The five herds of killer whales that eat bluefin tuna off Cádiz
The Orca of the Strait Gibrltar before the danger of extinction
Biologists call it Iberian Orca and say that its genetics has not changed in 5,000 years
They spend the winter in the Arctic and 'summer' between the Gulf of Cadiz and the Strait, place of passage of the tuna
Despite its binge of tuna, it is a threatened species. A newly created seaside sanctuary is your last hope
Legends speak of sea creatures that in the summer are whales, but in the winter they become wolves that roam the earth. The cinema and novels, taking the most cruel side of the myth, have put the killer whale poster. Because blood and terror have accompanied killer whales or killer whales since the Phoenicians, masters of the Mediterranean more than 5,000 years ago, described them as monstrous beings capable of even devouring men with their enormous mouths. However, between the Strait of Gibraltar and the Gulf of Cadiz, there lives a type of orca, called Iberian by the biologists who know it best, where these extraordinary beings are born, reproduce and die. There are only five families left. "It is a unique and genetically isolated population of non-distant groups or herds, such as the North Sea or the Canary Islands, whose future is dark," explains Renaud Stephanis, who despite his name and surname is one of the Spanish experts Which best know the orcas of the Strait. These, in spite of the legend that drag their congeners, do not eat whales, sharks, or dolphins, as they do those of Baja California and Patagonia. Nor of course do men eat. Although they share a predilection for the same menu: the coveted bluefin tuna, which they hunt by means of the resistance technique until exhaustion. Once they detect the prey, the orcas are divided into groups of seven specimens that are expected to be spaced from each other by 100 to 150 meters. Already in position, forming a kind of invisible mesh, chase the tunas at high speeds until exhausted, as do wolves on land with their victims. The hunting on the shallow coasts of Barbate or Cadiz usually lasts about 30 minutes. Always above 300 meters deep. Below this level, orcas do not usually submerge. What happens to the trappings that are in the marine area now turned into a sanctuary of killer whales ?, we asked Stephanis. "There will be no problem, fishermen will be able to continue to capture the tuna as they have always done. These killer whales have for thousands of years shared space with the trap." At the head of each of the five families of killer whales, a female, the matriarch, the compass of the herd, which really commands. "Each of these specimens (59 in total) is unique in the world because of its genetic purity despite the fact that today they are seriously threatened," says Renaud. Due to the degradation of their habitat, by the underwater noise produced by cargo ships and tourism, by seismic drilling for scientific purposes, even by viruses, bacteria and parasites that proliferate under the protection of the dirt poured into the ocean. In addition, they are susceptible to other evils, more typical of people, such as Hodgkin's disease, a type of cancer that affects the immune system, and severe arteriosclerosis of the coronary arteries. "A scenario that makes the survival of marine jewelry of which we still know very little," warns Stephanis, who led the research, signed by Dr. Ruth Esteban Pavo (recently awarded the Extraordinary Prize of the University of Cadiz), in which the government of Mariano Rajoy has been based to give green light to the Orca Conservation Plan (Orcinus orca) of the Strait and gulf of Cadiz. It is a sanctuary for the species that occupies 151,061 hectares between the cove of Barbate, Conil and Banco Majuán (an island submerged in the Strait of Gibraltar).
At the head of each herd goes a female, the matriarch. Hunt tunas with depletion technique
"These orcas do not come from other latitudes, they are born and they die in those waters for 5,000 years", explains the biologist Renaud. "That's why, because they have not mixed with other cetaceans, they maintain their own genetics that makes them unique." In charge of its protection - the plan came into force on May 18, 15 years after the scientists gave the first alarm bell - there will now be 10 specialists (six from the Ministry of Agriculture, Fisheries and Environment and four Of the CIRCE group, made up of scientists and university professors specializing in conservation and the marine environment.They have sailed more than 80,000 kilometers and analyzed more than 200,000 photographs of dorsal fins of killer whales, six satellite brands have been deployed to follow cetaceans And performed more than 20 biopsies from which genetic data and residues of contaminants have been extracted.
Studies have been included on the website orca.world). One of the issues that concerns marine biologists is the increase in the levels of underwater noise caused by vessels and, according to studies carried out in this regard, "could lead to changes Of behavior and physical damage to orcas ". For example, "alter or interrupt vocalizations, change swimming and diving patterns or cause injuries to the hearing aid temporarily or permanently that could even lead to the death of the animal. The presence of orca in areas near the beaches It does not miss the locals of Conil, Zahara or Barbate, nor does it provoke, like the films, any kind of social alarm. In fact, they are usually seen only 100 meters from the beach, in the Barbate cove, or 100 Trafalgar lighthouse and the popular beach of Caños de Meca, can breed at any time of the year, have a calf for childbirth, and their survival is tied to the bluefin tuna stock. Which tend to steal tuna from the fishermen in waters close to the Strait. A fifth, which patrols the entire Gulf of Cadiz, follows a mixed diet, eat tuna and other fish.At the risk of extinction all Route is not ruled out, the CIRCE has stored genetic material, DNA, of the orca of the Strait and gulf of Cadiz. "It would never get another equal but at least the species would not be lost," says Renaud.