Mediterranean Monk Seal
(Monachus monachus)

This page is currently (August 2011) being updated

IUCN STATUS (2010) CRITICALLY ENDANGERED

Distribution and Numbers

The Mediterranean monk seal is the most endangered pinniped species worldwide and is currently on the brink of extinction. Although formerly found all over the Mediterranean Sea, Black Sea and northwest African coast, the species' numbers have now been reduced to perhaps less than 600. Whereas the former distribution was continuous throughout its range, the present distribution is discontinuous, with probably little exhange between the separated populations (Johnson et al., 2006). The remaining seals are found in remote and undisturbed areas around the north-east Mediterranean Sea (Greece and Turkey) and northwest African coast (Mauritania), with a few individuals along the Mediterranean coast of Morocco and the Portuguese Desertas Islands of Madeira (Johnson et al., 2006).

Monachus monachus - Image 1

Photo: Matthias Schnellmann,
The Monachus Guardian

Status

For centuries Mediterranean monk seals have been killed by fishermen who see the seals as competitors or accuse them of destroying their fishing gear. In the past the seals were also killed by those who believed that sealskin and seal parts were able to provide protection from a variety of medical problems. When European explorers discovered the monk seal colonies off the NW coast of Africa, they made short work of them to lucrative advantage. In the Mediterranean, sustained persecution coupled with disturbance and habitat degradation appears to have suppressed colony formation and led to fragmentation of relict populations. A 'naturally gregarious and beach-dwelling species' became transformed into 'a less social and reclusive inhabiter of caves' (Johnson et al., 2006). The final demise of the monk seal in the Black Sea may have been accelerated by the repeated capture of individuals for zoos and outdoor fairs in the 1970s (Öztürk, 1993). The mortality of monk seals by entanglement in fishing gear is still a problem, while over-fishing has also resulted in a general lack of food resources. The continually increasing use of motor vessels, expansion of fishing effort and areas, coastal construction and increased tourism have all contributed to difficulty in protecting monk seal habitat and preventing recovery of monk seal colonies.

The colony of monk seals on the Cap Blanc peninsula in Mauritania, NW Africa numbered ~270 individuals, incuding ~50% adults and 50% subadults, juveniles and pups (Jiddou et al., 1997). It was therefore the largest surviving population of Mediterranean monk seals by the mid 1990s and the only one to possess the actual social and numerical structure of a colony. However, in May-June 1997 there was a mass mortality of seals at this important colony. The mortality was first noted on May 05, and ended ~02 June. 47% of the population died, including 74% of adults. An initial diagnosis based on 4 of 17 of the dead seals and from blood samples taken from five live seals suggested the presence of a morbillivirus infection, probably from a small cetacean carrier (Osterhaus et al., 1997). However, there was also strong evidence for a toxic algae bloom in the Cape Blanc region at this time, and the dead seals were exposed to this, and the conclusion was that the algae bloom was probably the main cause of the mortality (Harwood et al., 1998). Fortunately the colony is now recovering, and believed to number about 200 individuals as of 2011 (Monachus Guardian, personal comunication).

Four pups whose mothers were presumed to have died durng the 1997 mortality were taken from caves on May 24–25, rehabilitated and released again, fitted with satellite tags, on September 20 and December 23 (Jiddou et al., 1997). They were apparently released some distance from the colony. The signal from one of the first two pups was lost after two days, while the other pup did not return to the coony but remained some 50 km suth of the release point (Harwood et al., 1998). The development of a protocol for rescue, rehabilitation and release of monk seals, in conjunction with the IUCN Re-introduction Specialist Group, was therefore recommended (Harwood et al., 1998).

The species is listed as Critically Endangered on the IUCN Red List (Aguilar and Lowry, 2008) and as an Appendix I species under CITES. It is also listed as an Appendix II species under the Bern Convention, as an Appendix I and Appendix II species under the Bonn Convention, and as an Annex II and Annex IV species under the European Community's Habitats Directive. In Greece the Meditereanean monk seal was given complete protection in law in 1981, and a Strategy for the protection of the monk seal in Greece was published by Mom (the Hellenic Socity for the study and protection of the monk seal) in 1996 and revised in 2009.

