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Fishery-dependent communities are highly susceptible to the impacts of climate change due to their proximity to vulnerable coastal areas and reliance on ecosystem services for their livelihoods. The study assessed the effects of climate change on the socioeconomic livelihoods and adaptive capacity of Xuan Tu, a community located in South Central Vietnam. The assessment employed the social vulnerability index (SVI) and adaptive capacity index (ACI). A hybrid data collection approach was utilized to gather information from households, and a composite method was employed to aggregate the data, enabling an assessment of community vulnerability. The findings indicated exposure, sensitivity, and adaptive capacity index values of 0.16, 0.34, and 0.26, respectively. The community exhibited a moderate vulnerability to climate change, with a social vulnerability index of 0.43. Notably, economic sufficiency, access to social groups, and level of education emerged as significant factors in reducing social vulnerability. To adapt to climate change, the community modified their fish feeding practices, fish culture methods, increased technology usage, and diversified their sources of income. However, the study identified a lack of institutional support as a significant obstacle to the community's autonomous adaptation. Based on these results, the study recommends livelihood diversification and the implementation of planned adaptation strategies to enhance preparedness for climate emergencies in South Central Vietnam.

The use of hydroponics to cultivate economic crops is an emerging agricultural practice in Nigeria. There is, however, a paucity of information on the economic viability and valuation of the production systems. This study investigated hydroponics' profitability and economic viability under small- and medium-scale production systems. The economic viability of ten hydroponic farms were evaluated using the financial metrics: net present value (NPV), internal rate of return (IRR), benefit-cost ratio (BCR), and sensitivity analysis. Sensitivity analysis based on positive and negative changes in the running cost and gross annual revenue was adopted to measure the robustness of the production method. The positive NPVs of the small-scale farmer (€42,895) and medium-scale farmer (€331,465) at a 15% discount rate show that both production scales are economically viable. The ten-year IRR of both production scales was about 83%. Similarly, the BCR showed that both the small-scale farmers (5.07) and the medium-scale farmers (4.91) are significantly profitable. In the sensitivity analysis, the small-scale farmers were more sensitive to recurrent 5% changes in the running cost at the 13% threshold. On the other hand, medium-scale farmers were less sensitive with a threshold value of 58.4%. Similarly, small-scale farmers are more sensitive to a 15% reduction in the gross annual revenue, with a negative net return of -€956. It is imperative to state that, though starting an investment in hydroponics requires a high initial investment, medium-scale farmers would be less sensitive to changes in the running cost of production in the face of uncertainties.

Aquaponics is a food production system that combines aquaculture with hydroponics. The simultaneous existence of fish, beneficial bacteria and plants in the same water loop predisposes the fish and bacteria to a possible detrimental effect of plant protection products. Additionally, there is an inadequate exploration of scientific studies on the impact of pesticides on fish and bacteria in aquaponics systems. This study investigated the effects of three commercial insecticides based on the following active ingredients: pyrethrum, azadirachtin, and spinosad, on aquaponics systems. Due to ethical concerns in animal testing, applying insecticides directly to aquaponics setup was impossible. Therefore, three separate experiments were conducted: (1) Pesticide runoff rate – in which insecticides were applied to basil (Ocimum basilicum) plants grown in two hydroponic systems: media bed and floating raft. The concentrations of applied insecticides were measured in the water of nutrient solutions of the hydroponics after 1, 3, 6, 12, 24, 36, 48, 72 and 96h to establish a pattern of degradation of insecticides. The result from this experiment showed that pyrethrum and spinosad were detected in unquantifiable concentrations in the nutrient solutions. Hence, further experiments were conducted only with azadirachtin. In a biofilter trial (2) – azadirachtin, at three concentrations (1.5 µg L-1; 7.5 µg L-1; and 15 µg L-1), was added to a running biofilter to investigate the effects on nitrifying bacteria. Mild effects were recorded in the nitrification and bacteria microbiome. In the third trial (3) – Nile tilapia (Oreochromis niloticus) were exposed to similar concentrations of azadirachtin for seven days (and the same period for recovery) to investigate effects on fish hematology, blood biochemistry, antioxidative enzymes in the brain, gills, muscle, liver and intestine and histopathology of gills and liver. Results showed mild effects in hematology and biochemistry profile in fish and higher levels of lipid peroxidation in the liver during the exposure. The results indicate a safe use of pyrethrum and spinosad in aquaponics setup, while azadirachtin has to be used with care, especially in coupled aquaponics systems.

Aquaponics has the potential to produce sustainable and accessible quality food through the integration of hydroponics and aquaculture. Plants take up dissolved nutrients in fish wastewater, allowing water reuse for fish. However, the simultaneous presence of fish and plants in the same water loop has made phytosanitary treatments of diseases such as powdery mildew problematic due to risks of toxicity for fish and beneficial bacteria, limiting its commercialization. Entomopathogenic and mycoparasitic fungi have been identified as safe biological control agents for a broad range of pests. This study aimed to investigate the efficacy of entomopathogenic fungi, Lecanicillium attenuatum (LLA), Isaria fumosorosea (IFR), and mycoparasitic fungus Trichoderma virens (TVI) against Podosphaera xanthii. Also, we investigated the possible harmful effects of the three fungal biocontrol agents in aquaponics by inoculating them in aquaponics water and monitoring their survival and growth. The findings showed that the three biocontrol agents significantly suppressed the powdery mildew at 107 CFU/ml concentration. Under greenhouse conditions (65-73% relative humidity (RH)), a significant disease reduction percentage of 85% was recorded in L. attenuatum-pretreated leaves. IFR-treated leaves had the least AUDPC (area under disease progress curve) of ~434.2 and disease severity of 32% under 65-73% RH. In addition, L. attenuatum spores were the most persistent on the leaves, the spores population increased to 9.54 × 103 CFUmm-2 from the initial 7.3 CFUmm-2 under 65-73%. In contrast, in hydroponics water, the LLA, IFR, and TVI spores significantly reduced by more than 99% after 96 hrs. Initial spore concentrations of LLA of 107 CFU/ml spores were reduced to 4 x 103 CFU after 96 hrs. Though the results from this study were intended for aquaponics systems, relevance of the results to other cultivation systems are discussed.