It is present in parts of the Mediterranean Sea and the eastern Atlantic Ocean waters around the Tropic of Cancer, as well.
This species of monk seal grows from approximately 80 cm long at birth up to an average of 2.4 m (7.95 ft) as adults. Males weigh an average of 315 kg (695 lbs) and females weigh 300 kg (660 lbs)), overall weigh ranging from 240 to 400 kg (530–880 lbs). They are thought to live up to 45 years old; the average life span is thought to be 20 to 25 years old and reproductive maturity is reached at around age four.
The monk seals' pups are about a meter long and weigh around 15–18 kilograms, their skin being covered by 1–1.5 centimeter-long, dark brown to black hair. On their bellies, there is a white stripe, which differs in color between the two sexes. This hair is replaced after six to eight weeks by the usual short hair adults carry.
Pregnant Mediterranean monk seals typically use inaccessible undersea caves while giving birth, though historical descriptions show they used open beaches until the 18th century. There are eight pairs of teeth in both jaws. Believed to have the shortest hair of any pinniped, the Mediterranean monk seal fur is black (males) or brown to dark grey (females), with a paler belly, which is close to white in males. The snout is short broad and flat, with very pronounced, long nostrils that face upward, unlike their Hawaiian relative, which tend to have more forward nostrils. The flippers are relatively short, with small slender claws. Monk seals have two pairs of retractable abdominal teats, unlike most other pinnipeds.
Very little is known of this seal's reproduction. Scientists have suggested they are polygynous, with males being very territorial where they mate with females. Although there is no breeding season, since births take place year round, there is a peak in October and November. This is also the time when caves are prone to wash out due to high surf or storm surge, which causes high mortality rates among monk seal pups, especially at the key Cabo Blanco colony. According to the IUCN species factsheet, "pup survival is low; just under 50% survive their first two months to the onset of their moult, and most mortalities occurred in the first two weeks. Survival of pups born from September to January is 29%. This very low survival rate is associated with mortality caused by severe storms, and high swells and tides, but impoverished genetic variability and inbreeding may also be involved. Pups born during the rest of the year had a survival rate of 71%".
In 2008, lactation was reported in an open beach, the first such record since 1945, which could suggest the seal could begin feeling increasingly safe to return to open beaches for breeding purposes in Cabo Blanco.
Pups make first contact with the water two weeks after their birth, and are weaned at around 18 weeks of age; females caring for pups will go off to feed for an average of nine hours. Most individuals are believed to reach maturity at four years of age. The gestation period lasts close to a year. However, it is believed to be common among monk seals of the Cabo Blanco colony to have a gestation period lasting slightly longer than a year.
Mediterranean monk seals are diurnal and feed on a variety of fish and mollusks, primarily octopus, squid, and eels, up to 3 kg per day. They are known to forage mostly at depths of 150–230 feet, but (as a species) have been observed by the NOAA in a submersible at a known feeding ground at a depth of 500m. Monk seals prefer hunting in wide-open spaces, enabling them to use their speed more effectively. They are successful bottom-feeding hunters, and have been observed (as a species) lifting slabs of rock in search of prey.
The habitat of this pinniped has changed over the years. In ancient times, and up until the 20th century, Mediterranean monk seals had been known to congregate, give birth, and seek refuge on open beaches. In more recent times, they have left their former habitat and now only use sea caves for such things; and more often than not, these caves are rather inaccessible to humans due to underwater entries, and because the caves are often positioned along remote or rugged coastlines.
Scientists have confirmed this is a recent adaptation, most likely due to the rapid increase in human population, tourism, and industry, which have caused the destruction of animals' habitat. Because of these seals' shy nature and sensitivity to human disturbance, they have slowly adapted to try to avoid contact with humans completely within the last century, and, perhaps, even earlier. The coastal caves are, however, dangerous for newborns, and are causes of major mortality among pups.
This earless seal's former range extended throughout the Northwest Atlantic Africa, Mediterranean and Black Sea, coastlines, including all offshore islands of the Mediterranean, and into the Atlantic and its islands: Canary, Madeira, Ilhas desertas, Porto Santo... as far west as the Azores. Vagrants could be found as far south as Gambia and the Cape Verde islands, and as far north as continental Portugal and Atlantic France.
Several causes have provoked a dramatic population decrease over time: on one hand, commercial hunting (especially during the Roman Empire and Middle Ages) and, during the 20th century, eradication by fishermen, who used to consider it a pest due to the damage the seal causes to fishing nets when it preys on fish caught in them; and, on the other hand, coastal urbanization and pollution.
The species has gone extinct in the Sea of Marmara due to pollution and heavy ship traffic from the Dardanelles and the Bosporus. In addition, the last report of a seal in the Black Sea dates to the late 1990s.
Nowadays, its entire population is estimated to be less than 600 individuals scattered throughout a wide distribution range, which qualifies this species as Critically Endangered. Its current very sparse population is one more serious threat to the species, as it only has two key sites which can be deemed viable. One is the Aegean Sea (250–300 in Greece and some 100 in Turkey) and the other is the Western Saharan portion of Cabo Blanco (some 130 individuals which may support the small, but growing, nucleus in the Desertas Islands –approximately 20 individuals).
These two key sites are virtually in the extreme opposites of the species' distribution range, which makes natural population interchange between these two key sites impossible. All the other remaining subpopulations are composed of less than 50 mature individuals, many of them being only loose groups of extremely reduced size – often less than 5 individuals.