Monachus monachus - Image 2

Pup - photo : Cem O. Kiraç, SAD-AFAG

Mm pup image Dendrinos

Pup - Photo: Alexandros Karamanlidis, MOm

Monachus monachus - Image 3

Photo : Cem O. Kiraç, SAD-AFAG

Various protected areas have been created by diferent countries with the aim of protecting the Mediterranean monk seal within its present limited range. The difficulty of creating protected areas with boundaries is that the present distribution of monk seals is highly fragmented and discontinuous, and a protected area should be large enough to contain a Minimum Viable Population (MVP) (Durant and Harwood, 1992). To date, Marine Protected Areas for monk seals have been established at the Desertas Islands in Madeira, the National Marine Park of Alonnissos Northern Sporades in Greece, on the Aegean (at Foça and Yalikavak) and the Mediterranean cost of Turkey, and along the Côte des Phoques (Cap Blanc) in Mauritania/Western Sahara. In addition, Special Areas of Conservation (SACs) under the EU Habitats Directive have been proposed to initiate a wider network of protected areas. Conservation measures within each of these protected areas differ according to national laws and programmes (e.g. Wilson et al., 2001). Along the Turkish Mediterranean coast the establishent of several no-fishing zones has reduced entanglement and thus improved pup survival (Johnson et al., 2006). In March 2001, Mauritania announced a ban on all fishing, except traditional non-motorised fishing by local communities, along the Cap Blanc coast, and also strict protection of the caves used by the colony and surrounding beaches. Until then, the beaches had only been used by a few adult males.Since 2006 the beaches have been used by all classes of seals, including mothers and pups, and this important population is now believed to be recovering from its low point following the 1997 mortality. Nevertheless, the practices of artisanal fishermen continue to pose a threat to the seals (Johnson et al., 2006; Monachus Guardian, 2007, and seals are still being deliberately shot by fishermen, especially in parts of the Greek Aegean sea. Because the relict populations in each of the protected areas is so small, and probably well below the MVP, the potential survival of the population will depend heavily on variation in the inherent properties of individuals, eg fecundity, foraging ability, behavioural adaptibility etc, and also on environmental factors, including disease outbreaks, pollution events or hunting/fishing mortality (Durant and Harwood, 1992).

A computer simulation study of the extinction risks for monk seals suggests that population size within a reserve should be monitored by means of analysis of the number of sightings of identifiable animals, which should be observed directly on beaches or by using 'camera traps' placed at resting sites, including cave entrances (Durant and Harwod, 1992). Where there is a predictor of extinction (these are defined for small populatons of different sizes, and include measures such as zero pups born, low % of breeding adults, low % juveniles observed in a population), then every effort should be made to increase both juvenile and adult survival. Juvenile survival may be increased by rescue of abandoned pups and of seals entangled in fishing gear (Durant and Harwood, 1992).  

 

Life history
Mediterranean monk seal pups are generally born in September and October in a black or chocolate-brown lanugo coat with a creamy-white patch on their belly. The variation in the features of this patch, which frequently has black spots, allows non-invasive individual and gender identification of pups (Badosa et al., 1998). The pups moult from about 8 weeks of age (64 days in females, 82 days in males), its black coat replaced by a silvery dark-grey coat (Badosa et al., 2006). The adult coat varies but is generally a smooth dark brown dorsally. The name originated from an observation by J. Hermann (author of the first scientific description of the species in 1779), who wryly likened the shape of the head and shoulders of the seal when hauling out to a monk's habit. During the annual moult throughout life, sheets of epidermis are shed along with the hair, and the shedding period lasts about 15 days (Badosa et al., 2006).

