Monachus monachus
Creators: name: Russell A. Mittermeier
name: Don E. Wilson
Publisher: name: Lynx Edicions
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Carnivora
Phocidae
Monachus
Monachus monachus

description: 2.
Mediterranean Monk Seal
Monachus monachus
French: Phoque de la Méditerranée / German: Mittelmeer-Monchsrobbe / Spanish: Foca monje del Mediterraneo
Other common names: Monk Seal
Taxonomy. Phoca monachus Hermann, 1779,
“Dalmatian Sea at Ossero.” Restricted by J. E. King in 1956 to Serbia and Montenegro.
Differences in skull morphology and genetic differentiation between Atlantic and Mediterranean subpopulations of P. monachus have been described, but no taxonomic separation has been suggested to date. Monotypic.
Distribution. Mediterranean, scattered in islands in Aegean and Ionian seas and coasts of Greece and W Turkey, NE Morocco, and NW Algeria; E Atlantic Ocean at Desertas Is (Madeira Is group) and Ras Nouadhibou (= Cabo Blanco/Cap Blanc Peninsula) on the border between Western Sahara and Mauritania; occasionally recorded in Canary Is, Mauritania (Banc d’Arguin), Tunisia (La Gallite), Libya (Cyrenaic coast), and the Adriatic coast in Croatia.
Descriptive notes. Total length 230-280 cm; weight 240-300 kg. Male Mediterranean Monk Seals are slightly larger than females, 5% longer on average at the Ras Nouadhibou colony. Newborns are 80-90 cm in length and weigh 15-26 kg, and they are black with white patch on belly that appears to vary with sex. Young molt when they are c.40-100 days old and then are silvery gray dorsally and lighter ventrally and retain white belly patch throughoutlife. Juveniles and adult females are dark dorsally and lighter ventrally. Adult Mediterranean Monk Seals are sexually dimorphic in pelage color; males are black dorsally and ventrally except for whitish throat and white belly patch, and females are medium gray to dark gray with a paler hood and mask around eyes.
Habitat. Predominantly coastal, preferring secluded coastlines with sheltered beaches and caves along inaccessible rocky cliffs. To avoid terrestrial predators, Mediterranean Monk Seals use caves with sea entrances for hauling out and giving birth throughout their distribution. In the Northern Sporades Archipelago of Greece in the northwestern Aegean Sea, caves that females select to give birth can be predicted by their seclusion (distance from human disturbance), substrate of the associated beach, and degree of protection from wind and waves. Mediterranean Monk Seals appear to forage near these sites in relatively shallow waters, but they have been observed as far as c.130 km from shore. Historically, Mediterranean Monk Seals in the Atlantic Ocean also inhabited beaches ofislands and sand banks and open beaches on the mainland, where there are records of large aggregations.
Food and Feeding. The diet of Mediterranean Monk Seals is diverse and includes benthic and epibenthic fish such as those of the families Moronidae, Rhinobatidae, Sparidae, and Clupeidae; cephalopods of the genera Octopus, Sepia, and Loligo, and crustaceans such as Palinurus spp. They are opportunistic feeders exploiting the most abundant resources at the time. In the Aegean Sea off Turkey, stomach contents of two Mediterranean Monk Seals contained fives species of prey, dominated by cephalopods (94% by weight) including, most commonly, the common cuttlefish (Sepia officinalis) and, for the first time, the musky octopus (Eledone moschata) and the globose octopus (Bathypolypus sponsalis). Daily food intake has been estimated at ¢.5-10% of their total body weight. Maximum diving depth has been recorded at 90 m, but dives rarely exceed 50 m.
