|Scientific Name:||Carcharodon carcharias (Linnaeus, 1758)|
Squalus carcharias Linnaeus, 1758
|Red List Category & Criteria:||Critically Endangered A2d (Regional assessment) ver 3.1|
|Assessor(s):||Soldo, A., Bradai, M.N. & Walls, R.H.L.|
|Reviewer(s):||Dulvy, N.K. & Allen, D.J.|
Mediterranean regional assessment: Critically Endangered (CR)
The Great White Shark (Carcharodon carcharias) is a large (up to ~640 cm total length) pelagic species that occurs throughout the Mediterranean Sea, albeit in very low numbers. Little is known about its biology, though notably it has a low intrinsic rebound potential and long generation length of at least 23 years. This shark is subject to both incidental fishing mortality and persecution, not just because of human attacks but also as it has a reputation for damaging fishing gear and scavenging hooked fish. The Mediterranean Sea Great White Shark subpopulation has recently been revealed as genetically distinct from the Atlantic subpopulation. The apparent historical basis of this genetic isolation deems the Mediterranean subpopulation at significantly greater risk of local extinction than once thought. Records of the species show a declining trend since the 1970s, with a complete absence from several areas during the 1990s. There have since been several more recent records in the eastern Mediterranean Sea, mainly of juveniles.
The Great White Shark is assessed regionally as Critically Endangered under Criterion A2d based on: i) genetic isolation of the Mediterranean subpopulation; ii) the slow life history of the Great White Shark; iii) past and ongoing subpopulation decline resulting from ongoing fishing pressure; iv) the species' negative reputation and consequent ongoing persecution; and v) the declining status of all large sharks in the Mediterranean Sea owing to a lack of effective management measures. The subpopulation is suspected to have undergone a decline exceeding 80% over the past three-generation period (69 years) based on perceived disappearances from several heavily fished localities within the region.
|Range Description:||The Great White Shark has a global range throughout most seas and oceans with concentrations in temperate coastal seas (Compagno 2001), possibly a result of subtropical submergence (Ebert and Stehmann 2013). A recent study revealed that the Mediterranean Sea subpopulation is genetically distinct from the Atlantic subpopulation (Gubili et al. 2011). Within the Mediterranean Sea the Great White Shark has been found most frequently in the strait of Sicily and the Adriatic Sea (Fergusson 1996, Bradaï and Saïdi 2013) and more recently in the Aegean Sea (Kabasakal and Gedikoglu 2008, Kabasakal et al. 2009), but is believed to occur or have recently occurred throughout the basin. Its depth range is zero to >250 m.|
Native:Albania; Algeria; Bosnia and Herzegovina; Croatia; Cyprus; Egypt (Egypt (African part), Sinai); France (Corsica, France (mainland)); Gibraltar; Greece (East Aegean Is., Greece (mainland), Kriti); Israel; Italy (Italy (mainland), Sardegna, Sicilia); Lebanon; Libya; Montenegro; Morocco; Palestinian Territory, Occupied; Slovenia; Spain (Baleares, Spain (mainland), Spanish North African Territories); Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe)
|FAO Marine Fishing Areas:|
Mediterranean and Black Sea
The size of the Mediterranean Sea subpopulation is unknown. Incomplete and somewhat anecdotal records from longstanding Bluefin Tuna (Thunnus thynnus) trap fisheries (“tonnara”) in Sicily, southern Sardinia, Tunisia, and the Balearic Islands (“almadraba”) suggest that incidental captures of adult Great White Sharks were not uncommon during the first six decades of the 20th century, with a general theme of declining records post-1970, often in line with the cessation of these fisheries themselves (Fergusson 2002, Morey et al. 2003).
In Italian waters at the Favignana tonnara, a number of adult specimens were landed between 1950 and 1982 and others observed but not caught. The last specimen encountered inside the trap nets was in May 1987 (Fergusson 2002). Similarly in traps off the Balearic Islands, 27 sharks were recorded between the 1920s and 1970s (Morey et al. 2003). A similar picture of increasingly sporadic records is repeated in the tonnara at Sidi Daoud, Tunisia, where a number of captures were made from the 1950s up to 1979, followed by lengthy periods with no specimens caught or observed. A total of 59 reliable captures of the species were reported along the Tunisian coasts from 1953–2012; 57% of them were registered after 2000 (Bradaï and Saïdi 2013). More recently, based on the capture of a pregnant female in the Gulf of Gabès (Saïdi et al. 2005) and other subsequent records, Bradaï and Saïdi (2013) suggested that Tunisian waters are a nursery area for this species.
