Blue crab: do sonic deterrents work? Test results.
'We have been experimenting with sound deterrents for at least a year. The tests are ongoing, we are trying to understand the effects on the blue crab , how effective the system, the sound barrier, is', Virginio Mantovan , 59 years old, entrepreneur, former deputy mayor of Porto Viro is part of the task force that from the front lines carries on the battle against the alien that has emptied the clam farms, the income and savings of fishermen from Porto Tolle (Veneto) to Goro (Emilia), from Scardovari (Rovigo) to Gorino (Ferrara).
Two regions, thousands of families left with nothing, a handful of shells. The task force includes Mantovan, a clam farmer, ISPRA, and the University of Padua.
The experiment is one of the items in the comprehensive plan by Special Commissioner Enrico Caterino to combat the blue crab, involving the government, regions, municipalities, and fishing associations. And those conducting research.
"We must understand that everything, every piece, is part of the mosaic of initiatives to halt the crab's advance. Funding is essential, and research is crucial. That means fences, nets, and traps . But also systems, still experimental, to help the crabs escape. The project is the result of a strong collaboration, which in a certain sense also ties us to the tests being conducted for the other deterrent system, based on light effects, developed by the University of Venice ," Mantovan specifies. "In short, we are proceeding in parallel. Meanwhile, millions are being put on the table by the commissioner and the regional governments for this war that has now been going on for over two years. It was May 2023, and in a handful of nights, nothing remains of the clam farms."
How does it work? We use three frequencies, sound waves that travel through the sea. Different frequencies to avoid the risk of the crabs getting used to the disturbance, as happens when they use sound guns to scare away geese. They get used to the roar, the bang, at most they take flight and then they're back there. I'd like to point out that it's a patented system, but precisely because the testing is ongoing, none of these devices have been given to fishermen. We need the green light from the research institutions that are working with us on the project, namely ISPRA and the University of Padua.
We'll discuss it at the end of the tests, once its effectiveness has been proven. If it is proven to be effective. Vadis Paesanti is the vice president of Confcooperative Fedagripesca Emilia Romagna , a fisherman and a man of the sea. He's the one who warns against what he calls a Babel. "We must await the results of the official trial, the one they're carrying out under the direction of the commissioner. Only when the outcome is positive, if that is the case, can we proceed with this tool. Furthermore, the audible deterrent should be compared to nets, fences; it must be fully functional. At that point, it will also be possible to implement a process that will lead to compensation for those who bought it, and assistance with their investment."
This is no small investment. Help yourself and God will help you! Some fishing cooperatives and fishermen have turned to the market, where everything is available, even deterrents. And they've purchased them for prices ranging from €2,000 to €7,000, depending on the model.
A significant expense, which adds to a serious crisis. Some have purchased acoustic deterrents , placed them in water, and achieved no results.
I set up crab traps around to see if they would work. It didn't work at all; there were crabs in the cages. One had landed right on the sound deterrent. I dumped it on the bottom of the sea; it's no use.
These are probably DIY models, perhaps equipment made by novices who have recently entered the sector, driven by easy earnings.
"Building a deterrent is a serious undertaking; it needs to be tested. What we're doing is scientific research in every sense of the word." Marika Bugnoli, mayor of Goro, the town with the most victims.
With clams almost gone, 250 fishermen have given up their profession, five cooperatives have thrown in the towel. Some have even sold their boats, sold them off.
Prices have plummeted . "As I told the commissioner, I hope there are deterrents that can at least deter the crabs," the mayor expressed his hope. The road to recovery still seems long.
İl Resto Del Carlino
