The first interactions of various killer whale specimens (orcinus orca) with boats were detected in July 2020 in the Strait of Gibraltar and on the Galician coast, and since then they have only increased and have led the Ministry for Ecological Transition to resort to marking these cetaceans. At the moment, one specimen is already being tracked and the intention of the pilot project is to install a satellite tracking device for five other conflicting orcas in the Strait area. So far this year, the Orca Atlántica organization has detected up to 53 interactions in the area: 12 have reported damage to ships and 31 have corresponded to sightings. A higher figure than other years at the same time, although it is still early to draw conclusions.
In their interactions, the orcas approach different types of boats, “but it is the sailboats that suffer the most damage because they pry the rudder and manage to break it,” says Renaud de Stephanis, coordinator of the Conservation, Information and Study organization on Cetaceans (CIRCE), which collaborates with the ministry in the marking of killer whales. The monitoring will allow us to know the location of the specimens in the last hours and to prepare a weekly map of the approximate area in which they have been moving during that period, says the department of Teresa Ribera in a statement. This information will be shared with the competent administrations, which will disseminate it for the knowledge of navigators in order to try to minimize the risk of interaction, avoiding or reducing navigation through said areas, he adds.
Since the first contacts three years ago, 744 meetings have been recorded in the area between North Africa and French Brittany. Of these, 239 are sightings of orcas in the distance and 505 interactions in which these animals get close, with or without physical contact with the sailboats, indicate the data from Orca Atlántica. In the Strait of Gibraltar live 60 orcas distributed in several families, some of which are conflictive and have been chosen to install the tagging. A month ago, CIRCE placed the mark on one of them. “The device is installed by firing a titanium dart from an air rifle, which is attached to the fin and which we hope will last about two months,” says De Stephanis. On Wednesday they plan to mark the second copy.
The device offers information in real time and “in this way it is possible to notify where the mammal is”, clarifies the CIRCE coordinator. Their exact position cannot be determined because they are constantly moving, but the data allows for prediction models of where they are. The conservation organization has had data on orcas in the Strait for 25 years. “We know what they are,” continues De Stephanis. But with their size – they can measure up to seven meters – they are capable of causing serious damage, even shipwrecks. This May 4, one of the most violent incidents that caused the sinking of the sailboat was recorded champagne, in which its four occupants could be rescued in time. In addition, “they are learning from each other; they push the rudder with leverage until it breaks.” The interactions occur in spring and summer because that is when they are waiting for the tuna, in shallower water. “We have realized that the conflict zone is very small and that it could be avoided,” he says.
Alfredo López, a marine biologist and member of the Atlantic Orca group, explains that the interactions this year have been greater than at this time in previous years, “but we cannot say that they increase until the end of the year is evaluated, since the orcas are changing area and intensity over time. López avoids using the word attack because it is an “ambiguous” term, preferring to talk about interactions. The group calculates that 20% of the encounters become serious and leave the ships impeded for navigation. The team has spent years trying to find the key to the start of these interactions, and they have even published a scientific publication on the matter in the specialized magazine Marine Mammal Science. They are considering the possibility that a first specimen had a traumatic encounter with a boat or a combination of factors, such as the depletion of fisheries or the disturbance caused by boats, combined with the curiosity and intelligence of orcas, capable of transmitting knowledge through of social learning.
The marking works, indicates the ministry, give continuity to the scientific study carried out at the end of 2021 by the Coordinator for the Study of Marine Mammals (CEMMA) and the Atlantic Orca Working Group (GTOA) on episodes of interaction of the population of orcas with sailboats in the waters of Galicia and the Strait of Gibraltar. Among its conclusions, it was urged to test interaction minimization techniques, and to deepen the knowledge about the habits of the species. This pilot project aims to show the different techniques to offer clear guidelines for action, especially for sailboats, which allow their navigation to be safe. At the same time, the development of actions aimed at preventing orcas from getting used to approaching the boats will be sought.
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