Two independent experiments were performed to determine the effects of salinity on survival and growth of juvenile Macrobrachium rosenbergii, first one was to determine the median lethal salinity (MLS-5096h) and second one was to assess the survival and growth at different sub-lethal salinities under field condition. In MLS-5096h study 0, 5, 10, 15, 20, 25 and 30ppt salinities were used to initially find out the salinity tolerance range. Accordingly, a definitive salinity tolerance test was done in next phase to find out exact median lethal salinity by directly transferring the test species to 21, 22, 23, 24, 25, 26 and 27ppt salinity for 96h. The median lethal salinity of M. rosenbergii was estimated at 24.6ppt. In the second experiment, survival and growth performances of the prawn were recorded at different sub-lethal salinities viz., 5, 10, 15 and 20ppt along with 0ppt as control during 60 days culture period. The prawn exhibited lowest final average weight at 20ppt salinity and significantly highest at 10ppt salinity. Highest SGR and weight gain were obtained at 10 ppt followed by 5ppt, 15ppt and 0ppt salinity but differences among treatment were not significant (P>0.05). Survival rate of prawn varied between 91% (at 0ppt) and 78% (at 20ppt). The prawn grew and survived satisfactorily at 0–15ppt salinities, implying that the species can be cultured commercially at wide salinity range. M. rosenbergii can be considered as an ideal species to promote, in view of current and future climate variables as more and more coastal areas of India are going to be vulnerable to saline water inundation

Organic aquaculture is a new approach in the modern farming system. As the capital investment is higher for setting up the organic aquaculture, it is essential to conduct an economic feasibility study with compare the conventional farming system. In the current study, economic feasibility of culturing Indian major carps (IMC) using conventional culture system and organic culture system (OCS) were evaluated. IMC was cultured for three consecutive years from 2017 to 2019 in experimental ponds of 0.015 hectare (ha) area each. The crude protein content of the organic and conventional feed was maintained at the same iso-nitrogenous level (32% crude protein) but the highest production to the tune of 19 tons per ha was obtained in OCS. Further, in case of OCS, apart from fish production, vermicomposting to the tune of 45,000 kg ha⁻¹ in the first year, and 90,000 kg ha⁻¹ from second year onward is achievable by installing a vermicomposting unit of 200 tons annual capacity. Economic analysis of the culture systems assuming a project period of 10 years showed that the highest net present value (NPV) of 1.06 million USD, a payback period of one year and nine months and an internal rate of return (IRR) of 51% are achievable per ha of fish culture pond for OCS. Sensitivity analysis of various costs performed for OCS revealed that profitability of the organic fish farming investment is most sensitive to the total fish production and sale price of the organic fishes. In terms of production of fish and economics of organic culture system is proved to be the best available technique.

The aquaculture industry will be crucial in helping the world’s food supply and keep up with the demand. Aquaculture, like agriculture, must expand and develop sustainably in all the countries to keep up with the rising demand for food. To this end, the aquaculture industry has forged new scientific and technological frontiers in pursuit of long‐term food security. Among these is organic aquaculture, whose distinctive protocol has great potential to advance aquaculture. Organic aquaculture is being explored for multiple reasons, encompassing the aim to minimize environmental footprints, fulfill escalating consumer appetites for seafood, and contend within the industry this paper endeavors to address the gaps in current literature by offering an exhaustive overview of various aspects of organic aquaculture. This encompasses its regulation, production methods, food quality, environmental impact, economic viability, as well as socioeconomic and marketing aspects. It is necessary to acquire more knowledge about organic farming techniques before switching over to organic aquaculture on a large scale. Organic regulation, production, food quality, economic performance, and social and marketing issues are at the top. This review found that consumers lack understanding of organic principles, and regulations are inconsistently applied. However, organic aquaculture promotes social equality by protecting producers’ rights to work without discrimination based on gender, race, or sexual orientation factors that ultimately boost the industry’s popularity. Organic aquaculture viability varies depending on factors like feed costs, fixed expenses, and the premium pricing sensitivity, making it unfeasible for certain species. However, from both societal and economic standpoints, organic aquaculture appears most suitable for implementation in developing nations.

The growth of conventional aquaculture has created environmental issues due to excessive feeding, low dissolved oxygen level etc into the water body. Organic aquaculture is a recent development as a solution to these issues. It is a clean alternative to reduce pollution and to produce safer consumable food. In the past few decades, recirculating aquaculture systems (RAS) were introduced to maintain pond water quality through lesser water exchange, by focusing on water reuse after treatment. In this study, the technical viability of RAS was analyzed for introduction in organic aquaculture systems. Indian major carps (IMCs) were cultured through conventional methods in the three tanks of conventional system, while the same species was grown organically in another three tanks in organic system. The stocking density and physical conditions were kept same for both cultured systems. The RAS consisted of fish culture tank with an average volume of each tank was 165 m³, a screen filter, foam fractionator and trickling filter. The various water quality parameters, i.e., solid size distribution in water, and removal efficiencies in biological treatment of both systems were compared. The present study, particle size distribution of solids in water body was measured by filtration, followed by weighing of dry residue solids. Pore sizes of 1000μ, 100μ, 20μ and 3μ were employed for filtration. For organic tanks, a majority of solids are of size between 1 mm and 100 μm. The larger sized particles (> 30 μm) constitute nearly 70 % of the solids and the trait differs from the generalized conclusions of that a major part of sediments will be of sizes less than 20 μm. For the conventional tanks, majority of solids are of size between 3 mm and 20 μm and TAN shows higher removal efficiencies for effluents from organic system rather than conventional system. The results showed that organic aquaculture causes lesser pollution load per weight of fish. The particle size distribution of organic water was better compatible to screening and sedimentation than conventional water. Also the filtration efficiencies in nitrifying trickling filters of both water bodies were comparable, with that of organic water slightly on the higher side. Thus recirculating water treatment systems are introduced in organic aquaculture.