On August 26 this year, in the Ligurian Sea (located between the French, Italian and Corsican coasts), the team of the company Liguria Whale Watching was able to enjoy an exceptional sighting in the Mediterranean: a humpback whale (Megaptera novaeangliae) about 13 meters long accompanied by its young, 8 meters. This sighting is not only special because it is a mother with a cub, but also because humpback whales are not a common species in the Mediterranean.

The humpback whale is a cosmopolitan species, present in all oceans, and was previously considered a rare species in the Mediterranean. But recently, it is considered an occasional species in our waters, as since 1990 there has been an increase in the number of sightings of individuals of humpback whales, mainly adults and sub-adults. (There is only one record of a possible mother and breeding brook sighted in 1986 in Mallorca waters).

If they don’t belong in the Mediterranean, where do these whales come from?

The whales that have been sighted in the Mediterranean so far are believed to be animals that belong to the North Atlantic population and enter the Mediterranean through the Strait of Gibraltar.

There are different subpopulations of humpback whales in the world, and all of them, except for the subpopulation of the Arabian Sea, make exceptionally long migrations, reaching up to 8,461 km between their feeding areas and breeding areas. Specifically, whales in the North Atlantic population migrate between the cold, productive waters of Iceland, Greenland, Norway, the Gulf of Maine, and the Gulf of St. Llorenç, among others, where they feed during spring, summer and autumn, and the warm waters of the Caribbean and Cape Verde, where they mate and the females give birth in winter.

The reasons why these animals visit Mediterranean waters are unknown, and in recent years several hypotheses have been considered, including the disorientation of animals in their migration or that they are animals that have entered following the migration route of the common whales, but currently the most accepted hypothesis is that they enter the Mediterranean in search of food. In studies carried out by the University of Seville and the area of ​​biological research R+D+i of the Aquarium of Seville, they saw that overlapping the positions of the sightings with maps of primary productivity, the positions of the animals coincided with areas high productivity, indicating a possible relationship between the presence of whales and food availability. In addition, in 2016 it was possible to track an individual sighted off the coast of Algeciras where it was possible to observe behaviours associated with feeding and coincided with a high presence of krill in the area. In this case, in the case of a mother with a child, the reasons are less clear.

Why has the number of sightings increased in recent years?

The increase in the population of humpback whales and possible expansion of its territory and / or the temporary or permanent changes in the oceanographic conditions of the waters of the Strait of Gibraltar and the Mediterranean Sea, which would favour the presence of food for this species, could explain the cause of the increase in sightings of this species in the Mediterranean in recent years.

The current world population of humpback whales is estimated at approximately 135,000 individuals, according to the IUCN, which is 93% of the size of the world’s pre-whaling whaling population. The recovery of the population has been thanks to the ban on commercial hunting in 1986 and the trend of the population continues to rise, despite the many threats it currently faces.

Whale identified 34 years ago in the Dominican Republic

Although we do not know the reason why this mother and baby have entered the Mediterranean, we do know that the mother belongs to the North Atlantic population, thanks to the collaboration between different entities in the Atlantic, Liguria Whale Watching and Menkab, the breath of the sea. Organizations have analysed photographs taken of individuals ’tails and using the photo-identification technique, which uses the colouring pattern and shape of the tail to identify each individual, and have made a very interesting finding. The mother of humpback whale sighted this August in Liguria was first seen 34 years ago, in 1986 in the waters of the Dominican Republic and has not been observed again until last week when she appeared in our waters accompanied by a baby. Until now, it has never been possible to prove that any of the whales sighted in the Mediterranean came from the North Atlantic, and therefore this discovery gives even more value to this sighting.

Given the increase in sightings, changes in climatic conditions such as sea temperature and the increase in the population of this species, there are researchers who believe that the presence of humpback whales will be increasingly common in the Mediterranean and therefore, it is important to start working on establishing preventive measures for conservation and preservation of this species.