Will growing seagrass beds bring back rare sea cows to Chilika?

Jatindra Dash ICT by IANS thaindian.com 1 Mar 10;

Chilika (Orissa), March 1 (IANS) Wild life experts are hoping the highly endangered dugong or sea cow could again come visiting Orissa’s Chilika Lake, thanks to the expanding beds of sea grass growing in the shallow waters - a critical requirement for the big marine animal.

Seagrass meadows are the only marine flowering plants found in shallow waters. They serve as spawning and nursery grounds for a large numbers of fish and invertebrate species, and provide a critical habitat for dugongs and turtles.

The seagrass beds, which also play an important role in the food web of inshore coastal ecosystems, are declining globally.

However, experts have found the seagrass meadows to be expanding in the Chilika Lake, the largest brackish water lagoon in Asia.

The lake, some 100 km from state capital Bhubaneswar, is spread over Puri, Khordha and Ganjam districts. It is home to the largest congregation of migratory birds in the country and also to more than 150 endangered Irrawaddy dolphins.

“The seagrass meadows were only 20 sq km in 2000 in the lake, but it has now expanded to 80 sq km due to various conservation measures,” Ajit Patnaik, chief executive of Chilika Development Authority (CDA), told IANS.

Till date, 58 species of seagrass belonging to 12 genera are known to occur the world over. “In Chilika, five species of seagrass are recorded so far,” he said.

According to Patnaik, the dugong was last sighted in Chilika in 1902. “Unfortunately, they are now extinct from the lake,” Patnaik said.

“We hope the dugongs again come back to the lake as the seagrass meadows are now a common sight,” he said.

The dugong is listed by the International Union for Conservation of Nature (IUCN) as a species vulnerable to extinction. The Convention on International Trade in Endangered Species also limits or bans the trade of derived products in the large marine animal.

The mammal, which has a lifespan of over 70 years, has a slow rate of reproduction and heavily depends on seagrass for subsistence. At birth, a dugong can be around 27.5 kg and an adult could be around 360 kg.

The dugong is threatened by hunting, habitat degradation, pollution and human activities. Their natural predators are sharks, whales and crocodiles.

Commonly found in the Indian and Pacific oceans, dugongs are seen along the coasts of Africa, India and Sri Lanka.

Despite a recent surge in research activity, studies on Indian seagrass are few and inadequate. Large regions and a major stretch of coastlines of the country are still unexplored for sea grass.

“We (CDA) have entered into a Memorandum of Understanding (MoU) with the Leibniz University, Hannover, Germany, to do a study on the seagrass here,” Patnaik said.

Jutta Papenbrock of Institute of Botany, Leibniz University Hannover (LUH), who is a molecular taxonomist, visited the lake along with Matthias Pilz from Cologne University last week and carried out an in-depth study, he said.