Haifa University researcher documents longest ever journey of sperm whales in Mediterranean

The longest ever journey of a sperm whale has been recorded by a team of international researchers led by Dr. Aviad Scheinin of Haifa University, according to a study published in Aquatic Conservation: Marine and Freshwater Ecosystems on Tuesday morning.

According to the study, the researchers used photo-identification and comparison with catalogs across the region to provide evidence of the journey of the whale - a young male - among others. The whale was tracked in the wider Mediterranean Sea, with a distance between sightings of 2,800 kilometers (1,740 miles). This is said to be the first documented example of a long-range eastward movement of an immature male sperm whale from the Ligurian Sea to the easternmost area of the Levantine Basin. 

Dr. Scheinin — an Apex Predators Principal Investigator at the University of Haifa — along with University of Exeter and Greenpeace Research Laboratories' Kirsten F. Thompson and Jonathan Gordon of the University of St. Andrews, used passive acoustic monitoring and a non-systematic visual survey to generate data on the presence and ecology of cetaceans within Israel’s exclusive economic zone (EEZ).

Two surveys were conducted during April and May of 2022 onboard a 22.5-meter sailing vessel supplied by the environmental non-profit Greenpeace. 

About eight sperm whales were acoustically detected, but one in particular, deemed an immature male based on its size and characteristic head shape, was photographed and compared with eight Mediterranean photo-identification catalogs. The catalogs confirmed that this same whale had been seen on 12 earlier occasions, with the longest distance between sightings being 2,800 kilometers. This marks the longest documented movement of an individual sperm whale in the Mediterranean.

The researchers reported that a sperm whale would likely have a specific incentive to travel such a long distance between narrow and relatively shallow habitats, and that this travel pattern could reveal opportunities to use targeted new feeding grounds.

How acoustic tracking can help the whale community

According to their study, real-time passive acoustic tracking of individual whales could help to prevent collisions, and inter-basin-traveling sperm whales produce foraging clicks when passing in these pinch points, a method that could be critical for reducing death rates in these areas.

“The gap of knowledge of marine life in offshore waters in the Mediterranean is tremendous,” Dr. Scheinin said. “Spotting these sperm whales is important to our knowledge about biodiversity because if a whale is willing to travel such great distances at considerable risk, then it means it must have found a diverse and lush source of food. Being apex predators of the deep sea makes them important bioindicators.”

Because it is surrounded by heavily populated coastlines with constantly rising temperatures, the Mediterranean Sea is considered one of Earth's most highly impacted enclosed seas. Noise pollution, as well as poor management of fisheries, are just a few of the poor conditions that make the Mediterranean an early-warning model system that shows the future trajectory of climate change in oceans worldwide, according to the research.

In many regions, sperm whales’ population numbers, distribution, and the threats they face remain poorly understood. Now, thanks to this team’s findings, the Israeli Ministry of Energy has requested Dr. Scheinin conduct additional offshore marine mammal research.

“Hopefully, this is a starting point of long-term research on the EEZ,” Dr. Scheinin said. “I hope we will better understand offshore marine mammals in our backyard and explore biodiversity in our Mediterranean Sea. This is a dream I have been waiting to fulfill for twenty years!"