Industrialized aquaculture is an essential trend for aquaculture development in China, owing to its considerable advantages in lower water consumption, higher productivity and sustainability. Here is a review of the current status and solutions for the development of industrialized aquaculture in China.
China is the world’s largest aquaculture producer: In 2020, it produced 49.90 million tons of aquaculture fish, accounting for 57.03% of the global total (FAO, 2022). However, the development of Chinese aquaculture has been confronted with many problems due to excessive use of traditional culture systems (e.g., ponds and cages), such as disease outbreaks, environmental pollution, and food safety concerns.
These problems have seriously restrict sustainable development of the Chinese aquaculture industry. There is an urgent need to improve this situation by developing culture systems in which fish production can be highly controllable and environmentally friendly, such as industrialized aquaculture.
Industrialized aquaculture is an important future trend for aquaculture development in China, owing to its advantages in saving water and land resources and promoting higher productivity and sustainability. However, little information on its current status has been available up until now.
Here is a review of the current status of industrialized aquaculture in China, the main issues in its development, as well as possible solutions for its future direction.
Definition of industrialized aquaculture in China
According to government statistics, industrialized aquaculture systems can be defined as a circulating filter types, warm drainage types, ordinary flow types, and warm water types (FBMA, 2021). Compared with traditional culture methods (e.g., ponds and cages), industrialized aquaculture systems have the following advantages:
✓ They have more controllable conditions, a higher culture density, and more extended production periods.
✓ They save land and water resources: compared with conventional aquaculture systems, some industrialized aquaculture systems (e.g., recirculating aquaculture systems) use 90–99% less water and less than 1% of the land area.
✓ Their construction sites are more flexible. Conventional aquaculture systems need to be built close to the water source and are generally far from the aquatic products markets.
✓ They improve feed utilization and reduce pollutant emissions.
Industrialized aquaculture models in China
At present, industrialized aquaculture models in China can be divided into three categories: flowing water systems, recirculating aquaculture systems (RAS), and aquaponics systems (Figure 1). Flowing water systems use underground water as the primary water source.
After culture, the wastewater, enriched with nitrogen and phosphorus, is discharged directly (Figure 1) (Cang, 2019; Shen et al., 2014).
Despite a higher production rate and a shorter culture period, this model has some drawbacks. These systems ignore ecological and environmental protection measures and use many resources (e.g., water, land, and electricity) with low efficiency; additionally, they overlook long-term interests, intensify intra-industry competition, and make it difficult to standardize the management and development of aquaculture (Cang et al., 2018).
RAS is becoming more popular in China, especially in Shandong, Tianjin, and Liaoning provinces. However, the proportion represented by this model in industrialized aquaculture is still low. Taking the coastal provinces of Liaoning, Hebei, Tianjin, and Shandong provinces as examples, the area occupied by RAS accounts for only 6.72% of the total area of industrialized aquaculture (Wang et al., 2013).
The biological treatment (microbial nitrification and denitrification) of RAS produces the greenhouse gas N2O, whose effect is more than 310 times greater than CO2 in inducing global warming (Hu et al., 2012). To reduce the potential impact of such compounds in the environment and fish health, aquaponic systems were developed.
Aquaponics is a combination of aquaculture and hydroponics (Figure 1) that uses vegetables in hydroponics systems to absorb waste (e.g., CO2, NO3, and PO43- ) from the rearing water and produce O2. These systems achieve the double purpose of producing farmed fish and hydroponic vegetables.
Current status of industrialized aquaculture in China
According to government statistics, records on industrialized aquaculture production in China can be traced back to 2003 (FBMA, 2022). At that time, the production from industrialized aquaculture accounted for 0.4% of total aquaculture production. After an 18-year effort, the production and farming areas achieved great progress.
In 2021, the total production and total farming water volume of industrialized aquaculture were 6.8×105 tons and 9.6× 107 m3, respectively (Figure 2).
The farming area is occupied by industrialized aquaculture increased from 3.3× 107 m3 in 2003 to 9.6×107 m3 in 2021, with an annual growth rate of 6.2%. During that period, the freshwater industrialized aquaculture area increased from 2.4× 107 m3 to 5.5× 107 m3 and the seawater industrialized aquaculture area increased from 9.2× 106 m3 to 4.1× 107
m3 (Figure 2).
From 2003 to 2021, industrialized aquaculture production in China increased from 1.2× 105 tons to 6.8×105 tons, with an annual growth rate of 10.2%. During the same period, industrialized freshwater aquaculture production increased from 8.2×104 tons to 3.2×105 tons and industrialized seawater aquaculture production increased from 3.7×104 tons to 3.6×105 tons (Figure 2).
