Alopias superciliosus

A record number of migratory sharks and rays were listed for global protection at the CMS COP11, held in Quito, Ecuador in 2014.  But, what comes next? 

10 Aug 2015


The bigeye thresher(Alopias superciliosus)  is listed by the IUCN on its Red List of Threatened Species as Vulnerable to extinction globally, due to severe, continued declines in their populations around the world.

A. superciliosus is circumglobal in distribution. Ongoing analysis has indicated no structuring of populations of A. superciliosus within the Pacific Ocean, but significant genetic divergence between Atlantic and Indo-Pacific populations (Trejo 2005). The existence of separate Indian Ocean and Pacific Ocean stocks is as yet unconfirmed. 

Alopias sppall exhibit particularly low productivity and growth rates meaning they have a high susceptibility to anthropogenic pressure and show slow recovery from overexploitation. A. superciliosus has the lowest fecundity and thus, exceptionally low potential annual rate of population increase (0.002-0.009 or 1.6%) under sustainable exploitation (Smith et al. 2008; Cortés 2008; Dulvy et al. 2008). This makes them particularly vulnerable to any level of fisheries exploitation, whether targeted or caught as bycatch in fisheries for other species. Alopias spp. have been identified as among the shark species most at risk from anthropogenic pressure worldwide (Oldfield et al 2012). They are caught and killed in both target and bycatch fisheries in domestic waters and the high seas globally. Catch is often unmanaged or only managed over part of their range.The fins are an important component of the global shark fin trade, with the last comprehensive study of the trade identifying them as accounting for approximately 2.3 % of sharks in the Hong Kong market. This is equivalent to up to four million thresher sharks per year (Clarke et al. 2006 A and B).




Assessment information
CMS InstrumentsCMS, Sharks (2016)
IUCN StatusVulnerable
Date of entry in Appendix II2014
Geographic range
Countries Angola, Argentina, Australia, Bahamas, Brazil, China, Costa Rica, Cuba, Ecuador, El Salvador, French Polynesia, Greece, Guatemala, Guinea, Israel, Italy, Japan, Madagascar, Maldives, Mexico, Morocco, New Caledonia (France), New Zealand, Nicaragua, Panama, Portugal, Senegal, Sierra Leone, Somalia, South Africa, Spain, Sri Lanka, Türkiye, United States Minor Outlying Islands, United States of America, Uruguay, Venezuela, Viet Nam
Common names
EnglishBigeye Thresher Shark
FrenchRenard à Gros Yeux
SpanishZorro Ojón
Scientific name Alopias superciliosus
AuthorLowe 1841
Standard referenceEschmeyer, W.N. (1990). Catalogue of the Genera of Recent Fishes. California Academy of Sciences, San Francisco, California.

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