Changes in mariculture and offshore seawater quality in China during the past 20 years

Abstract

Mariculture can provide a large amount of food without occupying land resources, which provides important assistance for humans to achieve sustainable development. In this paper, China, where the output of mariculture exceeds half of the global output, is taken as the research area. Based on the spatial distribution data of three periods of mariculture along the coast of the Chinese Mainland in 2000, 2010, and 2020 obtained from remote sensing images and from the perspective of the mariculture center, the spatial development of mariculture in three periods in China is explored. Furthermore, by spatially overlaying mariculture data with concurrent water quality data, the relationship between the development and changes in the mariculture center and the seawater quality in different geographical environments was analyzed at the national scale.. We found that (1) Mariculture in China exhibits a noticeable geographical differentiation, with the scale and development speed of mariculture in northern regions surpassing that of the southern regions. (2) Good seawater quality is the prerequisite for the formation of mariculture centers, while water quality deterioration is detrimental to the development of mariculture. (3) The formation of large-scale high-density mariculture centers does not necessarily lead to deterioration of the seawater quality. Furthermore, we found that the water depth is an important factor leading to the spatial distribution pattern of mariculture in China, i.e., dense in the north and sparse in the south. The flow velocity is an important factor determining the water quality changes in mariculture centers.