Research expedition: Whales of the Aegean

Archipelagos’ marine research team’s autumn research expedition for the recording of east Aegean marine mammal populations was completed at the end of November. The expedition was carried out in cooperation with expert scientists from European universities and its subject was the sperm whale (Physeter macrocephalus). This species has been migrating for thousands of years, cruising across the Aegean, embellishing the Greek seas.
The Archipelagos’ research boats ‘’Nireas’’ and ‘’Pinelopi’’ were used for the purposes of the expedition, as well as a local boat, which voluntarily participates from time to time in the Archipelagos’ activities. The research areas included Central, North and East Aegean and in particular the area from Amorgos up to the pass between Mykonos and Ikaria islands (west of Chios). The deep sea canyon in the area between Chios and Ikaria was also included. During the expedition, more than 2000 nautical miles were covered, and 27 individual sperm whales were recorded in 49 sighting surveys (Watch the video here). The number, gender, age group and migratory behaviour of the populations were recorded. Furthermore, photo identification, acoustic recording and processing of communication sounds were carried out.












Sighting and acoustic recording of a sperm whale pod

The study of these rare marine mammals, had always faced difficulties, due to the specialised physiology and behaviour of the sperm whales (it is a species that migrates continuously and spends a lot of time under water, at great depths). As a result, the coordinated and structured efforts from 3 boats and a large number of researchers and volunteer scientists, was needed.
The data collected will be added to the research carried out by Archipelagos. This research, on marine mammals in various areas of the Greek seas, has been ongoing for the last 12 years. Its aim is to offer an as far as possible complete image of the state of the populations of these rare species in our seas.

Sperm whales in the Greek seas continue, even nowadays, to be an unknown species to the public at large. This reveals the lack of knowledge on this unique enclosed sea and the rare flora and fauna it supports. Although the international scientific community recognises the fact that the Greek seas, and particularly the Aegean, support the most important remaining marine mammal populations in the Mediterranean, the lack of basic conservation measures, in combinationwith the low level of environmental education, constitute grave scenery for the survival of this very important natural and historic legacy.
The particularly intense traffic of commercial vessels without substantial centralised control, the lack of an effective plan for dealing with a possible marine accident and the ever increasing pollution of the marine ecosystems does not leave much room for optimism. In order to be able to prevent or adequately deal with a possible distractive marine accident the immediate application of substantive and operational measures for the protection of the seas (as applied in most of the developed countries around the world) is a must.












The sperm whale comes to the surface to breath and remains there for about 10 minutes

We have a duty to realise that the future of the sperm whale and of the other rear species of the Greek marine ecosystems is at stake every day and over the last decades depends on purely fortuitous factors. The dangerous and irresponsible behaviour, combined with the premeditated transfer of environmental concern to other areas of the globe, are a constant threat to the length of the life expectancy of the Greek marine richness.

The biology of the sperm whale (Physeter macrocephalus)
The sperm whale is the largest marine mammal, which one may encounter regularly in the Greek seas.

The male sperm whales can exceed 18 metres in length and 50 tons in weight, while the female grow to an average length of 12 meters and have an average weight of 20 tons. Despite their huge size, they pose absolutely no threat to humans.

It is a migratory and pelagic species, and its life expectancy exceeds 70 years. The females of the species form into social groups with the younger animals while the males leave on their own.

The sperm whale is characterised by its ability to dive to depths in excess of 2000 metres and it can stay under the water for more than 1 hour. It emerges to the surface and stays up for about 10 minutes so as to get the necessary breaths before the next dive. It stands out for its particularly developed brain, for its compound communication ability and its complex social behaviour.

It feeds mainly on species that are beyond human exploitation like mesopelagic cephalopods and deepsea fish. In this way, the over-fishing that has been characterising the Greek seas over the last years has not affected the sperm whale.
The main threats to the populations of the sperm whale are the sea pollution as well as collisions with ships.












Sighting of a sperm whale pod west of Samos (you can see in the distance mountain Kerketeas)