As Ecuador faces the effects associated with the arrival of El Niño, signs of unusual ocean conditions are raising new questions. Between October 2025 and July 2026, a team of scientists surveyed areas of the Galápagos where blue whales have historically been recorded. However, despite continuous search efforts, they did not find a single individual.
The expedition was carried out as part of the work of the Galápagos National Park Directorate and was led by Daniela Alarcón and Juan Pablo Muñoz, researchers from Universidad San Francisco de Quito (USFQ) and the Galapagos Science Center (GSC), in collaboration with the World Wide Fund for Nature (WWF Ecuador) and with support from specialists at Oregon State University and the University of Wisconsin. The surveys covered the waters surrounding San Cristóbal, Isabela, Fernandina, and Santiago islands, with particular attention to the Bolívar Channel, an area known for its historical blue whale records and high marine biodiversity.
Although the main objective—locating blue whales to deploy satellite transmitters and better understand their migratory routes—was not achieved, the team collected oceanographic data through temperature measurements and plankton samples.
During the expedition, sea surface temperatures ranged from 25.52 to 27.56°C, while temperatures at a depth of 100 meters ranged from 19.11 to 19.67°C—high values for this time of year. Between June and November, during the cool season, sea surface temperatures generally range from 19 to 24°C in the central and eastern archipelago and from 16 to 22°C in the western region, including the Bolívar and Fernandina channels.
Water-column profiles confirmed this trend. The 20°C water mass, or isotherm—which is usually found at depths of 20 to 45 meters within the archipelago—was located much deeper during this expedition, between 78 and 96 meters. The temperature range in which blue whales feed remained near 60 meters, below the layer where their food was concentrated. Their food was concentrated at one depth, while the whales’ ideal temperature was found at another.
These measurements were recorded under exceptional ocean conditions. In late August, Ecuador declared a nationwide Red Alert due to the potential effects of El Niño. During the same period, sea-level anomalies of up to approximately 40 centimeters above normal values were reported at some coastal and island monitoring stations.
“Not finding whales during an intensive search effort does not mean they have stopped coming to the Galápagos. By combining these records with oceanographic data, we can begin asking better questions about the conditions that determine their presence and how much their movements may vary,” said Daniela Alarcón, scientific lead of the expedition and professor and researcher at Universidad San Francisco de Quito and the Galapagos Science Center.
In 2025, 45 blue whale sightings were recorded under a standardized monthly monitoring protocol, with August accounting for the highest proportion of sightings during the season. The current season is not yet over, and scientists caution that this absence cannot be attributed to El Niño, nor can it be considered evidence of a permanent change in migration patterns.
In fact, in early September, following the expedition, the Cetácea Galápagos citizen science network reported an adult blue whale with its calf at Punta Pitt, San Cristóbal. The sighting was documented by naturalist guide Isis Lara and Captain Edwin Buenaño. This record reinforces the need to study variations in the whales’ arrival times and the areas they use throughout the Galápagos.
Answering these questions has implications beyond the archipelago: blue whales migrate thousands of kilometers to feed, reproduce, and raise their young. In the Eastern Pacific, part of the population that feeds in Chilean waters migrates toward Peru and Ecuador, although much of this route remains poorly understood.
“To conserve the largest animal on the planet, protecting only the places where we are able to see it is not enough. We need to understand and protect the entire route that makes these encounters possible. That is the scale at which whales move, and it is also the scale at which we must approach their conservation,” said Yacqueline Montecinos, leader of WWF’s Eastern Pacific Blue Corridor initiative.
This expedition was part of the Eastern Pacific Blue Corridor, a regional initiative led by WWF to advance scientific knowledge and strengthen the conservation of migratory routes connecting critical habitats for large cetaceans across the Pacific. Understanding these movements will help guide measures to reduce threats such as vessel strikes, interactions with fisheries, pollution, and underwater noise, while maintaining connectivity among the habitats whales need to survive.
