The impact of climate change in Venice is not limited to the sea’s advance over the city, and there is an alert. The warming of the Adriatic is profoundly altering the lagoon ecosystem, key to the local identity and economy.
While the rising sea level threatens to render obsolete the barrier system that protects the city, the arrival and proliferation of invasive species jeopardizes biodiversity and fishing activity.
Among the most alarming cases is the cannibalistic ctenophore (warty comb jelly or “sea walnut”), considered one of the 100 most harmful invasive species in the world. This gelatinous invertebrate, capable even of feeding on its own offspring, has been present in the Adriatic for almost a decade.
A study by the University of Padua and the National Institute of Oceanography and Applied Geophysics (OGS) warns that climate change has created ideal conditions for its expansion in the Venetian lagoon. According to researcher Valentina Tirelli, large aggregations could form with serious repercussions on the ecosystem’s functioning.
Reproduction peaks are recorded towards the end of spring and between the end of summer and the beginning of autumn, associated with rising water temperatures and adequate salinity levels. The species is a voracious predator of zooplankton, fish eggs and larvae, and bivalves, directly threatening species of high ecological and economic value.
The advance of the blue crab
Adding to this scenario is the expansion of the giant blue crab in the northern Adriatic. Originally from other regions, it is believed to have arrived in the 1940s in the ballast water of ships. Although its presence is not new, its population has grown rapidly in recent years, favored by the absence of natural predators and the increase in water temperature.
“The warming has made them more active and voracious,” a local fisherman reported. Marine biologist Enrica Franchi explained that now the blue crab finds ideal conditions throughout the year. With its strong pincers, it preys on clams, mussels, oysters, and the traditional Venetian moeche, as well as breaking fishing nets.
Impact on fishing and local culture
In response to this advance, proposals have emerged to commercialize the blue crab as food, even incorporating it into local menus. However, specialists and producers warn that this strategy could affect the fishing and culinary traditions of the Adriatic, endangering techniques and knowledge related to native species.
The proliferation of these invasive species reflects how climate change and the globalization of maritime transport are transforming coastal ecosystems. In Venice, the situation is especially critical because the lagoon not only supports biodiversity but also the fishing economy and cultural identity of the city.
The alert in Venice over the invasion of cannibalistic jellyfish and blue crabs shows that climate change not only threatens with floods but also with the loss of ecological balance. The expansion of these exotic species hits local fishing hard and poses the challenge of designing control strategies that protect both biodiversity and the region’s cultural traditions.