In the Croatian Adriatic Sea, reports average at 0.0–0.4 sharks per year from the 1960s–1990s (De Maddalena 2000). Soldo and Jardas (2002a,b) reported a significant decline in Great White Shark records during the last decades of the 20th century compared to its occurrence since the mid-19th century. Hence, a disappearance of the species from Croatian Adriatic coastal waters was related to the disappearance of tuna due to new offshore tuna fishing practices that were introduced in the 1970s (Soldo and Jardas 2002a,b).
In the Sicilian Channel between 1950 and 2000, landing rates averaged around two specimens per year, but there have been no records since the mid 1990s from this area. In the eastern Mediterranean Sea (Aegean Sea and Levant) only one specimen was reported since 1993 from waters eastwards of the Ionian Sea, until 2008 when two new-borns were captured off the coast of Altınoluk (Edremit Bay, north Aegean Sea), by a commercial gillnet and a bottom longline (Kabasakal and Gedikoglu 2008). Two juvenile females were also captured in coastal waters of the northeast Aegean Sea in 2009 (Kabasakal et al. 2009). These records support the presumption of a breeding ground for the Great White Shark in the northeast Aegean Sea, extending from Edremit Bay to the north of Gokceada (Kabasakal et al. 2009). Small numbers of juvenile and neonatal specimens have been reported since the mid 1970s by demersal trawlers operating through the Sicilian Channel (Vacchi and Serena 1997) and small individuals have often been landed in parts of Tunisia by surface and demersal longliners (Fergusson 2002). However, confusion of young Great White Sharks with other mackerel sharks (family Lamnidae) is common in Mediterranean fisheries (Fergusson 1996).
More recent records include a newborn female that was caught by trawl net in waters surrounding the island of Lampedusa during 2009. Maliet et al. (2013) also reported the capture of a juvenile male off the Corsican coast in 2012, along with previous records from 1976 and 2011.
Records of the Great White Shark in the Mediterranean Sea are declining despite an increase in monitoring effort (Soldo et al. 2014). Based on genetic evidence, the Mediterranean Sea subpopulation should be considered a consequence of historical accident and female philopatry, rather than contemporary immigration from the Atlantic subpopulation. This reveals it to be at greater risk of local extinction than previously thought (Gubili et al. 2011), due to a lack of recruitment from any neighbouring water body. Based on the above information the species is suspected to have undergone a subpopulation decline of at least 80% over the past three-generation period (69 years).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
The Great White Shark is principally known as a pelagic dweller of temperate continental shelf waters, but also ranges into the open ocean far from land and near oceanic islands, and the coastal tropics. It is found from the surf-line and the intertidal zone to far offshore, and from the surface down to >250 m depth. It does not occur in fresh water, but penetrates saline bays and estuaries and during high tide it may swim into bays that have no water at low tide.
Maximum size is undetermined, but estimated at 600–640 cm total length (TL). Males mature between 360 and 400 cm TL with a maximum length of ~550 cm. Female size at maturity is uncertain, but thought to be between 450 and 500 cm TL, with a maximum length of 600 cm or more. Size at birth is ~120–150 cm TL (Ebert and Stehmann 2013). One specimen caught in the north Aegean Sea in 2008 is the smallest neonate from Mediterranean waters to date at 125.5 cm TL (Kabasakal and Gedikoglu 2008).
Age at maturity is estimated at 10–12 years based on counts of annually deposited vertebral growth rings (Cailliet et al. 1985). A mature female of 500 cm TL is estimated to have reached ~14–16 years. The average reproductive age is estimated at 17 years. Longevity was suspected as ~30 years (Cailliet et al. 1985) until a recent study showed the species may reach >70 years of age, based on testing the cartilage for radiocarbon residue from nuclear tests carried out by nations including the United States and Soviet Union during the 1950s and 1960s (Hamady et al. 2014). The species is known to have a relatively low intrinsic rebound potential (Smith et al. 1998) and the generation length has been calculated as 23 years (Mollet and Cailliet 2002).