These other remaining populations are in Madeira, with 30 to 35 individuals, and the Desertas Islands (both in the Atlantic Ocean) and southwestern Turkey and the Ionian Sea (both in the eastern Mediterranean). The species status is virtually moribund in the western Mediterranean, which still holds tiny Moroccan and Algerian populations, associated with rare sightings of vagrants in the Balearic Islands, Sardinia, and other western Mediterranean locations.
Cabo Blanco 1997 die off
Cabo Blanco, in the Atlantic Ocean, is the largest surviving single population of the species, and the only remaining site which still seems to preserve a colony structure. In the summer of 1997, two-thirds of its seal population were wiped out within two months, extremely compromising the species' viable population. While opinions on the precise causes of this epidemic remain divided (the most likely cause being a morbilivirus or, more likely, a toxic algae bloom,) the mass die-off emphasized the precarious status of a species already regarded as critically endangered throughout its range.
While still far below the early 1997 count, numbers in this all-important location have started a slow-paced recovery ever since. Currently, the population in this location is estimated at 150 individuals, down from some 310 in 1997, but still the largest single colony by far. The threat of a similar incident that could wipe out the entire population remains.
Damage inflicted upon fishermen's nets and rare attacks on off-shore fish farms in Turkey and Greece are known to have pushed local people towards hunting the Mediterranean monk seal, but mostly out of revenge, rather than population control. Preservation efforts have been put forth by civic organizations, foundations, and universities in both countries since as early as the 1970s. For the past 10 years, many groups have carried out missions to educate locals on damage control and species preservation. Reports of positive results of such efforts exist throughout the area.
In the Aegean Sea, only Greece has allocated a large area for the preservation of the Mediterranean monk seal and its habitat. The Greek Alonissos Marine Park, that extends around the Northern Sporades islands, is the main action ground of the Greek MOm organisation. MOm is greatly involved in raising awareness in the general public, fundraising for the helping of the monk seal preservation cause, in Greece and wherever needed. Greece is currently investigating the possibility of declaring another monk seal breeding site as a national park, and also has integrated some sites in the NATURA 2000 protection scheme. The legislation in Greece is very strict towards seal hunting, and in general, the public is very much aware and supportive of the effort for the preservation of the Mediterranean monk seal.
The complex politics concerning the covert opposition of the Greek government towards the protection to the monk seals in the eastern Aegean in the late 1970s is described in a book by William Johnson. Oil companies apparently may have been using the Monk Seal Sanctuary project as a stalking horse to encourage greater cooperation between the Greek and Turkish governments as a preliminary to pushing for oil extraction rights in a geopolitically unstable area. According to Johnson, the Greek secret service, the YPEA, were against such moves and sabotaged the project to the detriment both of the seals and conservationists, who, unaware of such covert motivations, sought only to protect the species and its habitat.
One of the largest groups among the foundations concentrating their efforts towards the preservation of the Mediterranean monk seal is the Mediterranean Seal Research Group (Turkish: Akdeniz Foklarını Araştırma Grubu) operating under the Underwater Research Foundation (Turkish: Sualtı Araştırmaları Derneği) in Turkey (also known as SAD-AFAG). The group has taken initiative in joint preservation efforts together with the Foça municipal officials, as well as phone, fax, and email hotlines for sightings.
Preservation of the species requires both the preservation of land and sea, due to the need for terrestrial haul-out sites and caves or caverns for the animal to rest and reproduce. Even though responsible scuba diving instructors hesitate to make trips to known seal caves, the rumor of a seal sighting quickly becomes a tourist attraction for many. Irresponsible scuba diving trips scare the seals away from caves which could become habitation for the species.
In June 2009, there was a report of a sighting off the island of Giglio, in Italy. On 7 January 2010, fishermen spotted an injured Mediterranean monk seal off the coasts of Tel Aviv, Israel. When zoo veterinarians arrived to help the seal, it had slipped back into the waters. Members of the Israel Marine Mammal Research and Assistance Center arrived at the scene and tried to locate the injured mammal, but with no success. This was the first sighting of the species in the region since Lebanese authorities claimed to have found a population of 10–20 other seals on their coasts 70 years earlier. In addition, the seal was also sighted a couple of weeks later in the northern kibbutz of Rosh Hanikra.
In April 2010, there was a report of a sighting off the island of Marettimo, in the Egadi Islands off the coast of Italy, near the Province of Trapani.
In November 2010, a Mediterranean monk seal, supposedly aged between 10 and 20, has been spotted in Bodrum, Turkey.
On December 31, 2010, the BBC Earth news reported that the MOm Hellenic Society had located a new colony of seals on a remote beach in the Aegean Sea. The exact location was not communicated so as to keep the site protected. The society was appealing to the Greek government to integrate the part of the island on which the seals live into a marine protected area.
On March 8, 2011, the BBC Earth news reported that a pup seal had been spotted on 7 February while monitoring a seal colony on an island in the southwestern Aegean Sea. Soon after, it showed signs of weakness and it was taken to a rehabilitation centre to try to save it. The aim is to release it back into the wild as soon as it is strong enough.
On June 24, 2011, the Blue World Institute of Croatia filmed an adult female underwater in the northern Adriatic, off the island of Cres and a specimen of unverified sex on June 29, 2012.