian Fish, Old Blue (Andinoacara rivulatus).

The consumption of fisheries and aquaculture products has been increasing in recent decades, and it is necessary to strike a balance between production and sustainability in aquaculture; this is essential homework to support the demand for human food. This study aimed to investigate the sensory and nutritional characteristics of a sausage made from the fillet of the native fish Old Blue (Andinoacara rivulatus) to stimulate the local economy. A multifactorial A*B*C design was used, with Factor A being rearing systems (wild and farmed), Factor B being types of protein (quinoa meal and soybean meal), and Factor C being lipids of animal (pork fat) and vegetable (sunflower oil) origin. Highly significant differences were observed in all formulas, according to Tukey (p < 0.05). The highest protein percentage was with soybean flour at 11.24%, while quinoa flour had 10.80% of the product. In sensory characteristics, the best attributes were for texture in the mouth with a hedonic scale from 0 to 5, with 4.2 firmness being mostly acceptable, odor at 4.5, the aromatic attribute with the highest and best value, and color was the clearest at 4.3 acceptability. The flavor was 4.3, mostly more pleasant according to the tasters. The yield of farmed fillets was 23.16% compared to wild 13.89%, and the balance of sausage yield was 393 g with a yield of 76.33% of the total weight. Microbiological analysis of the sausage with the native species showed the absence of pathogenic microorganisms. A commercial shelf life of 30 days was also established for the sausage, demonstrating an added value through this processing, allowing its exploitation in areas further away from the fishing sites and, thus, a greater possibility of social development in the area.

The impact of aggregated and disaggregated fisheries production and licensed fishermen on fishing grounds footprint: A time series analysis

This study has examined the factors of fishing grounds footprint in Malaysia during 1961–2018, which has been used as the indicator of environmental degradation. The main contribution of this paper is that we have considered the role of aggregated and disaggregated fisheries production on pollution in the fishing industry. Another contribution of this study is that the environmental impact of activities of licensed fishermen has been examined. The results suggest that the total fisheries production and its components- capture fisheries production and aquaculture production generate an increase in fishing grounds footprint in Malaysia. The results suggest that an increase in total licensed fishermen facilitate an increase in fishing grounds footprint. There is mixed evidence on the impact of local fishermen on fishing footprint. The results indicate that an increase in foreign fishermen facilitate an increase in fishing grounds footprint. The results suggest mixed evidence for Environmental Kuznets Curve (EKC) hypothesis.

Exploiting hybrid vigor to enhance survival and growth for whiteleg shrimp (Litopenaeus vannamei): A complete diallel cross experiment

Whiteleg shrimp (Litopenaeus vannamei) is an economically important cultured species that is extensively cultured in China. However, there is the potential for further optimization of its survival and growth traits that are key determinants of productivity in aquaculture. This study investigated the efficacy of hybridization, a genetic improvement technology leveraging hybrid vigor, as a strategy for enhancing these traits in L. vannamei. The study was conducted using a 4 × 4 complete diallel cross experiment involving four selected strains (5, 8, 9, and 10), with the aim of identifying potential crosses exhibiting hybrid vigor. The most suitable crosses were those between strains 8 and 9, where the mid-parent heterosis (H89) was 16.52% for survival and 18.93% for growth. Our findings revealed that most reciprocal hybrids displayed higher rates of survival than their inbred parents. Additionally, an age-dependent increase in the heterosis effect on weight was observed over mid-parents and single-parents in most hybrid offspring. These findings suggest that hybridization could be a promising approach to improving the survival and growth of whiteleg shrimp. Our crossing experiment has yielded novel genetic resources for shrimp breeding, ultimately enhancing the economic importance of whiteleg shrimp.

Water quality monitoring with an early warning system for enhancing the shrimp aquaculture production

Aquaculture provided 43% of the aquatic animal food consumed by humans in 2007, and it is anticipated to expand even more to meet the increasing future demand. Marine Science Techno Park (MSTP) is one of the Techno Parks in Indonesia and is located in Teluk Awur, Jepara. MSTP has an intensive system of Vannamei shrimp farming activities. The challenge that has been faced annually is the organic matter of the remaining shrimp feed that accumulates in the waters can cause a decrease in pond water quality. Ammonia-N anions derived from the decomposition of feed residues can cause toxins in shrimp culture ponds which can further interfere with shrimp survival. The objective of this study is to design a self-controlled water quality monitoring system that is equipped with an early warning system based on internet of things (IoT) and to implement the design for analyzing the water quality including dissolved oxygen (DO), pH, and temperature in the Vannamei farming pond of MSTP UNDIP through integrating IoT which is equipped with an early warning system. If the water quality reaches a threshold value, the monitoring system will send a sound signal to the buzzer followed by sending an alert notification in real-time conditions automatically to a smartphone.

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

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

Application of land-use change model for supporting land-use planning in An Bien district, Kien Giang province, Vietnam

Forecasting land-use change is a critical step in assisting land-use planning, especially for coastal areas that are influenced by many economic and natural environmental factors. This study aims to estimate land use changes based for An Bien district, Mekong Delta based on multi-criteria assessment of factors affecting land use change. The model has been calibrated with the 2015 land-use map and verified with the 2020 map. The results of land-use change analysis in An Bien district were carried out according two scenarios: (i) forecasting the area under present conditions and (ii) forecasting land use area in the case of economic benefits and suitable environmental conditions for aquaculture production. Scenario 1 showed that the results will not change much compared to the current situation, in which rice-shrimp plays a leading role locality, however Scenario 2 showed that shrimp area will rapidly rise. In general, the simulation results allow users to explore future planning possibilities and serve as a basis for selecting appropriate land-use types.