Scientists, naturalists and fishermen are working side by side to create an innovative device: the implementation of repulsive noises, which would scare dolphins away from trawlers, and hence prevent them from becoming entangled in fishing nets and drowning.
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Worrying figures
Between the months of January and April 2018, data collected by the National Stranding Network recorded no less than seven hundred strandings of small cetaceans, dolphins and other porpoises on the Atlantic coasts. Olivier van Canneyt, a biologist working at the Pelagis Observatory in La Rochelle, is particularly concerned. Van Canneyt’s field of work concerns the study and protection of sea birds and cetaceans.
90% of these alarming strandings were of common dolphins, 70 to 80% of whom died after, judging from the wounds on their bodies, becoming accidentally trapped in fishing nets.
The cetaceans are pulled aboard the trawler by fishermen who, realising the creature is dead, simply throw it back into the sea. The corpse of the marine mammal then slowly drifts along, before eventually washing ashore on the beaches of France.
…and it gets even worse!
Worse still, this figure is three times higher than the numbers of strandings recorded for the past ten years! For alas, not all of the corpses of dolphins and other marine mammals are washed ashore on French coasts by the tide, a fact which makes naturalists think that approximately 3500 dolphins were killed as a result of trawling during the winter of 2017/2018.
How can we explain this increase in the number of deaths of mammals?
It could actually be due to an accumulation of factors.
Climate change has led populations of cetaceans to move further and further towards the Atlantic, whereas during winter they normally swim in the waters of the North Sea. Ultimately, the depletion of fish stocks as a result of overfishing causes some mammals to try to approach trawlers to find food, drastically increasing the risk of becoming accidentally trapped.
Action is finally being taken
In light of the terrible situation, IFREMER, the Pelagis Institute and Les pêcheurs de Bretagne (the Fisherman of Brittany - LPBD) have decided to work together to find a solution to this unnecessary slaughter. They appear to have decided to develop a technology known as Pinger, namely small efficient devices which emit noises at regular intervals and scare dolphins away.
In the meantime, another project is also currently being developed; named Licado, (an acronym for the Limitation of Accidental Captures of Dolphins). By 2021, these new generation Pingers are set to be extremely high-functioning and efficient.
Moreover, the installation of a hydrophone programmed to detect the cries of dolphins will ensure that the Pingers are only triggered when it senses that a dolphin is approaching. The device will then steer the sonar of dolphins towards mammals who, disorientated, will quickly further distance themselves from the fishing zone…
