Monachus monachus

Monachus monachus

The Mediterranean monk seal (Monachus monachus Hermann, 1779) is a pinniped mammal belonging to the Phocidae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Animalia,
Phylum Chordata,
Mammalia class,
Order Carnivora,
Superfamily Pinnipedia,
family Phocidae,
Subfamily Monachinae,
Genus Monachus,
M. monachus species.
The term is basinym:
– Phoca monachus Hermann, 1779.
The terms are synonymous:
– Heliophoca atlantica Gray, 1854;
– Leptonyx monachus (Hermann, 1779);
– Monachus albiventer (Boddaert, 1785);
– Monachus atlantica (Gray, 1854);
– Monachus bicolor (Shaw, 1800);
– Monachus hermannii (Lesson, 1828);
– Monachus leucogaster (Péron & Lesueur, 1816);
– Monachus mediterraneus Nilsson, 1838;
– Pelagocyon monachus (Hermann, 1779);
– Phoca albiventer Boddaert, 1785;
– Phoca bicolor Shaw, 1800;
– Phoca hermannii Lesson, 1828;
– Phoca isidorei Lesson, 1843;
– Phoca leucogaster Péron & Lesueur, 1816.

Geographic Distribution and Habitat –
The Monachus monachus is a mammal with a strong decline in population which was once found throughout the Mediterranean, the Black Sea, the Atlantic coasts of Spain and Portugal, Morocco, Mauritania, Madeira and the Canary Islands, up to reports often also on the southern coast of France.
Unfortunately, during the 1900s, the range greatly reduced due to direct persecutions, so much so that this mammal survives in a few isolated colonies in Greece, in the islands of southern Croatia, in Turkey, in the archipelago of Madeira, in Morocco and Mauritania. Individuals are occasionally sighted in dispersal along the coasts of almost all Mediterranean countries.
In Italy it is considered extinct with the exception of rare sightings of specimens from North Africa or, for the Adriatic, from Croatia. Only in Sardinia, mainly in the Gulf of Orosei, there is a small nucleus that has been sighted from time to time.
Other sporadic sightings have taken place on the island of Giglio, while more irregular ones have been much further south, west of Sicily, in the Egadi Islands and in the islands of the Sicilian Channel.
A recent study based on the analysis of environmental DNA has made it possible to redraw the map of the presence of the monk seal in the central Mediterranean, identifying six areas of greatest interest: Upper Adriatic between Istria and the Venice lagoon, Salento – Gulf of Taranto, smaller Sicilian islands , Eastern Sardinia-Canyon of Caprera, Tuscan Archipelago and Balearic archipelago.
As far as its habitat is concerned, this mammal spends most of its life in the sea, however, like all phocids, it needs to stop on land to perform specific functions, such as moulting, resting, giving birth and puppy feeding. The terrestrial coastal habitat is mainly made up of sea caves with mid-infralittoral openings, with an internal emerged area well protected from wave motion. For this reason, most of the sightings recently recorded in Italy are located near isolated, rocky, high coasts, often near caves accessible only from the sea (E. Dupré in Spagnesi & Toso 1999). The use of sea caves is believed to be an adaptation of the species to protect itself from hunting to which it has been subjected over time. However, the experiences gained in conditions of complete absence of disturbance, where human access is forbidden or limited, indicate that in such conditions the species also frequents the beaches to rest and look after its offspring. The maximum diving depth known for the species is 120m, while it is known that it is able to move over maximum distances of about 280 km (Adamantopolou et al. 2011).

Description –
The Monachus monachus is a seal that has an elongated, irregularly cylindrical body, covered by a thick layer of fat, covered by a thick short hair, with slight sexual dimorphism.
This species has a length ranging from 80 cm at birth up to 240 cm in adult specimens, being able to reach 320 kg in weight; females are a little smaller than males.
Its fur is black in the male or brown or dark gray in the female, with a lighter shade on the belly, until it becomes whitish in the male specimens.
The limbs are transformed into flippers, the front ones are equipped with nails while the rear ones are almost completely devoid of them.
The head is round and slightly flattened, with ears without auricles. The muzzle is equipped with some long and robust mustaches, called vibrissae.

Biology –
The Monachus monachus is a seal that essentially lives in the sea.
In the breeding season, it prefers stretches of sea close to the coast, where it looks for isolated beaches, settling mainly in caves or small ravines accessible only from the sea, because birthing and breastfeeding take place exclusively on land.
Adult males have strongly territorial characteristics.
During the reproductive period which generally coincides with the autumn months, they frequently collide with other males.
Females reach sexual maturity when 3-5 years old, have a reproduction cycle of about 12 months and usually give birth between September and October; they nurse, in caves very close to the sea or in sheltered beaches, one cub a year, 88–103 cm long and weighing 16–18 kg.
The juveniles enter the water just a few days after birth. They are nursed up to the twelfth week, but the female leaves her cub unattended already after the first weeks of life, to return to breastfeed him periodically. The young tend to abandon the original group and to disperse even far from the place of birth; they reach sexual maturity around the age of 4.
The monk seal lives 20 to 30 years.

