The fast increase in aquaculture is exacerbating problems of environmental pollution. To reduce the production of waste in aquaculture, recent research in China has focused on species selection, diet formulation and feeding management. Energy budgets are used to evaluate a potential aquaculture species. The improvement of diet formulation includes balancing nutrients, reducing N and P contents, and reducing the use of trash fish and the use of supplements. The digestibility of different feed ingredients has been determined in some species, for a balanced diet formulation. The potential contribution to the reduction of N and P loadings in waste water of increasing palatability and digestibility, selecting suitable protein sources, and using lipid, carbohydrate, and enzymes has been demonstrated. Bio-energetic modelling has been used to predict the growth and nutrient requirements, to decrease feed input and to lower the waste production. It has been shown that in some fish, compensatory growth increases feed utilisation and decreases N loading. Polyculture increases the utilisation of fish feed and decreases nutrient loading of waste.
Mango is an important tropical fruit, and thrips are important pests that have threatened mango yield and quality in recent years. It is important to determine the dominant species and distribution of thrips in mango for effective thrips control. In the present study, the species of thrips in mango flowers in the five main mango-producing provinces of China, and the species of thrips in different phenological stages of mango in Hainan Province were investigated. Thrips species on weeds in mango agroecosystems were also determined. The results indicated that in total there are 41 species of thrips in mango orchards in the five main mango-producing provinces of China, belonging to 21 genera, five subfamilies and three families. These are 31 species in 13 genera of Thripidae, nine species in seven genera of Phlaeothripidae, and one species in one genus of Aeolothripidae. The major species of thrips differed across the main mango production areas. Thus, 26, 17, 23, 12 and 7 species of thrips were collected in mango orchards in Hainan, Guangxi, Yunnan, Sichuan and Fujian, respectively. Frankliniella occidentalis (Pergande), an important invasive pest in China, was only discovered in mango orchards in Yunnan and Sichuan. Thrips species and population dynamics are closely related to the phenological stage of mango. In Hainan, the dominant thrips species during the shoot period and young fruit stage was Scirtothrips dorsalis Hood. In the flowering period, the thrips population increased significantly and species composition became complicated in the field, with Thrips hawaiiensis and F. intonsa being the dominant species. Frankliniella intonsa and T. hawaiiensis were the dominant species on weeds in the mango ecosystem, which was consistent with them being dominant thrips species on mango. It is speculated that in mango ecosystems, weeds provide refuge to thrips and removing weeds benefits thrips control in mango orchards during the flowering period.