Experts warn that mariculture is becoming an important pollution source in coastal waters, so it is necessary to regulate mariculture activities through laws and implement supervision and monitoring to ensure marine production.
Experts warn that mariculture is becoming an important source of pollution in coastal waters, and it is necessary to standardize mariculture activities according to law and implement supervision and monitoring to ensure the sustainable development of marine industry.
Xinhua News Agency, Beihai Electric (Reporter Liang Siqi, Ma Shun) As the economic growth point of marine industry, mariculture has brought huge economic benefits, but also caused a series of environmental problems. Recently, at the national coastal waters environmental monitoring conference held in Beihai, Guangxi, experts warned that mariculture is becoming an important pollution source in coastal waters, and mariculture activities must be regulated and monitored by law to ensure the sustainable development of marine industry.
According to the information provided by the meeting, the offshore area of China is about 370,000 square kilometers. In recent years, with the rapid development of coastal economy and the increasing development and utilization of marine resources, the degree of pollution is increasing day by day. The water quality above Grade III accounts for about 56.8% of the coastal area, and the water quality above Grade I only accounts for 14.7%. The occurrence of red tide increased from 1-2 times a year in 1970s to more than 20 times a year in 1990s.
From the composition analysis of seawater pollution, the main pollution factors in China's coastal waters are inorganic nitrogen and active phosphate, which are caused by the inflow of domestic sewage from overseas rivers and cities, as well as the mariculture of fish, shrimp and shellfish. Taking shrimp culture as an example, experts say that even in the best managed shrimp farm, 30% of the bait has not been eaten, and the nitrogen and phosphorus nutrients dissolved in the residual bait are the main pollution sources in the shrimp pond and its nearby shallow sea. Qin Qiurong, head of the research group of "Coastal Eutrophication Research and Red Tide Investigation" in Beihai Marine Environmental Monitoring Center Station, pointed out that the self-pollution of mariculture provided a suitable ecological environment for red tide organisms, accelerated their reproduction and induced red tides.
Due to the lack of planning, the "mariculture fever" has caused direct damage to the ecosystem. Mangroves, along with coastal marshes, coral reefs and upwelling, are called "four marine ecosystems with the richest biodiversity", which have the functions of preventing soil erosion, purifying seawater and preventing viruses. In recent years, the phenomenon of artificial felling of mangroves for beach culture has occurred from time to time. 1From June 1999 to April 2000, more than 30 hectares of mangroves were reclaimed in Zhakou Town, Beihai City, and dozens of hectares were cut down in other coastal areas of Beihai City. The first phase of the Maoweihai reclamation project in Qinzhou Bay reached 760 hectares, and no consideration was given to protecting more than 200 hectares of mangroves in the dike. Experts pointed out that the 65,438 0.35 square kilometers of Maoweihai has only one narrow outlet connected with the open sea, and its water exchange capacity is low. Such a large area of reclamation and deforestation will lead to increased pollution, threatening the survival of four precious seafood in this sea area-oysters, blue crabs, prawns and groupers, which will eventually outweigh the benefits.
According to the introduction of aquaculture development in Beihai City, the shallow sea beach area within Beihai 10 m isobath is 2.98 million mu, and only 400,000 mu is currently developed, only 13.4%, and the shallow sea is hardly developed and utilized.
Dr. Fan Hangqing, a mangrove expert from Guangxi Institute of Oceanography, said: mariculture must be scientifically demonstrated and developed in disorder, only considering the benefits and ignoring the overall ecological and environmental benefits. The ecological negative effects such as biodiversity destruction and land salinization will be very serious.
Overseas Edition of People's Daily (9th Edition +0 on March 65438, 2006)