L. fortunei in Brazil
The golden mussel (Limnoperna fortunei) is a species of bivalve mollusc introduced in Brazil via ballast water in the 1990s. Given the biological and ecological characteristics of the species, as well as the favorable environment in the country for its proliferation, the golden mussel became an alien invasive species. The biological invasion of this species has caused environmental and economic impacts, causing structural and functional changes in ecosystems and human activities in the South, Southeast, Midwest and, lastly, in the Northeast due to the recent detection in the São Francisco.
IMPACTS
The water column, in addition to being occupied by large larval densities, undergoes changes in transparency due to the intense filtration activity of adults, while the hard substrates, once occupied by epifaunal organisms, are totally covered by agglomerates of the golden mussel (recruits and adults), which increases the structural complexity and quality of these habitats, due to the large release of organic material through the pseudofezes. Root decay of emergent macrophytes may reduce the biomass of marginal vegetation, causing loss of habitat for foraging, breeding and sheltering of some species of fish and other organisms
AQUATIC MACROOPHITES AND PERIPHYTHON
Dreissenidae invaders and the golden mussel, L. fortunei indirectly affects the macrophyte and periphery community, leading to increased biomass. These effects are due to changes in water quality, especially as regards the availability of nutrients through the release of faeces and pseudo-faeces
PLANCOTONIC ORGANISMS
The golden mussel, affects the phytoplankton and zooplankton community, causing decreases in density and biomass, changes in composition and productivity. The impact on the phytoplankton community structure tends to be severe considering that the presence of zooplankton has no effect on the grazing of most phytoplankton groups by the golden mussel, which feeds on both zooplankton and phytoplankton at the same time
BENTONIC FAUNA
L. fortunei affects the marginal benthic community, causing an increase in the density and diversity of organisms. Intrustrations on shells of mollusks and bivalves have affected the structure and composition of the taxocenosis of freshwater bivalves, being one of the threats to the conservation of some species .
ICHTHYOFAUNA
L. fortunei affects ichthyofauna due to the greater availability of resources, both for fish larvae and for adult fish. Many fish have changed their eating habits by acting on other trophic guilds, resulting in energetic gain to these predatory species of the golden mussel. Deleterious effects can be cited for fish species, which when fed on mussels without oral apparatus adapted to crush the shells, suffered injuries to the anus due to the passage of the cones, which made them susceptible to the parasites.
WATER QUALITY
Populations of the golden mussel decrease the concentrations of particulate organic matter in the water column and raise the levels of ammonia, nitrate and phosphate, leading to an increase in the Phosphorus / Nitrogen ratio. They also cause increased water transparency, decreased seismic, phytoplankton and primary productivity. The golden mussel, affects the nutrient cycle in the aquatic environment clarifying the water column.
ECONOMIC IMPACTS
Impacts of economic order affect, especially the electric sector, through equipment damage and reduction of generation efficiency. Other affected sectors include fishing, navigation, fish farming and the capture and treatment of water
Electricity generation and reservoirs
The presence of the golden mussel can produce structural damage to cooling equipment, grids, filters, pumps, pipes, racks, grids, screens, storage tanks, pump wells, water inlet tunnels, submerged monitoring instrumentation, level and concrete walls The interval between the shutdowns for the maintenance of the Itaipu turbines was reduced after the invasion of the golden mussel, generating daily costs of US $ 1 million
A 120 MW hydroelectric plant affected by the golden mussel, with three generating units, may have daily costs of R $ 40,000.00 due to machinery shutdown, without accounting for equipment maintenance costs and removal of incrustations
Water collection, treatment and distribution
Water pickup faces major problems with the clogging of valves, pumps and grids by reducing inlet flow. The distribution of water to the treatment plants is also impaired due to the clogging of the pipes. The invading organism still apode enter the treatment plant where when dying as a result of the treatment process, it generates organic residue that must be removed.
Aquaculture and fishing
The aquaculture production in nets is affected by the mollusk, which grows in the nets and other metallic surface of the tank, causing deterioration of the material, water quality, reduction of flow inside the tanks, increase of tank weight, drop in production , fish mortality and shortening the lifetime of the whole apparatus.
Navigation and waterways
Structural damages are also seen in locks on both metal and concrete surfaces. In addition, boats are an important vector of dispersion on these waterways. The transposition of basins increases the connectivity between invaded and non-invaded water bodies, increasing the risk of dispersion through water transport, in which the invading bivalve can be transported both fixed to the hull of vessels and in water storage tanks
Irrigation systems, due to infrastructure conditions, are an important risk factor in L. fortunei colonization. As is already the case in other countries, with other invasive bivalves, the damage caused by the clogging of pipes, pumps, hatches and filters are numerous.
The Map of the Golden Mussel in Brazil, collects the information offered by the Brazilian official bodies and also the records obtained by Ecowater Technologies.
Circles with red alert refer to riverside towns with high risk of invasion of drinking water supply systems. This map will be updated every two weeks.