Pups are nursed for a period now known to be about four months - a study of 9 pups at Cap Blanc found lactation lasted 103–149 days (Pastor and Aguilar, 2003; Aguilar et al., 2007), which is almost twice as long as any other phocid seal, and more than twice as long as the 5–6 week lactation of the Hawaiian monk seal. Pups sometimes suckle from females other than their mothers, and fostering - long term or short term -may sometimes occur (Aguilar et al., 2007). After the first week, the mothers of two pairs observed, along with a few other seals, in a Turkish cave (Mursaloglu, 1986) left the pup for some hours at a time to go fishing. When the mother was away, the pup mostly slept, and if hungry, would start to bleat, eventually producing a wailing cry if the mother did not soon return. Mother and pup communicated vocally and by close physical contact when reunited (Mursaloglu, 1986). While the mother was away, the pup was often washed to and fro by the sea flooding the cave, and the pup often responded by curling into an 'egg' shape, thus floating passively for some hours. The pup also learned to swim in quiet water, gradually gaining sufficient motor control. The pup showed no interest in fish swimming in the waters of the cave. About two months after moulting, the pup followed its mother out of the cave. Soon after the pup moulted, all the seals deserted the cave, including the mother and pup (Mursaloglu, 1986). More recent observations of a cave containing a mother-pup pair, three other adult females and a juvenile were achieved using a surveillance infrared camera system (Dendrinos et al., 2007). The mother and pup always occupied one section of the beach, while the other seals occupied the other section; the juvenile twice tried to approach the newborn pup, but was aggressively repelled by the mother. The surveillance system also recorded the date and hour of each seal's entry and exit to and from the cave. Using this monitoring system, two births were recorded in the cave in 2007 (Karamandilis et al., 2010). In both cases the birth was immediately followed by a period of intense nuzzling and vocalisations. The pup remained in close body contact for ~5h after birth before moving ~1adult body length away. The first suckling occurred ~6hr post-partum, and thereafter about every 4h for the next 4–5 days, after which the mother left the pup for the first time. A storm occurred when the pup was two days old, and the mother manoeuvred it back to the beach and placed herself between the pup and the waves.  The 2nd mother simlarly stayed with her pup for 4–5 days before leaving it for the first time. In a study in Madeira, a mother was observed to protect a neighbouring pup from being swept away by the waves while its own mother was away fishing (Pires, 2004).The 2nd mother in the Greek study was scared away by a human intruder into the cave and did not return for 7h. The authors point out that the disturbance might have led to permanent separation and death of the pup (although in this case mother and pup were successfully reunited). Effective protection of pupping sites against disturbance is considered to be one of the outstanding conservation prioriities for the monk seal.

The principal mating season of the Mediterranean monk seal is from October to November. At Cap Blanc, several adult males display underwater territorial behaviour, with the apparent aim of gaining and maintaining access to females (Johnson et al., 2006).

Studies of diving, both by means of time depth recorders (TDRs) attached to the seals' backs and by direct observation, have identified two distinct types of dives, i.e. 'spot feeding dives' where the seal dives continuously, perhaps for several hours, in the same spot, and 'transit feeding dives' where the seals cover some distance along the shoreline (Kiraç et al., 2002). Monk seal dives recorded have been relatively shallow, with most dives of one adult male being <8m and only 5% exceeding 50m (Gazo, 1997). Pups develop their divng capacity while still nursing, but increase their diving activity after weaning. Nearly half the dives of newly weaned pups were U-shaped, with a mean depth of 11m, maximum depth of just over 20m and mean duration 150s. The long bottom times (mean 100s) suggested the pups were feeding. Older pups had a higher proportion of u-shaped dives in deeper water up to 40m (Gazo et al, 2006). One rehabilitated female pup (Artemis) aged about 5 months was recorded diving to 117m (Monachus Guardian 2009) while a male rehabilitated pup (Dimitris) was recorded diving to 180m (Monachus Guardian 2004). However, these were maximum dives, and the diving behaviour of rehabilitated pups may not be typical of the species.

Mediterranean monk seals are opportunistic feeders, mainly foraging close to the shore near shallow reefs. They seem to prefer bony fish such as mullet and sea bream, but also take benthic cephalopods (such as octopus) and crustaceans (such as lobster). Usually monk seals are considered to be relatively sedentary, with adult males having a home range of up to ~50km (Johnson et al., 2006). When facing a food scarcity, however, adults may travel considerable distances, 65–159nm Adamantopoulos et al., 1999), and these longer-range movements need to be considered when designing conservation measures (Wilson et al., 2001).

Vital statistics

Mediterranean monk seals are relatively large seals, with an adult nose-to-tail length of ~280cm and weighing up to about 300kg or more, with adult males being slightly larger than females (King, 1983; Johnson, et al., 2006). The breeding season is not well defined, but most pups in the current distribution range are born in the autumn (Johnson et al., 2006). Pups are born measuring 88-103cm in length and weighing ~15-20kg. Nutritional weaning age is uncertain, being given at about 6 weeks (King, 1983), which would be similar to Hawaiian monk seals. More recently it has been observed that pups may be nursed for as long as 16–17 weeks. This is much longer than in any other phocid seal (Pastor and Aguilar, 2003; Aguilar et al., 2007). Weaning weight seems not to be known. Sexual maturity is usually reached at the age of 5-6 years, and it is thought that individuals can live up to 20-30 years of age (Johnson et al., 2006).

