The Zebra mussel – Dreissena polymorpha – Mejillón cebra is a species of freshwater mussel native to the freshwater lakes of Eastern Europe and Western Asia. It gets its name from the distinctive striped pattern on its shell, which resembles the stripes on a zebra.
Zebra mussels are small, fingernail-sized mollusks that have become invasive species in many parts of the world. They have also become a significant concern in Spain, were first detected in Spanish waters in the mid-2000s and have since spread to various regions across the country and is present in over 60 reservoirs along with canal systems and irrigation channels. The consequences of these “blockages” range from the inability of a hydroelectric plant to generate power to the inability to irrigate fields when mussels invade irrigation reservoirs.
Zebra mussels filter large amounts of water, which can alter the natural balance of aquatic ecosystems and negatively impact native species. Their accumulation on submerged structures like pipes, dams, and water intake systems can also lead to clogging and increased maintenance costs for infrastructure.
Introduction of Zebra mussel – Dreissena polymorpha – Mejillón cebra into Spain?
The introduction of zebra mussels in Spain is believed to have occurred through the transportation of contaminated boats or equipment, particularly in water bodies connected to international shipping routes. (They may have arrived in the water inside a boat’s engine or in larval form as live bait for fishing) Once established, zebra mussels have the ability to reproduce rapidly and colonize new areas, leading to their widespread distribution. It is one of the most concerning invasive exotic species due to its almost unstoppable expansion, with a million eggs laid each year, causing environmental and huge economic damage.
Efforts to control and manage zebra mussels in Spain include monitoring their spread, implementing measures to prevent further introductions, and developing strategies for their removal. These efforts involve collaborations between government agencies, researchers, and stakeholders to mitigate the impacts of this invasive species.
Part of their successful expansion in Spain is that they require water temperatures of 13 to 14 degrees Celsius for reproduction, which occurs “two or three months a year” in their place of origin but can happen “six or seven months” here in the warmer climate of the iberian peninsular.
In less than 20 years, zebra mussels have gone from being present in just one reservoir to the entire national territory and the challenge now lies in containing their expansion. Complete eradication of the Zebra mussel – Dreissena polymorpha – Mejillón cebra is doubtful.
See a full list of invasive species in Spain here: https://wildsideholidays.co.uk/introduced-and-invasive-species-in-spain/
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