Shandong and Fujian provinces rank high above others in industrialized aquaculture production and farming areas. In 2021, these provinces occupied 57.1% of the total industrialized aquaculture production and 54.4% of the total industrialized aquaculture area (Figure 3).
Fujian, Shandong, Hubei, Jiangxi, and Anhui are the main provinces of industrialized freshwater aquaculture, together accounting for 73.6% and 60.5%, respectively, of the total industrialized freshwater aquaculture production and areas in 2021.
Shandong, Liaoning, Fujian, Jiangsu, and Hainan are the main provinces of industrialized seawater aquaculture in China, together accounting for 88.9% and 79.2%, respectively, of the total industrialized seawater aquaculture production and area in 2021.
Existing problems and possible solutions for industrialized aquaculture in China Current industrialized aquaculture in China has made important breakthroughs in aquaculture theory and technology, however, there are still many problems that limit the sustainable development of industrialized aquaculture.
“Firstly, high capital and operational costs limit the broad application of industrialized aquaculture in China. Engle et al. (2020) examined the cost structures of RAS for Atlantic salmon, trout and tilapia and found that capital costs were the greatest cost for RAS, representing 23–57% of the total costs.”
In addition, high energy consumption is the main factor contributing to the elevated operational costs of industrialized aquaculture. The use of renewable energy sources (such as geothermal and solar energy) can reduce the operational costs of industrialized aquaculture.
Biofloc technology (BFT), a technique for enhancing water quality and producing proteinaceous feed into aquaculture through balancing carbon and nitrogen in the system, has been proven helpful in supplying feed for aquatic animals.
Secondly, the selling price of farmed species in industrialized aquaculture does not have a comparative advantage over other culture systems.
The fish market price is a crucial factor in determining the profitability of industrialized aquaculture. With the improvement of living standards, people are paying more attention to health and are willing to pay extra for pollution-free and environmentally friendly agricultural products.
Compared with traditional culture models, industrialized aquaculture has a considerable advantage in controlling fish production and producing pollution-free aquatic products. Thus, increasing pollution-free certification and enhancing the advantages of green brands of industrialized aquaculture products could improve their market competitiveness.
Thirdly, industrialized aquaculture technology is still at an early stage, and regional development is uneven. In order to decrease the detrimental effects of flowing water systems on the environment, sufficient funding is needed to promote the transformation of culture models from flowing water aquaculture to closed recirculating aquaculture and quaponics.
Additionally, coastal regions should fully exploit their technological advantages, invest the necessary elements in industrialized aquaculture, and continuously optimize their production systems. Inland regions should fully utilize their resource advantages and improve their industrialized aquaculture technology.
“Fourthly, there remains a lack of suitably experienced RAS managers and operators. Industrialized aquaculture emphasizes multi-professional work and needs more specialized and competent people in its workforce.”
Poor management due to a lack of professionals in water quality control, water chemistry, and waste management is a major factor leading to the failure of RAS operations. Therefore, it is necessary to train people in the responsibility of managing industrialized aquaculture systems.
Finally, the development of industrialized aquaculture has been adversely affected by the coronavirus disease 2019 (COVID-19) pandemic. The COVID-19 pandemic and the measures being taken to contain the epidemic, have made a negative impact on the aquaculture sector (including industrialized aquaculture) in China.
A series of strategies have been recommended to deal with these problems, such as the support of free legal advice and financial assistance to companies and farmers along the aquaculture industrial chain.
Industrialized aquaculture is an environmentally friendly and sustainable culture model, possessing considerable advantages over traditional culture systems in saving water and resources, increasing production and food security of aquatic products, and reducing pollutant emissions.
At present, industrialized aquaculture is still at an early stage of development and is mainly distributed in coastal regions.
The development of industrialized aquaculture is restricted by high capital and operational costs, the uncompetitive market price of fish, the uneven distribution of industrialized aquaculture, a lack of suitably experienced RAS managers and operators, and the COVID-19 pandemic.
Possible solutions to these problems include technological innovations in systems optimization, the use of renewable energy sources and biofloc technology, the pollution-free certification of industrialized aquaculture products, more trained professionals in water quality control and waste management, and financial assistance to companies and farmers along the aquaculture industrial chain.
This is a summarized version developed by the editorial team of Aquaculture Magazine based on the review article titled “CURRENT STATUS OF INDUSTRIALIZED AQUACULTURE IN CHINA: A REVIEW” developed by: Chen, W. and Gao, S. – Henan University of Science and Technology, Luoyang China.
The original article, including tables and figures, was published on FEBRUARY 2023, through ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH.
The full version can be accessed online through this link: https://doi.org/10.1007/s11356-023-25601-9