Net damage caused by dolphins and fishermen competing for stocks revealed
The situation is costing some fishing businesses in northern Cyprus tens of thousands of euros a year, researchers said.
Fishing nets suffer six times more damage when dolphins are around because overfishing is forcing the mammals and fishermen ever closer together, new research shows.
Researchers studied the impact of bottlenose dolphins on fisheries off northern Cyprus and said Mediterranean overfishing had created a “vicious cycle” of dolphins and fishers competing for dwindling stocks.
Fishing businesses in the area are mostly small-scale and the study says damage done by dolphins costs them thousands or even tens of thousands of euros a year.
Acoustic “pingers” designed to deter dolphins were ineffective and may even have worked as a “dinner bell” to attract them in some cases, researchers found. Although it was thought more powerful pingers might work better.
“It seems that some dolphins may be actively seeking nets as a way to get food,” lead author Robin Snape, of the University of Exeter, said.
“This is probably driven by falling fish stocks, which also result in low catches, meaning more nets are needed and higher costs for fishers.
“Effective management of fish stocks is urgently needed to address the overexploitation that is causing this vicious cycle.”
The nets examined, which are weighted to create a barrier about 1.2 metre high on the sea floor, are the most common kind used in the Mediterranean.
When damaged by dolphins, nets may have large sections missing.
Researchers estimate that about 10 dolphins are accidentally caught in the study area each year but under-reporting by fishermen and possible deaths due to swallowing plastic from nets may mean this is an underestimate.
Little is known about this population of dolphins, so even apparently small losses may have a serious impact.
The paper, Conflict Between Dolphins And A Data-Scarce Fishery Of The European Union, is published in the journal Human Ecology.