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Although raising shrimp has helped reduce poverty in the central region, it is also causing many negative impacts on environment, said Dr Nguyen Chu Hoi from the Institute for Economics and Marine Planning.
He spoke at yesterday’s seminar on environmental pollution caused by shrimp farming. The seminar, which was held in central Quang Ngai Province, coincided with World Environment Day ( June 5).
Hoi said the large scale shrimp farms threaten to dry out fresh underground water resources. He also warned that sea water and underground water are often polluted, or become brackish, and the thinning of protective forests (caused by fresh water shortage) causes increased erosion and storm damage.
According to a recent investigation conducted in the central
region, shrimp raised on 300ha for two crops need about 15 million cubic metres of fresh water per year. On a larger scale, 800ha needs about 40 million cubic metres per year.
These requirements are not sustainable for such a hot and dry area like the central region, particularly along coastal sandy areas where fresh water resources are limited.
"Over-tapping fresh water for shrimp raising would cause landslides, and water resources would dry out, directly affecting locals’ daily water supplies and agricultural production in surrounding areas," Hoi said.
In addition, each hectare of a shrimp farm is responsible for producing eight tonnes of solid waste per year. Currently, almost all shrimp raisers dump the shells, excess food and other by-products into the ocean. This pollutes sea water along coastal areas and destroys valuable marine resources—including bathing beaches and national parks.
Many shrimp farmers also eliminate used water by dumping it in surrounding areas, causing underground water and ponds to become brackish. Shrimp diseases are also spread from pond to pond this way, Hoi said.
Hoi outlined several solutions. He suggested that special priorities should be given to businesses that pay close attention to environmental protection by constructing solid concrete ditches and water drainage systems.Authorities should manage the planning, appraising and licensing of various aqua-product projects, including shrimp farming.
Environmental impact assessments should be carried out on shrimp raising projects, focusing on fresh underground water reserves, to provide a legal basis for farm limits. In addition, environmentalists should monitor the areas around shrimp ponds and advise farmers on how to prevent environmental degradation.
Shrimp farmers should build a waste treatment system to avoid leakage in surrounding areas. For sustainable development, they should also construct fresh water reserves to tap rain and surface water from rivers and streams, while trying to use less underground water.
Salt flat shrimp farms in the central region include Ninh Thuan (200ha in total), Quang Ngai (60ha), Thua Thien-Hue (16ha), and Quang Tri (6ha), based on figures compiled mid-year 2002.
However, major projects (more than 100ha per project) are located in the central province of Ha Tinh’s Thach Ha and Cam Xuyen districts and Quang Binh’s Quang Ninh and Le Thuy districts.
Farmer Tran Ngoc Hien in the central coastal province of Ninh
Thuan earned VND400 million from his first harvest when he netted almost all 11 tonnes of shrimp for each ha of his total 15.6 ha last year.
Concerns about over-exploited sea resources and potential economic and social ramifications recently spawned a publicity month on sustainable sea development.
Many international organisations have offered to help Viet Nam in sea preservation, with US$3 million in aid committed so far in support of the formulation and implementation of Viet Nam Agenda 21.
VNS - (07/06/2004)
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