Dear all, Since July, thirty-three interactions of killer whales with sailing boats have been registered: six in the Strait of Gibraltar, then five on the Portuguese coast and finally twenty-two since mid-August, in Galicia, northern Spain. The boats that were targeted by the killer whales during the interactions were later inspected to better understand how the interactions occurred and what type of contacts took place. The interactions were mostly limited to the rudder of the boat, with marks found on the hull or signs of physical contact of the animals with the structure of the vessel. Only 15% of the encounters with the killer whales were classified as interactions which resulted in some kind of damage to the sailboats. In any of the interactions, people were never endangered by the direct activity of the killer whales. However, there were some risky situations during night-time and long-lasting interactions, due to abrupt movement of the steering wheel or turns of the boat, which caused distress to the crew members due to their lack of experience with killer whales and their behaviour. *International Working GroupA Group of Experts thoroughly investigates the trail of orca interactions* An international Working Group (WG) of cetacean experts and competent administrations has been set up, with great knowledge of the casuistry and behaviour of orcas. The WG has been analysing each and all cases in great detail and is in permanent contact with SOS-Galicia, Salvamento Marítimo (Spanish Lifeboats), the Spanish Ministry of Ecological Transition and the Demographic Challenge (MITECO) and the Xunta de Galicia (Regional Government of Galicia) to compile all the available information. The scientific group is made up of Dr. Alfredo López from the Universidade de Aveiro-CESAM, Mr. Jose Cedeira from CEMMA; Mrs. Cristina Martín from TURMARES Tarifa, Mr. Ezequiel Andréu Cazalla from the Garum Tarifa Association, Mrs. Rocío Espada from Ecolocaliza and LBMarina from the University of Seville, Mr. Francisco Martinho from ECCO Ocean, Dr. Marisa Ferreira from SPVS and Dr. Ruth Esteban from the Museu da Baleia da Madeira and Ocean Sea. Institutional members include Mrs. Elvira García Bellido from the Spanish Ministry for Ecological Transition and the Demographic Challenge and Mrs. Marina Sequeira from the Instituto da Conservação da Natureza e das Florestas de Portugal. The information used by the WG is based on more than 700 records of killer whales on the Iberian coast in the last 20 years compiled by CEMMA, Dr. Ruth Esteban, Mr. Francisco Martinho, SPVS and especially Turmares Tarifa. *IdentificationThe GLADIS, involved in the interactions, are young killer whales known in the Strait* During the different interactions, up to 3 different individual killer whales have been identified as directly involved in the events. These animals were observed near the sailboats, and were identified in 61% of the interactions thanks to photos and videos taken by the crew that were sent to the working group. In addition, in some interactions, two other adult individuals were observed further away from the ship, and have not been identified so far, but are considered as most likely not involved in the interaction. The three interacting killer whales have been named the GLADIS (BLACK, WHITE and GRAY) and all were observed from June to August of this year in the Strait of Gibraltar. Additionally, two of them (BLACK and WHITE GLADIS) had already been observed in previous years in the area. In the Strait of Gibraltar, individuals have been observed relatively frequently with injuries caused by the friction with fishing lines when they try to “steal” tuna already hooked on the longlines. The two GLADIS (BLACK AND WHITE) observed in the Strait of Gibraltar this year presented injuries consisting in marks appearing successively on their bodies and more intensively between the 20th of June and 3rd of August. The WG has mapped and described the injuries on a representation of the body of each specimen, to try to clarify their origin, hoping they can offer clues towards an explanation for the interacting behaviours. All marks identified as of anthropogenic origin or open wounds with doubtful origin were systematically registered. The observed marks were meticulously detailed based on the underwater photographic series provided by the Scientific Department of Turmares Tarifa. The photographs of the orcas located by Francisco Gil were taken by photographer Rafael Fernández Caballero, with the permission of MITECO. *CausesThe trigger for this behaviour could have been an adverse incident* In the Strait of Gibraltar, juvenile killer whales are commonly observed approaching boats of various kinds, likely due to their curiosity. The stern is especially as there are mobile and noisy structures. However, the interactions with sailboats detected since July in the Strait, Portugal and Galicia are considered unprecedented due to the repeated physical contact of the specimens with the structure of the ships. Although the approach and beginning of the interaction are similar to other previously observed encounters with boats, the GLADIS showed an unprecedented novel behaviour consisting in physical contact with the weakest structure of the ship, the rudder, which sometimes led to breaking partly or completely the rudder. The trigger for this strange and novel behaviour could have been an adverse incident between these killer whales and a boat. At the moment there is still no clear evidence of when or if it actually happened, and the WG cannot confirm what type of ship could be involved, or if the incident was accidental or intentional. However, given the lack of evidence, the WG cannot rule out either that the novel behaviour could be induced by the juvenile orcas’ own interest and curiosity, since by touching moving parts of the boat they can move or even stop a large moving object. Kind Regards, Ruth Ruth Esteban, PhD. +34675837508 +351912847395