A plan by the French government in 1990–94 to start a captive breeding project at Antibes Marineland with individuals captured from the wild failed after opposition from the scientific and conservation community (Johnson and Lavigne, 1994). Reasons include the negative impact on existing small populations of taking individuals, the stress on those seals, the poor track record of aquaria for maintaining monk seals in captivity, and no record of successful captve breeding. The possibility of relocating monk seals from Mauritania to parts of the species' former range, such as the Canary Islands or the Black Sea, or to reinforce the small Madeira population, have been considered, but not carried out because of the risks involved (Harwood et al. 1978). Rescue and rehabilitation of 'orphan' pups is considered to be a valuable conservation tool for this species because of the very low numbers of pups born and surviving to maturity and the development of a protocol for the rescue, rehablitation and release of monk seas, in conjunction with the IUCN re-introduction specialist group,was recommended Harwood et al., 1998).

Rehabilitation of orphan pups

Because of the potential importance to the species of successful rehabilitation of orphan pups, the available information on the behaviour and survival of pups after release will be gradually assembled in this section. Information on all rehabilitation efforts between 1990 and 2004 are presented in a summary paper by Mom (Hellenic Society for the study and protection of the monk seal), 2005.

Four pups whose mothers were presumed to have died durng the 1997 mortality were taken from caves on May 24–25, rehabilitated and released again, fitted with satellite tags, on September 20 and December 23 (Jiddou et al., 1997). They were apparently released some distance from the colony. The signal from one of the first two pups was lost after two days, while the other pup did not return to the colony but remained some 50 km suth of the release point. This falure was the trigger for the recommendation of a rehabilitation protocol (Harwood et al., 1998).

Since then there have been a number of pup rehabilitation instances after which the pup has been released.

The growth of six pups (Theo, Dimitris, Theodore, Stelios, Efstratia and Katerina) rehabilitated at the Alonissos centre is described by (Androukaki et al, 2002). The pups were initially tube fed on fish porridge, then fed on dead fish, first by force-feeding, then hand-feeding and then self feeding from fish thrown into a pool .

A male pup Dimitris was rescued from the Island of Karpathos in the eastern Aegean on December 29 2004. He was estimated to be about 3 weeks old, and thought to have been separated from his mother duDring a severe storm three days earlier. A news update on March 5 indicated that he was doing well in rehabilitation.  Dimitris was released on May 22, fitted wth a satellite transmitter and a time-depth recorder (TDR). Four months later he was found to be alive and well, moving around the entire Sporades national marine park area. He was twice found to be sleeping in a well-known monk seal cave in the area.

On December 5 2006 a female pup Badem was found on the Turkish Aegean coast. She was taken to Foça, where a dedicated rehabilitation centre was immediately equipped appropriately for her care. Badem was released on April 28 2007. She was not fitted with a satellite tag, but was fitted with a small plastic tag on her hind-flipper. Following her release, she was monitored daily, and found to be interacting frequently with people along the shore. Because of this, the monitoring group (SAD-AFAG) issued an information brochure asking people not to interact with her. However, despite this, after a group of students tried to pick her up she apparently bit six people. A week later, she was reported to have bitten ten people who tried to play with her. She also apparently initiated interactions with people who were not trying to interact with her, scratching some people and almost causing one man to drown. In February 2008 she was investigating the cages of a fish farm, but this problem was solved by installing a renforced outer net of the cage. On June 15 2008 a person spear-fishing threatened to harpoon her, and three gendarmes were assigned to protect her. In early July 2008 she was taken into custody until the end of the tourist season, for her own safety and that of human swimmers. She was held in a 50x50m enclosure of depth 22m within a bay on the Turkish coast. She was released again in September. From December 2008 she started to spend less tme along the shore seeking human contact and more time sleeping in inflatable boats offshore. However further raids on fish farms were reported, and in January 2009 she was found to have an eye infection apparently caused by an injury from a sharp object. Badem was again brought into the bay enclosure, with the intention of releasing her after recovery of her eye. A report dated December 2010 suggested she had been in captivity again during the summer of 2010.

In October 2008 a nursing pup with an infected eye was noted in a cave on the island of Piperi. The pup was briefly caught, long-acting antibiotic administered, and the pup's progress monitored for the next two days. The pup appeared to be otherwise healthy, and the eye was beginning to heal.

