Sphyrna lewini


The scalloped hammerhead shark (Sphyrna lewini) is listed as globally endangered on the IUCN’s Red List. The principal conservation problem facing this species is its population decline. This problem, driven by the high economic value of its fins and the consumption of its meat, has led to the species being overfished during all stages of its lifecycle.

Sphyrna lewini is a circumglobal shark species native to coastal warm temperate and tropical seas. Its highly migratory nature, slow growth, and lengthy gestation period place this common bycatch species at risk to fishing practices on the high seas, at oceanic congregation sites, and throughout coastal birth zones.

Given these current fishing pressures, in addition to a lack of management strategies by RFMOs, high rates of Sphyrna lewini captures pose a serious threat to the specie’s survival. Because of difficulties in differentiating between the genus’ species, estimates of trends in abundance are often grouped together as a complex. Abundance trend analyses of catch-rate data for the hammerhead complex of Sphyrna lewini, including Sphyrna mokarran and Sphyrna zygaena, have reported large declines, ranging from 60-99% over recent years.

Given S. lewini’s present situation, one that includes its overutilization, inadequacy of existing regulatory mechanisms, and other natural or manmade threats, inclusion of the species in CMS Appendix II is necessary in order to begin to restore its populations.

Assessment information
CMS InstrumentsCMS, Sharks (2016)
IUCN StatusVulnerable
Date of entry in Appendix II2014
Geographic range
Countries Angola, Anguilla (UK), Antigua and Barbuda, Aruba (Netherlands), Australia, Bahamas, Bahrain, Barbados, Belize, Benin, Brazil, Cabo Verde, Cameroon, Cayman Islands (UK), China, Colombia, Congo (Brazzaville), Costa Rica, Cuba, Côte d'Ivoire, Djibouti, Dominica, Dominican Republic, Ecuador, Egypt, El Salvador, Equatorial Guinea, Eritrea, French Guiana (France), Gabon, Gambia, Ghana, Grenada, Guadeloupe (France), Guinea, Guinea-Bissau, Guyana, Haiti, Honduras, India, Indonesia, Iran, Iraq, Jamaica, Japan, Kuwait, Liberia, Maldives, Mauritania, Mexico, Myanmar, Namibia, New Caledonia (France), Nicaragua, Nigeria, Oman, Pakistan, Panama, Philippines, Puerto Rico (USA), Qatar, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Saudi Arabia, Senegal, Sierra Leone, South Africa, Suriname, São Tomé and Príncipe, Thailand, Togo, Trinidad and Tobago, United Arab Emirates, United States of America, Uruguay, Venezuela, Viet Nam, Yemen
Common names
EnglishScalloped hammerhead shark
FrenchRequin-marteau halicorne
SpanishTiburón martillo común
Scientific name Sphyrna lewini
AuthorGriffith and Smith 1834
Standard referenceEschmeyer, W.N. (1990). Catalogue of the Genera of Recent Fishes. California Academy of Sciences, San Francisco, California.

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