The Mediterranean monk seal (Monachus monachus) is the rarest species of marine mammal in Europe with only around 500 individuals surviving in the world. They are currently listed as “endangered” on the IUCN (International Union for Conservation of Nature) Red List. With such a small remaining population, the actions for their monitoring and conservation are considered of high priority.
The Archipelagos Marine Mammal Team has been observing the behaviour of these seals around the North Aegean waters and logging sightings both from survey teams and from calls made by the general public. Currently, the focus with data collection is on the behaviour and local migrations. These observations last for several hours, or until the seal leaves the area. Whilst there has been some research conducted on the behaviour of M. monachus, their low numbers and relatively reclusive nature makes them a difficult species to study unless you have an area where they are known to visit.
One interesting behaviour which we are frequently observing during seal sightings is feeding. Previous studies have shown that the Mediterranean monk seal lives primarily on a diet of octopus and squid (cephalopods), with these making up over 90% of their diet (they actually rarely eat fish, preferring a meal of mollusc). When feeding the seal makes many repeated dives lasting several minutes, resurfacing to breath and have a quick rest (usually around 30-40 seconds) before diving back down to search for prey hiding on the seabed. This is continued until they catch a meal. The diving behaviour of M. Monachus has rarely been studied in general, and as such the dives made by feeding are the main data being collected, and this make this research of great importance. Time spent diving and on the surface whilst feeding can also tell a lot about the seal’s health. With consistent and regular dives being indicative of a happy and healthy seal.
Photographing the seal is also a key task when one is sighted. In this way, hopefully during the survey the Marine Mammal Team will be able to identify the seals and to tell if an individual is visiting a site repeatedly or whether that site is frequented by different seals. Snappy reflexes and a keen set of eyes are required for taking pictures of a seal in the water if it is feeding, due to the short time they surface. Other behaviours such as logging (where the seal just floats in a horizontal position in the water) and hauling out (where the seal moves onto land, often to rest) are easier to take pictures of, and when hauled out it is possible to observe and photograph identifying features.
Hopefully careful monitoring and data collection of this still relatively enigmatic animal can lead to well-prepared conservation efforts which will be key in sealing a positive outcome for the monk seal in the Mediterranean Sea.
Dan Clarke – University of Plymouth