Litter size ranges from three to 14 embryos, and reproduction is viviparous with oophagy. The gestation period is as yet unknown, but suspected to be about two years based on females returning to specific areas every other year (Ebert and Stehmann 2013). Parturition apparently occurs during the spring to late summer in warm-temperate neritic waters. To date, mating has not been reliably witnessed.
|Generation Length (years):||23|
|Movement patterns:||Full Migrant|
|Use and Trade:||There is no information available on the use and trade of this species in the Mediterranean region.|
Offshore records of the Great White Shark in the Mediterranean Sea have included captures across all size-classes made by pelagic longlines, bottom trawls, driftnets, and purse seines (e.g., Fergusson 2002; Soldo and Jardas 2002 a,b; Soldo 2007). Although no directed Mediterranean fishery has ever existed, there are attempts to capture, harpoon, or otherwise kill this species following cases of shark attack and/or associated media attention.
The Great White Shark readily approaches boats, scavenges from fishing nets or longlines, and devours hooked fish taken by rod-and-line or swordfish harpoon. This tendency increases their sensitivity to, and often results in, their accidental entrapment or deliberate killing by commercial fishermen. Many such cases have been recorded throughout the Mediterranean Sea for centuries. In certain regions such as Sicily, the species has traditionally been viewed negatively as manifesting a costly interference to fisheries. Presumption is that interactions with the growing number of Bluefin Tuna farms installed in the Mediterranean Sea, such as off Malta and parts of Spain and Libya, are inevitable and may result in new pressures being placed on the Great White Shark; equally, this may be a stern test of any local enforcement of conservation laws favouring the species.
The effect of habitat degradation might be especially acute in the Mediterranean Sea, where traditional prey such as the Monk Seal (Monachus monachus) and Bluefin Tuna have been significantly reduced in abundance. Additional related pressures are growing areas of intensive human inhabitation, especially for tourism, which overlap with the Great White Shark's habitat.
The Great White Shark was listed in Appendix III of the Convention on the International Trade in Endangered Species (CITES) in 2000, to regulate or ban international trade of teeth, jaws, fins and other parts. It was then added to Appendix II in 2005, in an attempt to ensure that trade be controlled to the extent that it is compatible with the species’ survival. A CITES listing might help slow trade in Great White Shark products, but will not eliminate low volume criminal trade. The species was added to both Appendices of the Convention on the Conservation of Migratory Species (CMS) in 2002 with the objective of providing a framework for the coordination of measures adopted by range states to improve the conservation of the species (Environment Australia 2002).
European Commission Regulation No 43/2009 prohibits Community vessels to fish for, to retain on board, to transship and to land the Great White Shark in all Community and non-Community waters; and also prohibits third country fishing vessels to fish for, to retain on board, to transship and to land this species in all Community waters. In 2013, the European Union (EU) banned the removal of shark fins on board vessels through Regulation No. 605/2013, in line with advice from the International Union for Conservation of Nature Species Survival Commission’s Shark Specialist Group and other shark fishery experts, in order to enhance enforcement of the 2003 EU ban on shark finning (Regulation No. 1185/2003) and facilitate improved shark fishery data collection.
The Great White Shark is listed as an endangered species under Appendix II of the Convention for the Protection of the Marine and Coastal Environment of the Mediterranean Sea (the Barcelona Convention: originally enacted in 1978 and amended in 1995). This convention has been signed and ratified by all coastal nations in the region. An implicit requirement of signatory nations is to preserve and manage sensitive fauna, including this species, as detailed under one of the Convention's protocols, the Protocol for Special Protected Areas and Biological Diversity of the Mediterranean Sea (known as the 'SPA Protocol'). In May 1999, Italy ratified the 'SPA Protocol' which having entered into force in 2000, meant that the Great White Shark now had protected status in Italian seas, including those around Sicily. Additionally, since October 1999 the species has been unilaterally protected in Maltese waters by specific legislation enacted under its Environment Protection Act No. 5 (1991) Flora and Fauna Protection (Amendment) Regulations 1999. All directed fisheries for elasmobranchs are prohibited in the coastal waters of Israel, though the Great White Shark is an exceedingly rare species in those waters. Within waters under Croatian jurisdiction it is proclaimed as a strictly protected species, but enforcement of said protection is as yet unclear.
The Great White Shark should be removed from international game fish record lists, and needs consistently rational and realistic treatment by entertainment and news media to counter its notoriety and inflated market value. Further research should also be conducted on the population size and trend of the species in the Mediterranean Sea, as well as catches monitored.
|Citation:||Soldo, A., Bradai, M.N. & Walls, R.H.L. 2016. Carcharodon carcharias. The IUCN Red List of Threatened Species 2016: e.T3855A16527829.Downloaded on 18 August 2018.|
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