O Lau Estuary Conservation

Cua Lac Dam, once was home to many resident birds

Where rare species gather

Being born and raised in the Tam Giang Lagoon, Mr. Le Van Nam (70 years of age) living in Quang Thai Commune (Quang Dien) once witnessed the "prosperity" of biological resources in the area of Cua Lac. According to Mr. Nam, during his youth, the areas around Cua Lac Dam were still wild without significant human impacts, so were then endowed with biodiversity values. Around two sides of the dam, a type of cyperaceae were overgrown in excessive heights. Lagoon  areas around Cua Lac Dam were home to a variety of algae species. This was a favorable condition for many aquatic species and rare birds to come and live.

Mr. Nam could not remember specifically how many native and migratory birds lived here, but still recalled some bird names that now sounded "strange" when mentioned, such as coots, teals (anas crecca), etc. Though these rare birds were not in large quantity, farmers often caught sight of them when working in the field. In contrast, rails (rallied), storks, herons were countless. Whenever they came to forage for food, or shelter, Cua Lac Dam was usually covered with a white color. Such highly commercial fish species as grouper/sea bass, eel, swamp eel, “kinh” (in siganidae family), goby ect. had thriven.  Each time going fishing, fishermen could catch up to 10 - 100  kilograms of fish.

Biodiversity resources

Every year, under the impacts of typhoons, floods and human activities, many aquatic species and rare birds in Cua Lac have gradually disappeared, or become difficult to find. According to a survey conducted 20 years ago by domestic and foreign experts, there were nearly 60 species of birds, including anas penelope, teals, coots, spotted redshank, lesser adjutant (leptoptilos javanicus), greylag goose (anser anser) with a number of thousands of these, in which lesser adjutant (leptoptilos javanicus) are listed as rare species in Vietnam’s Red Book, and 22 other species are listed in the category subject to strict protection in Europe. In the last 10 years, these rare birds hardly appeared in the O Lau estuary, and Cua Lac Dam.

The “departure“ of birds is indispensable since resources considered as “their nest" are damaged by fishery and aquaculture. Floating communities of bamboo species (bambuseae, schizostachyum aciculare), acacia, barringtonia acutangula, “sen nuoc” (in Sapotaceae family), climbing fern ( Lygodium microphyllum), reeds, etc. considered as ideal habitats for birds no longer exist. Some clumps of plants like emilliaceae, elusive indica, cynodon, cyperales,  water hyacinth that used to be shelters where birds often landed and foraged for food become scarce.

What to do to conserve biodiversity?

According to a research done by a counseling group of Hue University College of Sciences, the O Lau estuary is a floodplain connecting water from the O Lau River to the Tam Giang lagoon- Cau Hai (Thua Thien Hue). This area has a mixture of freshwater and brackish water, most of which is freshwater during the year.

Originating from a 1,000 meter high mountain in the west of Phong Dien district, the O Lau River is 69 km long with the basin of 746 km2. It is often flooded in rainy seasons, and the humidity in the area during dry seasons remains high, creating a good condition for the development of various vegetation and freshwater fauna and flora. It is also an area with features that are unique to submerged lands. Located within the confluence of river and lagoon with several alluvial areas, the estuary is an ideal habitat supporting a wide variety of aquatic birds, especially migratory birds.

The O Lau estuary is also home to many higher aquatic plants living submerged in water and distributed above, under Cua Lac Dam, and many species of algae etc., which is an excellent condition for aquatic animal residency and proliferation.

Statistics from experts shows that in water surface near Cua Lac, Quang Thai commune only, there are 41 species of aquatic animals and in the lower O Lau area, there are 45 highly commercial fish species such as common carp (cyprinus cardio), mullets, gobies, kinh, carassius etc.  and 21 other species of vertebrates.

Not only domestic but also international scientists are aware of the significance of conservation of biological resources and biological diversity of rare and precious plants and animals in the O Lau estuary.

Head of Natural Resources and Environment Department of Quang Dien District said that there was no better way to preserve the biodiversity at the O Lau estuary than recreating living conditions of these species. Flora, bushes and bird’s landing areas along the O Lau River, Cua Lac Dam should be rehabilitated and restored so birds and aquatic species can reside and seek for foods.

Fishing and production areas must be properly planned to strictly protect resident birds. Fishery activities must be closely associated with resource regeneration.

Director of Thua Thien Hue Department of Natural Resources and Environment, Mr Nguyen Viet Hung stated that the department was implementing a detailed master plan for the conservation site in Tam Giang-Cau Hai submerged lands, including the O Lau estuary. Local authorities have also carried out the planning of the conservation site in the O Lau estuary with an area of ​​70 hectares.

The establishment of conservation sites is a result of a general consensus of involved residential communities, with nearly 80% agreement, creating a favorable condition for the establishment of conservation sites as well as the conservation policies in the O Lau estuary.

Story, and photos: Hoang Trieu