A female pup Artemis was rescued in December 2008 on the Greek Island of Leros. She was rehabilitated at the Alonissos centre, and was released, wearing a satellite transmitter with time-depth recorder, in April 2009 at Piperi Island, within the core zone of the protected area of the Marine Park of the Sporades. Sadly she died one month later, while diving to feed at ~25m in Skiathos harbour, an area lying outside the protected (fisheries exclusion) zone. The necropsy indicated that the cause of death was pulmonary oedema, suggesting that she was trapped in fishing gear. She had travelled a total of about 150km from Piperi island, migrating from Piperi island to the mainland coast, along the coast and the out to Skiathos. It is not known how this long dispersal movement would compare with post-weaning dispersal of a wild post-weaning pup born in this area.

Two pups were rescued from the Turkish Aegean coast on 18 December 2010, having apparently been separated from their mothers during a storm. The pups were cared for at the Foça centre and apparently (from photos) housed together. They were initially fed from a bowl instead of being tube fed. They were deemed to be ready for release on April 2nd 2011, having attained weights of 34 and 37kg, and their release on April 2nd, in a remote part of Turkey's monk seal habitat area, was confirmed. SCS note: We do not know the sexes and 'names' of these two pups, but the fact that they seemed to have been housed together during rehabilitation should benefit the development of their normal socialisation and enable them to integrate readily with the wild seal population rather than to seek human company. Their relatively early release should also benefit their normal behaviour development in the wild.

A pup Nereus was found stranded and apparently weak on the island of Kythira in February 2011. The pup was taken to the Alonissos centre, where he was diagnosed with a heavy internal parasite load and skin problems. He was released at Alonissos on March 19th, but without any tracking devices.

Rehabilitation means reintroduction, with external help, to the normal ways of life of the species – a return to the population (T. Schultze-Westrum, 2001). From the experience of rehabilitation over the past 10 years, it seems that some review and refinement of the rehabilitation protocol may help to achieve this aim with a greater number of monk seal orphans. Although Badem seems to have been an extreme example, monk seals do seem present several challenges to be overcome which include their natural 'tameness', their sociality and and their assertive and extrovert nature. An ideal rehabilitation procedure might be to try to mimic the natural behaviour, nutrition and the natural developmental timetable of the wild pup as closely as possible. More observational field studies of wild pups from birth to a few months of age would inform this process: studies could include the natural nursing and weaning periods, pup behaviour, social environment, interactions with mother and other seals and the development of swimming and diving behaviour. 

 

Internet links

The Monachus Guardian

Mom (Hellenic Society for the study and protection of the monk seal)

CBD Habitat monk seals

The Mediterranean monk seal research group (Turkey) (SAD-AFAG)

Watch a monk seal birth, filmed in a cave in October 2007

A monk seal pup in a cave, filmed in November 2009

A monk seal spotted on the Mani coast of Greece

Monk seal pup Badem in rehabilitation at Foça, Turkey

Rehabilitated monk seal juvenile 'Badem' interacting with divers

A beach habitat for monk seals in Greece recently discovered (December 2010)

 

References

Aguilar, A, Cappozzo, L.H., Gazo, M, Pastor, T., Forcada, J. and Grau, E. (2007).  Lactation and mother-pup behaviour in the Mediterranean monk seal Monachus monachus: an unusual pattern for a phocid. J. Mar. Biol. Ass. UK. 87: 93–99. doi:10.1017/S0025315407056147.

Aguilar, A. & Lowry, L. 2008. Monachus monachus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1. <www.iucnredlist.org>.

Androukaki, E., Fatsea, E., 't Hart, L., Osterhaus, A.D.M.E., Tounta, E. and Kotomatas, S. (2002).  Growth and development of Mediterranean monk seal pups during rehabilitation.  Poster paper presented at the 16th ECS Conference, 7–11 April 2002, Liege, Belgium.

Badosa E., Grau, E, Aparicio,F. Layna,J.F.and Cedenilla, M.A. (1998). Individual variation and sexual dimorphism of coloration in Mediterranean
monk seal pups (Monachus monachus). Marine Mammal Science 14:390-393.

Badosa, E., Pastor, T., Gazo, M. and Aguilar, A. (2006).  Moult in the Mediterranean monk seal from Cap Blanc, western Sahara.  African Zoology 41(2): 183–192

Dendrinos, P., Tounta, E., Karamanlidis, A.A., Legakis, A. and Kotomatas, S. (2007).  A video surveillance system for monitoring the endangered Mediterranean monk seal (Monachus monachus).  Aquatic Mammals 33(2): 179–184.