Breeding. Genetic studies in Ras Nouadhibou colony suggest that Mediterranean Monk Seals have a complex social structure, with a low level of polygyny as evidenced by the low relatedness among young from the same birthing season but with a remarkable temporal periodicity. In contrast, social structure in the eastern Mediterranean near Turkey appears to be one or more reproductive females selectively using the same caves within the range of control of a single adult male. Female Mediterranean Monk Seals are sexually mature at ¢.3 years of age. Birthing season is extremely protracted, and females give birth throughout the year, with small peaks in September and October. Nursing is also longer than in other species of Phocidae, lasting for c¢.16-17 weeks, with females feeding at sea during the nursing period and leaving young unattended while feeding. Sexual activity has only been observed to occur underwater. Offspring are weaned when they are about four months old, with up to five months reported. Survival of young Mediterranean Monk Seals is less than 50% during their first two months, with most mortalities occurring in their first two weeks postpartum. Maximum-recorded age is 44 years for an individual from the Aegean Sea.
Activity patterns. Behavior and activity of Mediterranean Monk Seals are not well known. At the Ras Nouadhibou colony, adult males defend territories, which are not continuous along the coastline. Small numbers of males defend aquatic territories at the entrance of breeding caves, while a larger number of males defend aquatic territories in surrounding areas not suitable for giving birth. Tenure of aquatic territories extends throughout the year and, in some cases,for several years. Females and young are regularly found only in breeding caves.
Movements, Home range and Social organization. Mediterranean Monk Seals do not appear to be migratory, although some individuals have been observed to move 30-50 km along coastlines and to offshore islands, sometimes in response to disturbance by humans. Mediterranean Monk Seals are not particularly gregarious or social, but up to 89 individuals have been seen ashore at the Ras Nouadhibou colony.
Status and Conservation. CITES Appendix I. Classified as Critically Endangered on The IUCN Red List. The Mediterranean Monk Seal has been listed as a foreign endangered species under the US Endangered Species Act since 1970. Mediterranean Monk Seals once lived throughout the Mediterranean Sea and into the south-eastern North Atlantic to the Azores, Canary Islands, and Cape Verde Islands and along the coast of Africa. They now breed at a few scattered locations on islands and some secluded mainland coastlines on beaches and in caves. Distribution of the Mediterranean Monk Seal has shrunk substantially because populations have declined markedly, and it is currently very small and highly fragmented. Mediterranean Monk Seals have been hunted for centuries for food, skins, and oil, and in more recent times, because they have been perceived to compete with fishermen for food. They have been displaced by coastal development and other human activities in the Mediterranean Sea and are a risk from entanglement with fishing nets and marine debris. Lack of genetic diversity from a severe bottleneck is apparent in Mediterranean Monk Seals in the Ras Nouadhibou colony near Mauritania in the Western Sahara. Contaminants may be a serious issue for Mediterranean Monk Seals in parts of their distribution; organochlorines in blubber of individuals in the Sahara coast population appear to be low, but one individual from the western Mediterranean had levels higher than thresholds that can cause immunosuppression and reproductive difficulties. Range-wide abundance was estimated at c¢.600-1000 individuals in the 1970s but has declined to ¢.350-450 or fewer individuals, with 150-200 individuals in Greece, 100 individuals in Turkey, only 20-23 individuals at Madeira, and c¢.130 individuals at the Western Sahara area. The most viable population along the Western Sahara coast estimated at ¢.300 individuals was reduced by ¢.60% in 1997 during a mass mortality caused by a distemper-like virus.
Bibliography. Aguilar & Lowry (2013), Alfaghi et al. (2013), Borrell et al. (1997), Dendrinos et al. (2007), Forcada et al. (1999), Francour et al. (1990), Gazo et al. (2006), Gomercic et al. (2011), Gonzalez (2013), Gonzélez & Fernandez de Larrinoa (2013), Hardwood (1998), King (1956), Pastor, Cappozzo et al. (2011), Pastor, Garza, Aguilar et al. (2007), Pastor, Garza, Allen et al. (2004), Reijnders et al. (1993), Salman et al. (2001), Samaranch & Gonzalez (2000).
description: Published as part of Russell A. Mittermeier & Don E. Wilson, 2014, Phocidae, pp. 120-183 in Handbook of the Mammals of the World – Volume 4 Sea Mammals, Barcelona :Lynx Edicions on pages 169-170, DOI: 10.5281/zenodo.6607185