The scalloped hammerhead shark (Sphyrna lewini) known in spanish as “Cornuda”, belongs to the Family Sphyrnidae. Its most destinguished characteristic is its hammer shaped head. We include here some aditional information of this species.

 

IDENTIFICATION

  • It has two lateral slits on both sides of its head and a central one
  • Differentiated from S. mokarran because it has the posterior border of the pelvic fins clearly straight
  • Differentiated from S. zygaena because it has the  posterior extreme border of  the second dorsal fin free and  elongated , almost reaching the origin of the caudal fin
  • Irregular, diffused and decolored spots on both sides of the body
  • Black spots few defined on the tip of the pelvic fins
  • Teeth Irregular, triangular, narrow and thin apexed

HABITAT AND BIOLOGY

New born and juveniles spend the first stages of its life on coastal habitats like bays and estuaries. Adults grouped in schools around sea mounts and oceanic islands. Highly migartory in tropical and subtropical waters. Regular size 429 cm., Catched by the demersal longline fisheries, with individuals from 80 to 120 cm. Viviparous hosting 10 to 30 embryos.

FISHING

Frequently catched but in low quantities. Adults trapped by pelagic longliners, females catched by gill nets when they visit coastal waters to give birth to its breeding. Juveniles catched by trawl and gill nets.

USES

Meat of the juveniles marketed as “cornuda rozada” and “bolillo” for the national consumption. Adults meat usually used as bait. Fins, liver and skin are also used for the international market. Fins are national and internationally marketed as “grey shark” fins.

CONSERVATION STATUS (IUCN red list)

Endangered

INFORMATION SOURCES

Guía para la identificación de las especies de tiburones más comunes del Pacífico de Costa Rica

http://www.iucnredlist.org/details/39385/0

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Watch the tagging of a hammerhead during an expedition to Cocos Island