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The Mediterranean monk seal A. A. Karamanlidis et al.

of age (Pastor & Aguilar 2003, Aguilar et al. 2007, Salman et al. 2001, Karamanlidis et al. 2011, Pierce et al.
Dendrinos 2011). At this time, pups begin to forage on their 2011, Muñoz Cañas et al. 2012) and stable isotope analysis
own (Pastor & Aguilar 2003). (Pinela et al. 2010, Karamanlidis et al. 2014a) suggest that
monk seals feed primarily on the continental shelf along the
coast. When a fish is caught, the prey is often first eviscer-
DIVING
ated by the seal making violent sideways movements of the
Compared with other pinnipeds, little information exists on head while holding it, and then it is ingested headfirst
the diving capacities and behaviour of Mediterranean monk (Duguy & Marchessaux 1992, Anonymous 2004).
seals. Monk seal pups may enter the water already by the
first week of their life, and their diving capacity increases THREATS
gradually with age (Mursaloglu 1986, Gazo et al. 2006,
Karamanlidis et al. 2010, Dendrinos 2011). At the end of The Mediterranean monk seal is one of the most endan-
lactation, pups at Cabo Blanco are already capable of spend- gered (Anonymous 2010a) and one of the most Evolution-
ing approximately three minutes at a depth of more than arily Distinct and Globally Endangered (EDGE; Isaac et al.
10 m (Gazo et al. 2006). The maximum duration and depth 2007) mammalian species. The intensity or importance of
of diving for one lactating female at Cabo Blanco was 15 the various threats to the species may vary regionally, but a
minutes and 78 m (Gazo & Aguilar 2005); a male adult consensus of scientific opinion considers the following
reached 100 m depth (unpublished data, CBD Habitat). often interrelating factors serious threats to the species’ sur-
Diving behaviour of monk seals at Cabo Blanco, however, vival: increased human encroachment leading to destruc-
appears to be constrained by the topographic features of the tion, alteration and fragmentation of suitable monk seal
marine environment in the region, as monk seals in the habitat; continued mortality because of deliberate killing by
Mediterranean (with much deeper waters than the Cabo humans, and fisheries by-catch.
Blanco region) have been recorded to dive for longer and to Habitat deterioration, destruction, and fragmentation
considerably greater depths. Maximum dive depths for a have played and continue to play significant roles in the
rehabilitated male and a female juvenile monk seal in plight of the Mediterranean monk seal. Once an open beach
Greece were 196 m (Dendrinos et al. 2007a) and 205 m dweller, the species has been heavily persecuted by humans
(unpublished data, MOm), respectively. While foraging, and forced to occupy inaccessible marine caves. The gradual
monk seals in Madeira and Turkey have been recorded to process from occupying open beaches to being displaced
dive for on average five to seven minutes (Neves 1998, Kiraç and forced into increasingly marginal habitat has been thor-
et al. 2002); the longest dive recorded was 18 minutes (Kiraç oughly documented (Johnson & Lavigne 1999b, González
et al. 2002). Monk seals in Greece have been recorded to 2015). Occupation of such habitat is considered to be the
travel long distances, for example ∼288 km in three months, driving force behind the low pup survival rates that have
with a maximum straight distance travelled of ∼78 km been recorded in some pupping areas (Gazo et al. 1999,
(Adamantopoulou et al. 2011). 2000b, Gücü et al. 2004). Newborn pups may be washed
away by waves surging into the caves, and may either drown
or be separated from their mothers, subsequently dying
FEEDING
from starvation (Neves & Pires 2001). Habitat deterioration
Mediterranean monk seals have often been described as is an ongoing threat, particularly in parts of the eastern
opportunistic predators (Marchessaux & Duguy 1977, Mediterranean, such as Turkey, where monk seals have been
Boutiba & Abdelghani 1997) because of their ability to observed to occupy marine caves without an internal beach
exploit various food resources easily. Studies throughout the or haul-out area so that they must rest while floating in the
monk seal’s range have revealed that the species has a het- water, and where declines in pupping success have been
erogeneous diet consisting of bony fish (mainly from the recorded (Güçlüsoy & Savas¸ 2003a, Anonymous 2007b,
family Sparidae), cephalopods (the common octopus Gücü et al. 2009a, Notarbartolo di Sciara et al. 2009, Kiraç
Octopus vulgaris is the most frequent prey item), and crusta- et al. 2013). In these areas, critical monk seal habitat has
ceans (Marchessaux 1989, Neves 1998, Salman et al. 2001, been also affected by increased tourism activities (Johnson
Karamanlidis et al. 2011, Pierce et al. 2011, Muñoz Cañas & Lavigne 1999b). It has been suggested that the marginal
et al. 2012). In Greece, more than 530 prey species have cave habitat currently occupied by the monk seal might not
been found in the stomachs of deceased monk seals (Pierce be suitable for the survival of the species, and that recovery
et al. 2011); at the island of Zakynthos monk seals have of the Mediterranean monk seal will require a partial return
been recorded preying on loggerhead turtles Caretta caretta to open beaches (Sergeant et al. 1978).
(Margaritoulis et al. 1996). Collectively, results from One of the most important threats to the survival of the
stomach contents analysis (Marchessaux 1989, Neves 1998, species, deliberate killing, is an illegal act usually committed

6 Mammal Review (2015) © 2015 The Mammal Society and John Wiley & Sons Ltd