The trends of aquacultural nitrogen budget and its environmental implications in China

Luo, Zhibo; Hu, Shanying; Chen, Dingjiang

doi:10.1038/s41598-018-29214-y

Cited by 55 publications

(15 citation statements)

References 45 publications

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“…The rapid development of China's economy has been accompanied by an increasing demand for food sources near urban areas. To meet this challenge, China has become the world's largest producer and consumer of aquaculture products [1,2]. Intensive aquaculture is an important strategy for addressing the dual shortages of farm and water resources.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics of an in-pond raceway system with an aeration plug-flow device for application in aquaculture: an experimental study

Cheng

Xie

et al. 2019

R. Soc. open sci.

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An in-pond raceway system (IPRS) is an effective intensive aquaculture practice for regions with high water consumption and limited land resources. Water flow and dissolved oxygen (DO) are important for sustainable aquaculture. Several innovations have been made in IPRS design and operation to increase water exchange and DO concentration; one of these is the aeration plug-flow device (APFD). The APFD is commonly used in China as the only power source for water recirculation in aquaculture ponds. Understanding of the hydrodynamics of the system is necessary to improve the design of the IPRS with APFD. To this end, we performed experimental studies on a model system. We measured three-dimensional velocity at various locations using an Acoustic Doppler Velocimeter. Velocity distribution and turbulence characteristics were assessed, and plug-flow characteristics were analysed. Two patterns of velocity and turbulence in horizontal sections were observed: near the APFD, the water flow was intensively pushed downstream and simultaneously recirculated; farther away, the reflux area gradually decreased and the velocity and turbulence distribution trended towards uniform. Secondary flows occurred in different directions, which improved the diffusion of materials and DO retention. The system is effectively self-circulating, and the plug-flow capability may be scaled up for commercial application.

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Section: Introductionmentioning

confidence: 99%

Hydrodynamics of an in-pond raceway system with an aeration plug-flow device for application in aquaculture: an experimental study

Cheng

Xie

et al. 2019

R. Soc. open sci.

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“…These data imply that the FCR is very low, which is an indication that the natural food contributes to the fish growth. If we compare the N input (1.1 tg.N.yr -1 ) and output (1.33 tg.N.yr -1 ) in Chinese aquaculture, which contributes 80% of global yield, more N was harvested in fish than applied with the feed N (Luo et al, 2018). This indicates that pond based fed aquaculture is very efficient in terms of nutrient input and output.…”

Section: Approaches For a Sustainable Growth Of Aquaculturementioning

confidence: 99%

Feeding fish or pond . . .?

Kabir¹

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Globally pond aquaculture is the predominant fish/shrimp farming system. Roughly 70% of the farmed fish and shrimps are produced in semi-intensive ponds where feed is a major nutrient supplier but where also natural food contributes to the productivity. Current knowledge on fish nutrition is based on studies where natural food is absent or available at a minimum level. When a complete feed, formulated on the basis of the above nutritional studies, is applied as supplementary feed in a pond where also natural food is available, much of the nutrients are not retained in the fish and the efficiency goes down. The aim of this research was to generate knowledge on how dietary macro-nutrients (with a focus on dietary carbohydrates) determine fish growth directly and indirectly (via natural food) in ponds. In a pond, the carbon to nitrogen (C:N) ratio in the system determines the productivity of natural food. The hypothesis underlying the current PhD research was that lowering the scarce and expensive macronutrients (e.g. protein and fat) in the feed would be compensated by an increased contribution of natural food as a result of a higher C:N input into the system, and thus not leading to lower fish yields. We conducted four experiments to test this hypothesis and have observed that lowering the dietary protein to energy ratio in the feed increased fish production at the pond level, mainly because of an indirect effect of the diet by enhancing the natural food in the pond. The type of non-protein dietary energy (lipid or carbohydrate) did not affect fish performance, not directly as feed nor indirectly via influencing the natural food web of the pond. However, the type of dietary non-starch polysaccharides (NSP) influenced natural food production and ultimately fish growth. Fish performance was better with slowly degradable NSPs in the feed. In all our studies we have noticed that feeding level increased fish production but also increased FCR. We have also observed that fish production increased with increasing stocking density (within the tested levels). Culture intensity (feeding level and stocking density) did not interact with the influence of the dietary macro-nutrient composition (i.e. P:E ratio) on pond productivity which means that enhancement of the natural food web through diets is possible even with increasing culture intensity. So, in ponds with a functional natural food web, the optimal macronutrient composition of supplementary feeds for tilapia differs from the optimal composition as recommended by NRC (1993, 2011) for tilapia. This may be related to the fact that the NRC recommendations were developed without the presence of natural food, and that the effect of the latter may be related to a possible enhancement of its production due to the extra nutrient input in the ecosystem via the waste of the fish (fertilizing effect). However, when monitoring the food web in the ponds, we have barely noticed differences among the treatments. This calls for improved methods to quantify the contribution of natural f...

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“…bloomed in the Gulf of Thailand due to the disposal of untreated sewage. Luo, et al [72] indicated that the continuous accumulation of certain compounds, e.g., nitrogen, can lead to acidification and cause adverse effects on aquatic plants and animals, with significant biotic damage.…”

Section: Water Pollutionmentioning

confidence: 99%

Aquaculture Production and Its Environmental Sustainability in Thailand: Challenges and Potential Solutions

Sampantamit

Lachat

et al. 2020

Sustainability

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Though aquaculture plays an important role in providing foods and healthy diets, there are concerns regarding the environmental sustainability of prevailing practices. This study examines the trends and changes in fisheries originating from aquaculture production in Thailand and provides insights into such production’s environmental impacts and sustainability. Together with an extensive literature review, we investigated a time series of Thai aquaculture production data from 1995 to 2015. Overall, Thai aquaculture production has significantly increased during the last few decades and significantly contributed to socio-economic development. Estimates of total aquaculture production in Thailand have gradually grown from around 0.6 to 0.9 million tons over the last twenty years. Farmed shrimp is the main animal aquatic product, accounting for an estimated 40% of total yields of aquaculture production, closely followed by fish (38%) and mollusk (22%). Estimates over the past decades indicate that around 199470 ha of land is used for aquaculture farming. Out of the total area, 61% is used for freshwater farms, and 39% is used for coastal farms. However, this industry has contributed to environmental degradation, such as habitat destruction, water pollution, and ecological effects. Effective management strategies are urgently needed to minimize the environmental impacts of aquaculture and to ensure it maximally contributes to planetary health. Innovative and practical solutions that rely on diverse technology inputs and smart market-based management approaches that are designed for environmentally friendly aquaculture farming can be the basis for viable long-term solutions for the future.

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The trends of aquacultural nitrogen budget and its environmental implications in China

Cited by 55 publications

References 45 publications

Hydrodynamics of an in-pond raceway system with an aeration plug-flow device for application in aquaculture: an experimental study

Hydrodynamics of an in-pond raceway system with an aeration plug-flow device for application in aquaculture: an experimental study

Feeding fish or pond . . .?

Aquaculture Production and Its Environmental Sustainability in Thailand: Challenges and Potential Solutions

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