Durant, S.M. and Harwood, J. (1992).  Assessment of monitoring and management strategies for local populations of the Mediterranean monk seal Monachus monachus. Biol. Conserv. 61: 81–92.

Gazo, M. 1997. Diving activity data on one of the most endangered divers: an adult male Mediterranean monk seal. How to obtain the information without disturbing the diver. In: P.G.H. Evans, E.C.M. Parsons & S.L. Clark [eds.]. Proceedings of the Eleventh Annual Conference of the European Cetacean Society, Strasund, Germany, 10-12 March 1997: 302.

Gazo, M., Lydersen, C. and Aguilar, A. (2006).  Diving behaviour of Mediterranean monk seal pups during lactation and postweaning. Mar. Ecol. Prog. Ser. 308:303–309.

Harwood, J., Lavigne, D. and Reijnders, P. (1998).  Workshop on the causes and consequences of the 1997 mass mortality of Mediterranean monk seals in the western Sahara.  Amsterdam 11–14 Dec., 1997. IBN Sci. Contrib. 11. DLO Institute for Forestry and Nature Research (IBN-DLO), Wageningen, 1998. 32pp.

Jiddou, A.M., Vedder, E., Martina, B., Dedaii, S., Soueilem, M M, Diop, M, Ba, A.S. and Osterhaus, A. (1997).  Memorandum on the mass die-off of monk seals on the Cap Blanc peninsula.  CNROP/SRRC December 1997; 22pp.

Johnson, W.M. and D.M. Lavigne. 1994. Captive Breeding and the Mediterranean Monk Seal – A Focus on Antibes Marineland. International Marine Mammal Association Inc., Guelph, Canada: 1-44.

Johnson, W.J., Karamanlidis, A.A., Dendrinos, P., Larrinoa, P.F., Gazo, M., González, L.M., Güçlüsoy, H., Pires, R. and Schnellman, M. (2006). Mediterranean monk seal (Monachus monachus). Monk seal fact files.  Monachus Guardian.

Karamanlidis, Alexandros A.; Paravas, Vangelis; Trillmich, Fritz; Dendrinos, Panagiotis (2010) First Observations of Parturition and Postpartum Behavior in the Mediterranean Monk Seal (Monachus monachus) in the Eastern Mediterranean, Aquatic Mammals. 36(1): 27-32.

King, J.E. (1983).  Seals of the World, 2nd ed. British Museum (Natural History). Cornell University Press, Ithaca, N.Y.  ISBN 0-8014-1568-3. 240pp.

Kiraç, C.O., Savas, Y., Güçlüsoy, H and Veryeri, N.O. (2002).  Observations of diving behaiour of free-ranging Mediterranean monk seals Monachus monachus on Turkish coasts. The Monachus Guardian 5(1): May 2002.

MOm (2005).  Mediterranean monk seal rehabilitation in Greece 1990–2004: 15 years of action. Hellenic Society for the study and protection of the monk seal. Athens, 2005. 

Mom (2009). National strategy and action plan for the conservation of the Mediterranean monk seal in Greece, 2009–2015. Hellenic Society for the study and protection of the monk seal. Athens, 70pp.

Mursaloglu, B. (1986). Pup-mother-environment relations in the Mediterranean monk seal, Monachus monachus (Hermann 1779), on Turkish coasts.  Commun. Fac. Sci. Univ. Ank. Ser. C. 4:1–8.

Osterhaus, A., Groen, J., Niesters, H., Bildt, M. van de, Martina, B., Vedder, L. Vos, J., Egmond, H. van, Sidi, B.A. and Barham, M.E.O. (1997).  Morbillivirus in monk seal mass mortality. Nature (Lond.) 388: 838–839.

Öztürk, B. (1993).  Investigation on the distrbution of the Mediterranean monk seal Monachus monachus (Hermann, 1779) in the Black Sea. Instanbul Universiy Journal of Aquatic Products 1-2: 95–104.

Pastor, T. and Aguilar, A. (2003). Reproductive cycle of the female Mediterranean monk seal in the western Sahara. Mar. Mamm. Sci. 19: 318–330.

Pires, R. (2004).  One pup –three 'mothers'.  The Monachus Guardian 7(1): June 2004.

Wilson, S.C., Mo, G. and Sipilä, T. (2001).  Legal protection for seals in small populations in European community and Mediterranean coastal waters.  Mammalia 65(3): 335–348.