Invisible predators attacking the Venetian lagoon: “Those tiny animals that are destroying us”

The wave of invisible predators that are damaging fishing in the Venetian lagoon arrived in 2014, before the blue crab and thanks to the heat.

“Sea nuts”

They are small transparent, gelatinous and a few centimeters long animals of the species Mnemiopsis leidyibetter known as “sea nuts”.

The story of the invasion

The research published in the journal reconstructs the history of their invasion and demonstrates the link with the decline in catches in the lagoon. Hydrobiologiacoordinated by the Department of Biology of the University of Padua and conducted in collaboration with the National Institute of Oceanography and Experimental Geophysics of Trieste.

The increase in temperature

The study indicates how the presence of the sea walnut has increased since 2014 due to the increase in water temperatures and demonstrates the negative impact of this species on the small-scale traditional lagoon fishing carried out with cogolli. In fact, it clogs the nets and also devours plankton and larvae of valuable species for fishing.

Reporting from fishermen

The research project was born following a report from fishermen: “They were the first to see the intruder in the lagoon and suffer the consequences”, observes Filippo Piccardi, first author of the research and doctoral student at the University of Padua. “The study”, he adds, “is the first example of quantifying the impact that an invasive species has had and unfortunately is still having on small-scale lagoon fishing. There is not only the blue crab and the risk of these biological invasions is that of the total loss of an almost thousand-year-old lagoon fishing tradition that uses extremely sustainable gear”.

The environmental tragedy

For the research coordinator, Alberto Barausse, “invasive species such as sea nuts and blue crabs are an environmental and social tragedy that must be addressed by seeking sustainable mitigation and adaptation strategies, which also respect local ecosystems which, as clearly shown by research, with their ability to self-regulate in the long term they are our main protection against invasive species.”