Washington, Feb 5 (Inditop.com) Rampant fishing endangers dolphin populations in the Mediterranean, says a new study.
Aviad Scheinin, who specialises in Maritime Civilisations at the University of Haifa, conducted a study supervised by Ehud Spanier and Dan Kerem, and examined the competition between the two top predators along the Mediterranean coast of Israel: the Common Bottlenose Dolphin (Tursiops truncatus) and bottom trawlers.
These two predators off the coast of Israel trap similar types of fish near the sea floor, so the researchers decided to examine the nature of the competition between the two.
Commercial trawling in the Mediterranean off the coast of Israel targets codfish, red mullet and sole, three commercial and sought-after types of fish.
The fisheries department in Israel’s ministry of agriculture has data showing that over the years the amount of fish from the sea floor looted by Israel’s commercial trawling is larger than the amount of fish that nature provides.
Researchers wanted to find whether this could directly harm dolphins in the sea. They examined the contents of the stomachs of 26 dolphins that died and landed on the beach, or that had been caught by mistake.
Scheinin also examined the behaviour of living dolphins by carrying out 232 marine surveys over more than 3,000 km along the central coast of Israel.
The dolphins’ stomachs contained mainly non-commercialised fish, suggesting that they perhaps do not compete directly with the commercial trawlers, and that the commercial fishing does not directly affect the dolphins’ nutrition.
The living dolphins’ behaviour, on the other hand, draws an entirely different picture. According to Scheinin, most of the dolphins were observed around the trawling boats: the chances of observing a school of dolphins near a trawler is 10 times higher than in the open sea.
“The problem is that this type of fishing endangers the dolphins. Eight dolphins die each year off the coast of Israel on average, and of those, four die after having been mistakenly caught in trawling nets.
“Seeing as many studies have proven the high intelligence of the dolphin, it is clear that these sea mammals are aware of this danger,” he says.
“But they are left with little choice due to their need to search for food around the trawlers owing to the scarcity of other food sources,” Scheinin explains, according to a Haifa release.
