Inland Aquaculture Challenges in the Pearl River

UNCLAS SECTION 01 OF 03 GUANGZHOU 000248 SIPDIS SENSITIVE SIPDIS STATE FOR EAP/CM AND OES/PCI EPA FOR OFFICE OF INTERNATIONAL AFFAIRS E.O. 12958: N/A TAGS: EFIS SENV ECON CH SUBJECT: Inland Aquaculture Challenges in the Pearl River Delta(PRD)Region - Eutrophication and Contamination ¶1. (U) Summary: Inland aquaculture in south China faces two major environmental challenges: eutrophication (excess nutrient loading) and contamination. Guangdong officials have identified 18 lakes and reservoirs in the province as being more contaminated than Wuxi Lake, a focal point of international attention recently for excessive eutrophication. So far, existing scientific data suggest that freshwater aquaculture products in the Pearl River Delta region contain "safe" levels of certain toxic contaminants; but research has been limited and much more is needed. The potential threat of cultured invasive species is another area that needs more attention. Training and other technical assistance from U.S. and other foreign agencies and institutions could help strengthen south China's monitoring and testing systems. End summary. ¶2. (U) In China, aquaculture-derived products is big business. According to the Ministry of Agriculture - Fisheries Bureau, in 2007, China derived 68% of its total seafood output from aquaculture, ranking number one in the world for aqua-product exports. In the Pearl River Delta region, the South China Inland Fishery Zone, which includes Guangdong, Guangxi, and Fujian provinces, is China's second largest inland fishery after the middle and lower reaches of the Yangtze River. Various large and popular carp (black, big head, silver, grass, crucian, common) comprise about 90 percent of the freshwater fish species cultured in the South China Inland Fishery Zone. Other popular species include tilapia, Chinese bream, North America largemouth bass, eels, and catfish. Pond culture (as opposed to cultivation in larger open water bodies like reservoirs, lakes and river channels) is the major method of production in China's inland aquaculture and makes up about 75 percent of total production. This system relies heavily on rainfall and groundwater recharge, but often has limited drainage and recirculation and can be heavily affected by nearby sources of agricultural runoff and various industrial and municipal pollutant sources. ¶3. (U) Extremely rapid development and heavy industrialization of the PRD region has brought environmental degradation to aquaculture in South China. The two major environmental factors affecting inland (as well as marine) aquaculture in China and the PRD are eutrophication, due to excess nutrient loading; and contamination created by discharges from industry, municipal wastes, and agriculture. Other problems include the increased likelihood of bacterial and viral disease outbreaks due to the concentrated population of individual species in confined close quarters and the impact of non-native and exotic cultured aquatic species-- some of them high level predators like the North American largemouth bass-- on China's diverse and often unique indigenous fish fauna and aquatic ecosystems. Eutrophication: Aquaculture Can Foul its Own Nest -------------- -------------- ¶4. (U) Academic and government fishery and pollution monitoring experts in the Pearl River Delta area told Congen Science Fellow that excessive eutrophication is the single most damaging factor to aquatic resources, both freshwater and marine, in the PRD Region. It is likewise the major water quality problem for virtually all major rivers and coastal regions of China. According to recent media reports, Guangdong's government has identified 18 lakes and reservoirs in the province as more contaminated than even Wuxi's Lake Tai, the focus of recent international attention due to blue-green algal bloom invasions caused by extreme eutrophication. ¶5. (U) Aquaculture itself plays a major role in creating this excess of nutrients in south China because of the sheer numbers of fish farms in the PRD and coastal regions. As a result, such high concentrations of farmed aquatic animals generate tremendous quantities of excretory products as waste. The sum of all this waste - combined with excess unused fish feed and compounded by episodes of occasional water shortage, rising temperatures and poor drainage - is excess production of nutrients in the water. These in turn foster rapid and uncontrolled algal growth. Excessive algal growth can deplete oxygen, enhance the incidence of disease, GUANGZHOU 00000248 002 OF 003 stimulate the formation of more severe harmful algal blooms and cause other undesirable results. Contamination - Is There a Problem? -------------- ¶6. (U) Preliminary monitoring data, although somewhat sparse, suggest that freshwater aquaculture products in China have fewer contaminants than marine aquaculture products. About 90 per cent of the freshwater fish cultured here are varieties of fast-growing Asian carps (black, bighead, silver, grass),which take only about one or two years to reach marketable size. These species do not require a long maturation time in the ponds, nor do they occupy a high level in the food web, making them less likely than long-lived carnivorous fish (such as larger marine species) to accumulate persistent and bioaccumulative toxic (PBT) contaminants like mercury and DDT over time. According to the scientific staff of the large Guangdong aquacultur3 institute we visited, and in the view of many other aquaculture industry experts in the PRD, chemical contaminants are not considered to be a serious problem in most of the freshwater fish species which are cultured in the PRD. ¶7. (U) A leading local environmental research laboratory's 2007 Guangdong assessment of nearly 400 fish from area markets, which was reportedly the first study of