In recent years, the Venice lagoon has become the scene of an alarming phenomenon: the uncontrolled proliferation of sea nuts, an alien species that seriously threatens the local ecosystem. This organism, scientifically known as Mnemiopsis leidyi, is causing significant damage, so much so that it has earned the nickname “monster of the lagoon”. The situation has become so critical that scientists, fishermen and local authorities are seeking solutions to contain this invasion.
What are the sea nuts that have invaded Venice
The sea nuts they are technically ctenophores native to the western Atlantic. These gelatinous organisms, similar to jellyfish but without stinging power, are characterized by a transparent and oval body with 8 rows of cilia used for movement. Sea nuts, thanks to the phenomenon of bioluminescenceglow with a blue-green light when stimulated, creating a fascinating but deceptive sight given their destructive impact.
Accidentally introduced in new habitats through the ballast water of ships, sea nuts have found ideal conditions for their proliferation in various parts of the world, including the Venice lagoon. Their presence in these waters has been significantly recorded for the first time since 2014, when the first reports began to raise alarm among experts.
Because Mnemiopsis leidyi is a dangerous alien species
There Mnemiopsis leidyi it is considered a particularly invasive and dangerous alien species in our seas for several reasons. First, his reproductive capacity is impressive: a single individual can produce up to 10 thousand eggs a day in favorable conditions, allowing the population to grow exponentially in a short time. This reproduction rate, combined with the lack of natural predators in new habitats, it makes sea nuts extremely difficult to control.
From an ecological point of view, sea nuts are voracious predators of zooplankton, fish larvae and eggs. This diet has a devastating impact on local ecosystems, as it drastically reduces the food resources available for other marine species, including commercially important fish such as anchovies and sardines. In some areas, such as the Black Sea and the Caspian Sea, the introduction of Mnemiopsis leidyi has led to drastic declines in fish populations, causing serious economic damage to local fishing industries.
Every alien fish in our seas alters the balance and can cause great damage, as in the case of the sea walnut which, by consuming large quantities of zooplankton, greatly reduces the competition for phytoplankton, favoring the proliferation of algae which can in turn cause harmful algal blooms. These events, known as “algal blooms,” can remove oxygen from the water and create dead zones where few life forms can survive.
The situation in Venice is particularly worrying due to the delicate nature of its lagoon ecosystem. Sea nuts, with their ability to adapt to variations in temperature and salinity, have found the Venetian lagoon to be an ideal environment for their expansion. This has led not only to a reduction in local fish resources, but also to a potential ecological imbalance it may have long-term repercussions.
