Environmental effects of mariculture in China: An overall study of nitrogen and phosphorus loads

Abstract

Eutrophication in coastal area has become more and more serious and mariculture potential is a main cause. Although there are some quantitative research on nutrient loads in national and global perspective, the calculation method problems make the results controversial. In this paper, the farming activities are divided into fed culture types (include cage culture and pond culture) and extractive culture types (e.g. seaweed, filter-feeding shellfish culture). Based on the annual yield of China in 2019 and feed coefficient of fed culture types and carbon (C), nitrogen (N), and phosphorus (P) content of extractive culture types, the annual nutrient loads was estimated. The results showed that to coastal region of China (1) annual nutrient released by fed culture types were about 58 451 t of N, 9 081 t of P, and annual nutrient removed by harvest of extractive culture types were 109 245 t of N, 11 980 t of P and 1.86×10 6 t of C. Overall, the net amount of nutrient removed annually by mariculture industry were 50 794 t of N and 2 901 t of P. (2) The nutrient released from mariculture industry influenced nutrient stoichiometry. Pond farming and seaweed farming had the potential of increasing the molar concentration ratio of N and P (N:P), while cage farming and bivalve farming decreased the N:P. (3) Due to different mariculture types and layouts in the coastal regions in China, N and P loading were regional different. Among the coastal regions in China, net release of nutrient from mariculture occurred only in Hainan and Guangxi regions, while in the other regions, N and P were completely removed by harvest. We suggest decrease the amount of fed culture types and increase the amount of integrated culture with extractive culture types. This study will help to adjust mariculture structure and layout at the national level to reduce the environmental impact.

Identification and Characterization of Infectious Pathogens Associated with Mass Mortalities of Pacific Oyster (Crassostrea gigas) Cultured in Northern China

“…Because of its rapid growth potential and wide adaptability to environmental conditions, the Pacific oyster has been introduced to many parts of the world as a supplemental aquaculture species for a decline of the local native oyster species [ 2 ]. In China, the Pacific oyster aquaculture production has increased from 0.81 million tonnes in 2000 to 1.46 million tonnes in 2018, with a growth rate of 3.32% per annum [ 3 ]. Beyond China, the Pacific oyster aquaculture production has been nearly stagnant from the mid-1980s [ 4 ], which fluctuates around 0.7 million tonnes, or even dropped to less than 0.6 million tonnes for several years [ 5 ].…”

“…Beyond China, the Pacific oyster aquaculture production has been nearly stagnant from the mid-1980s [ 4 ], which fluctuates around 0.7 million tonnes, or even dropped to less than 0.6 million tonnes for several years [ 5 ]. China is responsible for most of the increased production of Pacific oyster aquaculture in recent decades [ 3 , 4 ]. The rapid increase in China could be attributed to a suite of technological advancements, such as artificial seeding in hatcheries, and longline aquaculture in the open sea [ 6 ].…”

The Probiotic Bacillus hwajinpoensis Colonizes the Digestive System of Crassostrea gigas Larvae and Protects Them from Vibrio alginolyticus Infection

“…The production of Pacific oysters has increased rapidly in recent years in China, and reached 1.46 million tons in 2018 [3]. The Pacific oyster aquaculture relied on diploid seeds before 2016 in China, which were primarily collected from local waters where oyster aquaculture is practiced [4]. In recent years, the triploid oysters were successfully developed in China, and widely embraced by farmers [4].…”

“…The Pacific oyster aquaculture relied on diploid seeds before 2016 in China, which were primarily collected from local waters where oyster aquaculture is practiced [4]. In recent years, the triploid oysters were successfully developed in China, and widely embraced by farmers [4]. It is estimated that the production of triploid oysters has accounted for over 70 percent of the production in China [5].…”

“…To meet the huge demands for triploid oyster seeds, the bivalve hatcheries have expanded rapidly, which has brought new threats to the industry [6]. This is due to, as all researchers and practitioners have noted, more frequent occurrences of production failure of oyster seeds [4]. Mass hatchery crashes have caused shortages in seed oysters for commercial shellfish producers.…”