its kind, found "moderate" levels of certain common contaminants such as pesticides and flame retardants in farmed freshwater fish. These were in concentrations normally ranging well below the limits enforced by the US FDA and the Chinese Government. The study, which was published internationally, concluded that consumers could safely eat more than 16 meals per month of farmed freshwater fish. China's marine fishery and aquaculture products fared more poorly, however, and tended to show higher levels than did the inland samples, with some of the cage-cultured marine fish judged safe to eat only for only about one meal per month. This information was welcome news to support the contention held by so many inside the local aquaculture field that there are few or no problems with inland aquatic contaminants. But the study only included data on a few selected persistent, traditional organic contaminants, and did not assess toxic metals like mercury. While the results of this study are encouraging for freshwater products, there appears to be growing caution among some consumers here who are gradually becoming more aware of the potential health risks from environmental contaminants in seafood. ¶8. (U) Water and aquaculture researchers in the PRD are beginning to take some additional steps to identify and monitor contamination in aquaculture products. They are also assessing ecosystem changes brought on by aquaculture here. In cooperation with the Ministry of Agriculture, the Pearl River Fisheries Research Institute of the Chinese Academy of Fishery Sciences maintains a Fishery Environmental Monitoring Center, which conducts laboratory analysis on fish samples to identify trends and background levels for various environmental contaminants, including mercury, and also to monitor and treat disease problems in the cultured fish. Threat of New Species: Largemouth Bass, a Prime Example -------------- -------------- ¶9. (U) Rapid economic development has made China's rich biodiversity especially vulnerable to invasive species and a decline of native species. The largemouth bass, a native species of Eastern North America, is swiftly becoming a very popular and high-demand product of inland aquaculture in the PRD. A high level freshwater predator species, its recent popularity in aquaculture has also allowed it to become firmly and permanently established as a "wild" invasive freshwater species in the PRD region of south China. The concept of cataloging and identifying threatened, endangered, extirpated, and invasive species of aquatic organisms is relatively new to China. Chinese scientists and aquaculture experts are aware of the potential threat of invasive fish species and are making an effort to monitor them. However, more work is needed in tracking them and assessing their impact on native aquatic organisms in the PRD region. In a step in the right direction, the Pearl River Fisheries GUANGZHOU 00000248 003 OF 003 Research Institute near Guangzhou maintains a National Fishery Environmental Field Research Station for the Pearl River Estuary, where specimens of wild fish and fish larvae from various segments of the Pearl River and upper PRD are continuously sampled and taxonomically identified. This allows fishery scientists to more effectively follow changes in fish fauna in the PRD over time, and to identify adverse trends in local fishery resources. Comment: Strengthening the Monitoring System -------------- ¶10. (U) There is still a great deficit of scientific data about the environmental impact of the Pearl River Delta's freshwater aquaculture and contamination in its output, especially about contaminants like mercury and dioxins. In addition, the government and various institutions have a tendency of not sharing the data that they do have. Further compounding the issue, a study in one area often leads to wide scale conclusions, rather than more meaningful analysis. These challenges underscore the fact that across the Chinese environmental spectrum, the government and scientific community simply lack adequate knowledge and awareness of what exactly is in the water, and what effect it is having. Even though there have been some recent but relatively minor studies, those involved in identifying and assessing risks to ecosystems and human health here - and how to minimize and correct these risks - are usually flying blind. An U.S. Assistance Role? -------------- ¶11. (U) Local scientists who have international experience and awareness of the overall situation in south China view this as a key problem. The overall lack of any large-scale monitoring efforts of aquatic species and pollutants in the ecosystems of the Pearl River Delta and the tendency not to share data between institutes and jurisdictions (reftel) limit efforts to definitively assess contaminants in inland aquaculture products and the impact of aquaculture on the local environment. Training and other technical assistance from U.S. and other foreign agencies and institutions could help strengthen south China's monitoring and testing systems. One area where assistance could be particularly helpful would be in developing air transport and deposition models to better characterize and identify important sources of mercury and other persistent and bioaccumulative toxic substances (PBTs),which may be reaching the PRD from other regions in China. Another useful step would be to provide more modern instrumentation and training in analytical techniques for identifying and monitoring high-risk PBT chemicals in aquatic media in PRD aquatic ecosystems. Training in both ecological and human health risk assessment techniques would also be valuable tools for enhancing the capabilities of Chinese agencies, scientists and institutes involved in aquaculture and food safety. ¶12. (U) Beijing Embassy ESTH and Coast Guard Liaison cleared this cable. Goldberg