Kerala - Kochi

Water bodies under threat from hyacinth

KOCHI: Water bodies in the State face another threat as water hyacinth has proliferated this year, increasing their environmental degradation and loss of biodiversity.

The water bodies in Kottayam, Alappuzha and Ernakulam districts are the worst affected, with the plant covering most of them. Water hyacinth was introduced in the State nearly a century ago as an ornamental variety from Brazil.

Though the State had earlier controlled the spread of Salvinia, ‘African Payal’ in local parlance, through bio-control methods, no control method has been developed for water hyacinth.

Besides affecting the water quality, the plant hampers fishing and navigation through the backwaters. It has become a health hazard by serving as a breeding ground for mosquitoes.

The spread of the plant prevents the penetration of sunlight into the water and reduces the dissolved oxygen content, which affects the primary productivity of water bodies and kill the entire ecosystem, said B. Madhusoodana Kurup, Director of the School of Industrial Fisheries of the Cochin University of Science and Technology.

The spread of water hyacinth has started affecting the State in the form of low catch, reduced number of fish species and dwindling fish diversity, he said.

The root system of the plant has been found serving as an ideal breeding ground for mosquitoes. The plant can reproduce through vegetative methods as well as through seeds, resulting in the speedy growth.

The fast rate of reproduction has made its total removal near impossible. The species can double its biomass in a week, experts said.

The weed has affected backwater cruises for tourists during the peak tourism season, said Peter Panathara, a tour operator.

According to Sunny George, head, research and development, of the Kottapuram Integrated Development Society, who carried out studies on water hyacinth, the plant pollutes the water bodies and lowers its quality.

The decaying biomass of the plant will deoxygenate the water and increases the total dissolved solids. It will make the water unfit for many uses, Dr. George said.

Though the plant is known for its tolerance to high-level pollution, it decays even in mild salinity. However, the decaying biomass will reduce the dissolved oxygen in the bottom layer and choke the ecosystem, he said.

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