Mariculture-Related Environmental Concerns in the People's Republic of China

The People’s Republic of China (China) is the world’s largest producer of aquacultured products. In 2002, the total production of fisheries was 42.6 million tons; of that, 12.46 million tons was from mariculture. On the one hand, mariculture has produced plenty of food and especially additional protein for the Chinese people; on the other hand, the high level of mariculture activity has brought about many environmental issues. One of the largest impacts of mariculture on the ocean environment is self-pollution produced by the farming activities. Effluents, excess feeds, and excretions of organisms in hatchery culture, shrimp in pond culture, mollusks in raft culture, and fishes in cage culture are the major pollution sources. Excess phosphorous and nitrogen compounds from these sources have generated serious eutrophication and may even trigger red tide. The deteriorated aquatic environment has contributed to the spread of different diseases in aquacultural animals, which causes and greatly aggravates loss of production. Biodiversity changes due to mariculture activities are also an environmental concern. Losses in the genetic diversity of cultured shrimps and scallops have been found through biochemical analyses. Inbreeding and limited numbers of parental organisms may be the main causes. Adequate representation of germplasm diversity and high-quality offspring and seedlings should be the focus of greater attention in Chinese mariculture. Also, although the introduction of exotic species is an effective approach to promote the development of mariculture, it can be accompanied by some risk of genetic contamination. The introduction of the bay scallop from the USA is an example of a successful introduction of a species for aquaculture without apparent genetic risk to native species. To maintain sustainable development of Chinese mariculture, the author suggests several avenues of action that should be implemented in China to effectively and rapidly reduce the environmental pollution caused by mariculture.