What does it mean to block the clam

The approximately 3 cm large zebra mussel (Dreissena polymorpha) belongs to the mollusc class Bivalvia and is similar in appearance to the common mussel. Due to the explosive reproduction of these mussels, which occurs after the introduction of this species in a body of water, it is practically impossible to prevent the colonization of natural and artificial freshwater substrates. The basic food of the mussels is the phytoplankton, for which they compete with other indigenous species and thereby damage the ecological balance. Their excretions cover the bottoms of the rivers and reservoirs with a layer that is toxic to humans and also kills the entire fish population in the affected water catchment area. Their ability to spread like colonies enables this type of mussel to block irrigation ditches, inlet and drainage channels in power plants, hydraulic engineering systems of all kinds, turbines, sewers and reservoirs, make ship engines and anchors inoperable and completely block water treatment systems, irrigation ditches, canals and pipelines. In the early 1980s, the mussel species spread in the Great Lakes area of ‚Äč‚ÄčNorth America. Efforts to control the species have already cost $ 2 billion, but despite these large investments, the mussel species has fully assimilated.

In the summer of 2001, the occurrence of the zebra mussels was discovered for the first time in the Ebro (Riba-Roja reservoir and in individual sections from Flix to Xerta). Within a few months, the species had spread from the Riba Roja reservoir to the Ebro Delta. Recently, as a result of normal water use, the mussels were also found in the irrigation system of Les Garrigues and Terra Alta, which is more than 20 km from the original range of the mussels.

1. Is the Commission aware of the steps the Spanish Government has taken to eradicate this plague?

2. Are these measures one hundred percent efficient? If not, what measures would be 100% effective?

3. Will the Commission support the financing of the National Hydrological Plan, which provides for the diversion of the contaminated waters (the Ebro) to other water catchment areas?

4. Is such a water diversion legally permissible under these circumstances? Isn't it in breach of the Habitats Directive, which bans the introduction of non-native species?

5. Does the Commission intend to issue an opinion before or after this plague is cleared up?