A young sperm whale made a hazardous journey across the Mediterranean to the eastern Mediterranean off Israel’s coast despite many threats facing ocean animals, according to researchers at the Greenpeace organization, the University of Haifa, and the University of Exeter in the UK.
They also observed Cuvier’s beaked whales and bottlenose dolphins, including a young adult sperm whale previously seen off southern France.
The distance between sighting locations made this the furthest-recorded movement of a sperm whale in the Mediterranean, which means the whale made a hazardous journey.
The Mediterranean is one of Earth's most highly impacted enclosed seas, bounded by heavily populated coastlines. Local marine mammal populations are subject to a suite of threats, including anthropogenic noise, other pollution, and poor fisheries management.
“Marine life in the Mediterranean faces numerous threats – from fishing and pollution to noise and boat strikes,” said ecology researcher Dr. Kirsten Thompson from the Greenpeace Research Laboratories at the University of Exeter.
Thompson said, "The Mediterranean is the busiest sea in the world, with rich wildlife and a high human population. Unfortunately, some species like these threatened whales are facing further industrial development, with oil and gas exploration and constructing a new gas pipeline between the eastern basin and Italy. Some argue that further hydrocarbon extraction is a violation of EU environmental protection legislation. This expansion is not just bad for our future climate targets but for the wildlife that is already struggling in this busy sea.”
Relatively little research has been done on whales and dolphins in the Eastern Mediterranean. In this study, visual-acoustic surveys were conducted during April and May 2022 onboard the SY Witness, a 22.5-meter-long sailing vessel, using both sail and motor at a mean survey speed of six knots across both surveys.
Underwater plains and trenches
The Mediterranean contains extensive deep underwater plains and trenches bounded by slopes that provide important habitats for deep-diving cetaceans, such as sperm whales (Physeter macrocephalus) and Cuvier’s beaked whales (Ziphius cavirostris).
Analyses of sounds made by the creatures provided further evidence that whales off the Israeli coast are part of the wider regional population, as their vocalizations matched the unique “Mediterranean dialect” that they sounded. The researchers say their findings demonstrate the need for targeted protection at key locations.
Greenpeace, which funded the research, describes itself as a global network of independent campaigning organizations that “use peaceful protest and creative confrontation to expose global environmental problems and promote solutions essential to a green … future.”
“The journey of this particular whale must have gone through narrow straits – either the Sicily Channel or the Strait of Messina, both of which are extremely busy, noisy, and potentially dangerous for a deep-diving sperm whale,” said Thompson.
The whale—with various names such as Kim, Elia, and Onda, depending on the researchers in different regions—was probably traveling with other young males, who typically leave their birth group at this stage of their lives.
“The fact that these whales pass through narrow, shallow seas means that listening devices could be installed at those points to protect them,” she added. “This could create an alert system to prevent ship strikes.”
Acoustic detections found three encounters with sperm whales, one with Cuvier’s beaked whales, one with a bottlenose, and 17 with unidentified dolphins.
The paper, just published in the journal Aquatic Conservation: Marine and Freshwater Ecosystems, was entitled “Threatened cetaceans off the coast of Israel and long-range movement of a sperm whale.”
Research in the western Mediterranean has shown that sperm and Cuvier's beaked whales are present as small, globally distinct populations that face numerous threats.
The eastern Mediterranean has not been well studied, and few surveys have investigated the composition of cetacean communities. In this study, visual-acoustic surveys were conducted off the coast of Israel during April and May 2022 to characterize the cetacean community.
Sperm whales were foraging about 10 kms off Haifa, at 370 to 1,220 meters deep. Social vocalizations (codas) corresponded to the Mediterranean dialect. One immature male photographed is known from 12 previous encounters in the Ligurian Sea, indicating a west-east movement of approximately 2,800 kms.
The authors wrote that significant research efforts are now being made to better understand sperm whale abundance, population trends, and social behavior. Genetic data show that there is a distinct subpopulation in the Mediterranean that is listed as endangered by the International Union for Conservation of Nature (IUCN), with fewer than 2,500 mature animals. Threats in the Mediterranean include ship strikes, interactions with fisheries, underwater noise from seismic surveys or military operations, and ingestion of marine debris.
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