• by IPS Correspondents (buenos aires)
• Wednesday, July 11, 2012
• Inter Press Service

BUENOS AIRES, Jul 11 (IPS) - The governments of most of the countries that share the Río de la Plata basin are doing little or nothing to halt the golden mussel invasion, despite the serious damages and losses it is causing.Limnoperna fortunei, an inedible freshwater bivalve mollusk, is native to the rivers and streams of China and Southeast Asia. From Asia, it travels around the world as a “hitchhiker” or “stowaway” on ocean-going cargo vessels. It first appeared in South America in 1991.

With no local predators, golden mussels quickly adapted to the Southern Cone region of South America, reproducing rapidly over the last 20 years and spreading from the Río de la Plata estuary to the Paraná and Uruguay Rivers and their various tributaries, all the way to the Brazilian city of São Paulo.

Biologist Gustavo Darrigran, director of the Invasive Mollusk Research Group at the School of Natural Sciences and Museum of the National University of La Plata, explained to Tierramérica * why the golden mussel’s presence in the region is considered an “invasion”.

“An exotic species is one that is introduced to a new place, whether intentionally or not, and remains where it entered. An invasive species is one that becomes naturalized in its new environment and then quickly and rapidly spreads,” he said.

Darrigran, who recorded the appearance of the first specimens in 1991, stressed that the invasion “is causing impacts on both the natural environment and on humans.” Nevertheless, he added, the concern shown by the region’s governments over these impacts has been only partial.

The mussels attach themselves to any kind of hard surface, natural or artificial, and form colonies that block the pipes and filters of drinking water purification plants, industrial cooling systems, electric power plants and irrigation channels, as well as affecting navigation, tourism and fishing.

“They travel upstream around 240 km a year, an incredible speed considering that they live attached to any available hard surface,” said Darrigran. Just three years after they were first observed in the region, golden mussels had clogged the water intake pipes of a drinking water treatment plant in Bernal, south of Buenos Aires, leading to the need for more frequent and costly cleaning, he said.

By the beginning of the new millennium, the fast-moving mollusks had already reached the Pantanal wetland spanning Bolivia and Brazil. They later wreaked havoc on the Argentine-Paraguayan Yacyretá hydroelectric dam and the Brazilian-Paraguayan Itaipú dam, both on the Paraná River. They have also taken up residence in the Salto Grande hydroelectric dam on the Uruguay River, shared by Argentina and Uruguay.

© Inter Press Service (2012) — All Rights Reserved. Original source: Inter Press Service

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