Development and current situation of marine shrimp aquaculture in China: integrated multi-nutrient pond culture

Shrimp farming has always been the fastest growing industry in mariculture, contributing to improving farmers' income and the efficiency of aquaculture resource utilization in China. The shrimp industry has adopted a continuous improvement and innovative approach, from extensive to semi-intensive and intensive farming. Shrimp pond culture in coastal areas uses various high-density intensive culture models, such as highland, greenhouse and indoor industrial culture models. However, due to efficiency, environmental and social considerations, eco-friendly farming models known as integrated multitrophic aquaculture (IMTA) are increasingly being adopted. This happens most quickly on the northern and central coasts of China. The deployed IMTA culture models reviewed here are mixed culture of shrimp + crab, shrimp + fish, shrimp + sea cucumber, shrimp + jellyfish + clam, shrimp + crab + clam, shrimp + crab + clam + fish and ridgetail white shrimp in saline water.

These patterns are tailored to local conditions and biometrics. The right variety of organisms and maintaining the right environmentally friendly water quality are the keys to success. The environmentally friendly IMTA culture model described here makes full use of pond culture resources to increase production with minimal additional feed and labour input, while reducing effluent discharge and treatment costs. The performance of the shrimp IMTA model was compared with the economics of the shrimp monoculture model. An equally important outcome of the publication is the general understanding of the findings in China's vast scientific literature on shrimp farming, which has not yet been available in English.

introduce

Pond culture is a very old and traditional form of aquaculture in China and dominates freshwater aquaculture in Chinese mainland (Wang et al. 2016). Since the 50s of the 20th century, it has been used in coastal areas for the cultivation of saltwater and high-value marine life, mainly shrimp, crab and fish. In 2016, China's total marine aquaculture production reached 19.63 million tons, of which pond aquaculture production was 2.37 million tons. The crustacean farming sector began with shrimp farming in China and later developed into crab culture, with a total output of 1.56 million tonnes in 2016, accounting for 66.1% of China's total marine pond aquaculture production (MOA 2017a; FAO-IOLOS-IFFA 2018).

It was pointed out that green, low-carbon and environmentally friendly aquaculture is the concept of China's future development (Tang et al. 2016). In order to achieve this, it is necessary to explore and practice new cultural models adapted to the characteristics of different regions. With the rapid development of marine pond culture, as well as social, scientific and technological developments, China's marine pond culture model has been continuously improved and innovated to address environmental and social issues, regulations and the implementation of best management practices (Farquhar et al., 2017).

Integrated multitrophic aquaculture (IMTA) has been identified as an appropriate approach to address these issues, i.e. to limit nutrient and organic production in aquaculture through biomimetic, while being economically and environmentally sustainable, as practiced and studied around the world (Chopin et al., 2001; Neori et al. 2004; Chopin et al. 2008; Browdy et al. 2012; Samocha et al., 2015). In China, the Shrimp-based Marine Pond IMTA has been implemented in the north-central coastal areas for many years and is now regarded as the main development direction for marine pond culture due to its environmental friendliness, eco-efficiency and product safety (Tang 2017).

History and current situation of shrimp farming in China

Marine pond culture in China began with shrimp farming, and the first research on shrimp farming technology was carried out in 1952 (Wang 2015). A few years later, the preliminary results of the life cycle of the Chinese shrimp Fenneropenaeus chinensis Osbeck were first described (Liu et al. 1959). The morphological changes and discriminating characteristics of larvae from nauplii to late larvae came from systematic studies of larval development (Zhao 1965). This study, with its detailed hand-drawn morphological map of the larval stage of Chinese turtle, has become an important document for the identification of larval stage in subsequent artificial larval culture work (Wang 2015).

In 1958, after the Chinese government formulated the fishery production policy of "aquaculture first", China began large-scale shrimp pond culture (Xue 1958). Research conducted since then has developed wintering and spawning techniques for wild populations caught in the Yellow and Bohai Seas, starting with experimental-scale artificial outdoor larval rearing (Wang 2015). Before the commercial introduction of water quality control measures – mainly to adjust pH by increasing water exchange and stabilizing alkalinity by supplementing sodium bicarbonate – into larval production in 1981, it took us more than 20 years to overcome the high mortality rate of industrial-scale artificial indoor larval rearing, which is the basis of any large-scale shrimp culture (Zhang 2012), with a production density of more than 200,000 larvae m-3 (Wang 2015).

Since 1979, the former National Fisheries Service has promoted the application of shrimp hatchery technology for large-scale larval production for stocking commercial ponds. After 1982, industrial-scale artificial larval culture of new shrimp species was established, mainly Penaeus green shrimp (Alcock 1905), P. Meggie's shrimp (de Man 1888), P. chinensis (Spence Bate 1888), Penaeus monodon (Fabricius 1798) and Penaeus mildulis (de Haan 1844) (Wang 2015). Since then, shrimp culture has gradually expanded to coastal areas of China, becoming an important part of mariculture in China (accounting for 53.6% of total marine pond aquaculture production in 2016) and a rapidly growing part of mariculture in China, with a wide geographical aquaculture range, 259845 ha in 2016, accounting for 61.0% of the total area of marine pond aquaculture (MOA 2017a).

The industry plays an important social role in increasing farmers' incomes and food production efficiency in aquaculture (MOA 2017a) (Figure 1). From south to north, shrimp farming takes place in all coastal provinces of China (Figure 2). The highest annual production (2016) was 462875 tonnes, located in Guangdong, followed by Guangxi (255444 tonnes), Shandong (123582 tonnes), Fujian (117487 tonnes) and Hainan (113,910 tonnes), Jiangsu (78,913 tonnes), and four other provinces all produced less than 60,000 tonnes of shrimp (MOA 2017a).

P. chinensis (Boone 1931), Penaeus monodon, P. japonicas, P. chinensis chinensis and Exopalemon carinicauda Holthuis (1950) are the main species in commercial farming in China today. Each species grows in areas where conditions match their respective biological needs (Table 1). Among these species, Pacific white shrimp (Zhang 1990), introduced to China in 1988, had the highest production in 2016 at 932297 tonnes, accounting for 73.3% of total shrimp culture, followed by tiger shrimp (71,163 tonnes), black horse shrimp (55,885 tonnes) and Chinese shrimp (39,288 tonnes) (MOA 2017a).

Over the past 20 years, China's rapid economic development has led to a significant and sustained increase in domestic demand for shrimp, with consumers preferring live shrimp. As a result, the proportion of shrimp exported has been declining as production has increased, from 38.1% of total production of 217994 tonnes in 2000 (Sun & Che 2003) to 13.2% of total production of 1271743 tonnes in 2016 (MOA 2017a; MOA 2017b）。 As a result, nearly 90% of China's domestic shrimp products have been and are expected to continue to be consumed domestically.

Development and current state of seawater shrimp farming, with an emphasis on integrated multi-trophic pond aquaculture farms, in China – a review