During the 12 days that the Ocearch ship – a non-profit organization – sailed from Vigo through the Cantabrian Sea, they came across several blue sharks – on their route, but none of the sharks that were really the target: the white sharks. . “It fits with what was expected,” explains Pablo García-Salinas, a researcher at the Oceanogràfic Foundation of Valencia, who participated in the expedition. The specialists were looking for specimens of this elusive species to tag them, take samples and thus better understand their condition and behavior. Also to try to shed light on whether the white sharks observed in the Cantabrian area are the same as those observed in the Mediterranean.
García-Salinas explains that the first phase of this expedition, the one that took place in the waters of the Cantabrian Sea – it continued along the French coast and will reach the Irish coast – lasted a short time, from the last days of July to August 10. Added to this is the fact that the white shark is an elusive and critically endangered species in Europe and the Mediterranean, so “its numbers are very, very low.” The research approach on the northern coast of Spain stems from the fact that there is reliable data that attests to the presence of these sharks: sightings, photographs, videos. They usually come from fishermen, recreational boat users or people who spot them from a cliff or find a fresh tooth on the shore.
But, says the expert, what is not known is “whether they are there all year round, whether they are only there at specific times or whether they simply use the waters of the Cantabrian Sea as a passage area, a sort of highway between feeding areas or as part of their usual migratory route. That is why the aim was to locate the more specimens, the better – of different sexes and sizes -, to take genetic samples and their body fluids and to tag them with a device that allows them to track their movements almost in real time. Tracing their routes, he says, would allow us to verify whether one of the researchers’ hypotheses is true: that female sharks use the Mediterranean as a nursery to have their babies in waters with few natural predators and that, when they grow up and begin to be able to feed on marine mammals instead of fish, they head towards the Atlantic.
In this part of the expedition, no white sharks have been located, so the mystery remains: “We will continue with the doubt until we manage to catch one and tag it,” explains García-Salinas. The team aboard the Ocearch ship hopes to find them in Ireland, where there are seal colonies. And in the spring of next year, the expedition is expected to enter the Mediterranean. There are several “hot spots in which we can say that they are accumulating.” These are the waters around Sicily, areas near the Tunisian coast and some areas of Turkey. Decades ago, the researcher recalls, they were seen and captured in the Balearic Islands, but not anymore. What remains today are some sightings of animals that are not clear whether they are white sharks or mako sharks, two species that, at some point in their lives, are easy to confuse.
García-Salinas explains that the expedition began in the Cantabrian Sea because it depended on the ship provided by Ocearch, which came from the United States and docked in the port of Vigo as its first stopover in Europe. It was there that the initiative (collaboration of Ocearch, Oceanogràfic and other entities) was presented to the media on July 29. And from there, he headed north with the idea of obtaining samples to examine the genetic profile and see which populations the white sharks that swim in these waters are related to, collect data on their health and put satellite tags on them to know where they are. They move, what areas they prefer and what activity they carry out.
A famous unknown
The researcher points out that little is still known about white sharks, “even though they are the species that comes to mind when you think of sharks,” with the help of Steven Spielberg’s film. The reason for this lack of knowledge is that “generally speaking, wildlife research, despite what it may seem when watching documentaries, is not easy.” At sea, the complications and the sums required multiply, he says, even if technology opens up certain avenues, such as real-time monitoring if a specimen is tagged.
There are also not “as many people who dedicate themselves [a investigar]” to this animal. He reflects, however, that lately, those who study these sharks have the impression that they are becoming “the new dolphins.” They are referring to the growing interest they are seeing from both the public and the academic community. And that, he adds, “is very good.”
A daycare vulnerable to overfishing
The problem with white sharks is the same as with all large sharks: overfishing. García-Salinas says they are caught directly for consumption by humans—or their pets and livestock—and also indirectly. Often, he explains, they fall into fishing nets and end up being thrown back into the sea already dead or used to make fishmeal or for the cosmetics industry.
According to the scientist, “optimistic” estimates indicate that about 100 million sharks are caught each year in the world. Other data speak of a figure of up to double. “There are about 180 sharks per minute in the world. This is scandalous for a species with a very long life, with few descendants, which invests a lot in the development of the offspring,” he emphasizes. They are “very vulnerable” to any rapid change. The Mediterranean refuge eliminates a good part of the natural predators, but not fishing.
The researcher explains that another hypothesis about the Mediterranean white sharks is that they constitute a stable population that does not leave these waters and that they are descended from animals that entered thousands of years ago. Again, to clarify this, it is necessary to be able to track and analyze them.
15 minutes of researcher choreography
García-Salinas explains that Ocearch provides a network of contacts that allows researchers around the world to share information. Although in the Cantabrian phase they were not able to tag any white shark, if they find one in Ireland, Spanish scientists will also have access to the data. The teams, he adds, are interdisciplinary to be able to study genetics, health status, reproduction or parasites that they may suffer from. “Since it is very difficult to access the animal, we wanted to try to obtain as much information as possible,” he summarizes.
The method of capturing a shark is one of the most common in fishing: a line with bait attached to hooks. When one is located, two support boats from the Ocearch ship take it to the side of the ship where there is a platform that lowers to place the animal – to which a water hose is placed so that it can breathe – and then it goes so that the researchers can access it. They have 15 minutes to examine it, collect the fluids and place the satellite tag. “There is a kind of choreography of researchers who come and go to do ultrasounds, take samples of blood, sperm, excrement, take measurements, put satellite tags or that allow us to know permanently what the activity of the animals is, to check their state of health,” explains García-Salinas.
The worst result of this expedition, and the one planned for 2025 in the Mediterranean, would be not to find the animals: it would be an indication that the population is very low. The researcher emphasizes, regarding the fear of this species, that “the most dangerous thing is not to have the shark on the coast, where it should be, but not to have it.”