Ecological Role –
The Monachus monachus could descend from the Etruscan Pliophoca. This hypothesis is supported by some fossil discoveries made in Tuscany, in Pliocene clays, as this ancestor lived in the sea surrounding the Tuscan Archipelago.
Today this seal is now reduced to a few hundred specimens.
According to an estimate by the International Union for Conservation of Nature, the monk seal has a population of just 600-700 specimens: about 200 concentrated in the Aegean and in the south-eastern Mediterranean, 20-30 in the Ionian Sea, 10-20 in the Adriatic Sea, about ten in the central Mediterranean, from 10 to 20 in the western Mediterranean and less than 300 in the Atlantic. The species is therefore to be considered in danger of extinction.
However, there is no information regarding the actual presence of a population, but the reconnaissance of the sightings that occurred from 1998 to 2010 includes 84 reports, of which 51 validated and concerning 38 separate events. Estimates of the size of the specimens observed during the sightings, as well as the analysis of the photographic documentation available indicate that the sightings include both juvenile and sub-adult/adult size specimens. The sighted specimens could be individuals originating from colonies located in neighboring countries of Italy and in the dispersion phase or belonging to the remains of colonies once resident in Italian localities. We cannot exclude the attendance of other specimens in remote and less accessible places in the country (Mo 2011).
These pinnipeds also move some tens of kilometers a day in search of food, with continuous dives; dives up to 90 meters deep have been recorded, but it is probable that they can easily exceed a few hundred meters of depth, during dives carried out to search for preys.
The diet is based on cephalopod molluscs, crustaceans and fish, both benthic such as: moray eels, croakers, groupers, dentex and mostella and pelagics caught in the high seas.
It sleeps on the surface in the open sea or using small crevices on the seabed, and then periodically goes back up to breathe.
Even during stops on land, the seal remains very close to the sea, also because its movements are slow and awkward.
Unfortunately, the very strong decrease of the populations, mainly due to human intervention, has reduced these mammals to small family groups and isolated individuals. The only place in the world where the species is present in sufficient numbers to still form a colony is Cabo Blanco, in Mauritania.
In Italy, the species is particularly protected under the law of 11 February 1992.
The species is included in Annexes II and IV of the Habitats Directive, in Annex II of the SPA/BIO Protocol of the Barcelona Convention, in Annex II of the Bern Convention and in Annex I and II of the Bonn Convention. The species is included in the CITES Convention.
The IUCN Red List (2013) inserts this species among the one in serious risk of extinction: Critically endangered.
There are many reasons for the decline in populations. For example, above all in the past, it was captured to be exhibited in public and, unlike the common one, it was much more tameable. In December 1766 a specimen was captured in the waters of the Capraia and brought to the Grand Duke Pietro Leopoldo. Unfortunately it survived only up to the gates of Florence. On May 9, 1767, a specimen of about 85 cm was caught near the shallows of Meloria by some fishermen while it was resting on the wreck of a Swedish boat. Hermann described the species in 1778, when a Venetian troop, which exhibited in public a seal captured with nets in the autumn of 1777 on the island of Cherso, arrived in Strasbourg. Buffon, a famous naturalist, found another seal in Paris, again from Cherso, and, ignoring Hermann’s discovery, classified it on his behalf as Phoque a ventre blanc or Phoca albiventer. Evidently Cres became the locus classicus of the species, thanks to a well-orchestrated Venetian capture campaign.
The main pressures and threats are the retaliation of fishermen against the species (which preys in their nets), accidental catches (F02), pollution of marine waters (H03) with the consequent harmful effects deriving from the accumulation of pollutants in the tissues. Finally, the increase in human settlements (E01) and nautical traffic (along the coasts) have reduced the areas suitable for reproduction.

Guido Bissanti

Fonti
– Wikipedia, l’enciclopedia libera.
– GBIF, la Facilidad Global de Información sobre Biodiversidad.
– Gordon Corbet, Denys Ovenden, 2012. Guida dei mammiferi d’Europa. Franco Muzzio Editore.
– John Woodward, Kim Dennis-Bryan, 2018. La grande enciclopedia degli animali. Gribaudo Editore.

Photo source:
– https://observation.org/photos/12351465.jpg
– https://upload.wikimedia.org/wikipedia/commons/d/d6/A_monk_seal_%28phoca_monachus%29_sitting_on_a_rock_on_the_sea_sh_Wellcome_V0020768.jpg