Cablegate: Inland Aquaculture Challenges in the Pearl River

DE RUEHGZ #0248/01 1210908
R 300908Z APR 08





E.O. 12958: N/A
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

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

12. (U) Beijing Embassy ESTH and Coast Guard Liaison cleared this


© Scoop Media

World Headlines


Werewolf: Gordon Campbell On North Korea, Neo-Nazism, And Milo

With a bit of luck the planet won’t be devastated by nuclear war in the next few days. US President Donald Trump will have begun to fixate on some other way to gratify his self-esteem – maybe by invading Venezuela or starting a war with Iran. More>>

Victory Declared: New Stabilisation Funding From NZ As Mosul Is Retaken

New Zealand has congratulated the Iraqi government on the successful liberation of Mosul from ISIS after a long and hard-fought campaign. More>>

Gordon Campbell: On The Current US Moves Against North Korea

If Martians visited early last week, they’d probably be scratching their heads as to why North Korea was being treated as a potential trigger for global conflict... More>>


Gordon Campbell: On The Lessons From Corbyn’s Campaign

Leaving partisan politics aside – and ignoring Jeremy Corbyn’s sensational election campaign for a moment – it has to be said that Britain is now really up shit creek... More>>


Another US Court: Fourth Circuit Rules Muslim Ban Discriminatory

ACLU: Step by step, point by point, the court laid out what has been clear from the start: The president promised to ban Muslims from the United States, and his executive orders are an attempt to do just that. More>>