Lluís Cardona, biologist: “If you see pigment, keep calm and walk away quietly”

In just over a week, snorkelers have seen several specimens of blue sharks or blue sharks in the waters of the Costa Brava. The first case was on Bourbou Beach, on July 16, and on Monday two more samples were seen off Gran Beach, which was evacuated for half an hour. Soon after, a surfer noticed the species near the S’Arnella lighthouse, in the same municipality.

The Costa Brava is not the only area in the Mediterranean where this species has been seen this summer. Blue sharks have also been seen off the coast of Menorca, Alicante and Valencia. In none of the cases were the swimmers’ lives endangered, although their presence did cause some scenes of panic.

This summer specimens have been seen off the coasts of Menorca, Alicante and Valencia

Experts don’t know why more blue sharks are appearing in shallow waters this summer. “This year there are more near the coast, which is rare and unusual,” says Lluís Cardona, a biologist from the University of Barcelona (UB), who has ruled out the lack of a causal relationship with the warming of the water. Currently, depending on the region, it is around 25 or 26 degrees Celsius, which is a higher number than last year.

Unlike whales that approach the coast during their migration from the southern Mediterranean to the Gulf of Lion, in the spring, between March and June, this is not typical behavior for the blue shark. Usually, this species is found abroad. “It is a fish of oceanic waters, which during the day can swim below 200 meters and at night rise to the surface.”

This year they were seen near the coast, which is rare and unusual; We don’t know why

Luis CardonaBiologist, University of Barcelona

Those of Portebau were rather small animals, measuring one and a half meters. They can grow up to 3.5m in length, although the average size of fish caught in the Mediterranean is around 1.80m, according to the biologist.

They are solitary animals that do not enter into groups, feeding mainly on small fish and squid. “They don’t eat dolphins or humans,” Cardona says.

“If you see this, calm down, move away from the animal and notify the rescuer,” explains the expert. The blue shark, which has a mouth length of 20 cm, can only bite if it is frightened. “If she is afraid, it cannot be ruled out that she will bite, but it is very unlikely that she will attack,” he says. They are not solitary animals, nor do they go in groups.

One hypothesis of its approach to Earth is that it has some physical problems. But of all the specimens seen so far, in only one case has the lifeless body of the animal been found a few days after it was sighted. “An ocean animal when it gets into trouble can end up on the beach like logs or plastic, so why not swim upstream,” Cardona explains.

“If she gets scared, it cannot be ruled out that she will bite, but it is very unlikely that you will attack her.”

Blue shark abundance has been declining since the 1970s due to overfishing. That year, pelagic longline fishing was introduced in Spain, targeting swordfish and tuna, but many blue sharks also began to be caught, causing a decline.