Cannibal jellyfish have invaded one of the most visited cities in Europe
It’s a famous Italian city that attracts up to 30 million visitors every year, but now Venice’s world-renowned waterways are welcoming a new type of tourist.
Cannibalistic jellyfish have made the Italian city their new home and disrupted native fish populations wreaking havoc on fishermen’s trade.
They are considered one of the 100 most harmful invasive species across the world.
The warty comb jellyfish, nicknamed the sea walnut, is known to gobble up its own offspring and has a transient anus that only shows during defecation.
The squishy creature usually lives in the western Atlantic, which stretches from the Arctic to the southern tip of South America, but has recently been found in the Adriatic Sea.
It’s thought that they crossed the globe and invaded Venice’s waters after being accidentally transported there in boats’ ballast water, which is the part of a ship’s tanks that stores seawater to stabilise the vessel.
Scientists have also warned that its recent colonisation of the Adriatic is due to warmer seas brought on by the climate crisis. Researchers said in a report that populations of the jellyfish bloomed in late spring and between late summer and early autumn.
They said: ‘These blooms are likely influenced by elevations in temperature and optimal salinity levels.’
(Picture: Getty Images)
Their takeover of Venice’s lagoons has caused a headache for fishermen. Venice’s fishing industry is worth billions of euros.
The gelatinous fish clog fishing nets but they’re also a fearsome predator.
The warty comb also eats fish eggs, larvae and plankton, which are essential to flourishing life in a lagoon ecosystem.
Scientists from the University of Padua and the National Institute of Oceanography and Applied Geophysics published a two-year study on the impact of the invasive species in Venice.
In the report, scientists said: ‘Ongoing climate change could create increasingly favourable environmental conditions for this ctenophore, potentially boosting its presence in large aggregations and, consequently, increasing the risk of impacts on the entire lagoon ecosystem.”
The warty comb joins another invasive species in the area: Atlantic blue crabs.
They prey on seafood like clams and mussels which are some of the area’s main targets for fisherman.
Italians have responded to the challenge by adding blue crabs to their menus. You can buy cheap blue crabs from fish markets in the country.
Erica Zelante of the Michelin-starred restaurant Venissa in the Venetian lagoon area told The Telegraph: ‘The boom in crab numbers really began about two years ago. We started seeing a lot more of them here in the upper Adriatic.
‘Our chefs decided that it would make sense from an environmental point of view to start using this invasive species.’
The fine dining restaurant uses blue crab with saffron, chillies and spaghetti.
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