Hammerhead Sharks (Sphyrna spp.)

To conserve and protect hammerhead sharks, Brazil, Costa Rica, and Honduras submitted a proposal to include three species of hammerhead sharks--scalloped hammerhead (Sphyrna lewini), great hammerhead (Sphyrna mokarran), and smooth hammerhead (Sphyrna zygaena)-- in CITES Appendix II.

Scalloped hammerhead sharks were proposed for listing in Appendix II because they are highly valued in the fin trade and are also taken as bycatch in global fisheries. Great hammerheads and smooth hammerheads were proposed for listing in Appendix II due to their similarity of appearance to scalloped hammerhead sharks. CITES allows for the listing of species as "look-alikes" (i.e. species of which the specimens in trade look like those of species listed for conservation reasons).

Scalloped Hammerhead Shark (Sphyrna lewini)


CITES Status | Taxonomy | Description | Habitat | Distribution | Threats

 

CITES Status

great-hammerhead

Great Hammerhead Shark, Credit: Copyright © Brian Skerry

Currently a candidate for ESA listing throughout its range and included in Appendix III at the request of Costa Rica. Proposed for Appendix II listing by Brazil, Colombia, Costa Rica, Ecuador, Honduras, Mexico and the European Union.

Taxonomy

Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Carcharhiniformes
Family: Sphyrnidae
Genus: Sphyrna
Species: lewini

Description

Scalloped hammerhead sharks are moderately large sharks with a global distribution. The eight or so species of hammerhead sharks are characterized by the flat, extended head or "cephalofoil." The cephalofoil of a scalloped hammerhead shark is characterized by an indentation located centrally on the front margin of the broadly arched head. Two more indentations flank the main central indentation, giving this hammerhead a "scalloped" appearance.

They feed on crustaceans, teleosts, cephalopods and rays.

Habitat

The scalloped hammerhead shark is a coastal pelagic species that can also be found in ocean waters and occurs over continental and insular shelves and adjacent to deeper water. It has been observed close inshore and even entering estuarine habitats, as well as offshore to depths of 1000m. Adult aggregations are common at seamounts, especially near the Galapagos, Malpelo, Cocos and Revillagigedo Islands and within the Gulf of California, but otherwise adults can be solitary or occur in pairs.

Distribution

Scalloped hammerhead sharks are found worldwide residing in coastal warm temperate and tropical seas in the Atlantic, Pacific, and Indian Oceans between 46°N and 36°S to depths of 1000 meters.

Threats

  • targeted fisheries, shark fin trade
  • bycatch

This species is highly desired for the shark fin trade because of its fin size and high fin ray count. They are caught in a variety of fisheries including artisanal and small-scale commercial fisheries, bottom longlines as well as offshore pelagic longlines, gillnets, etc. They are valuable in the international fin and are often used to make shark fin soup. Compilation of market prices from auction records indicates an average, wholesale, unprocessed fin market value of US $50-100/lb.

In addition to falling victim to bycatch and the shark fin trade, different hammerhead species are often misidentified in the water, making them increasingly vulnerable to accidental harvest. The majority of the hammerhead fins that were misidentified were found to be of another species of hammerhead, demonstrating that fin traders are able to differentiate between hammerhead fins and other shark species, but not always to the species level.

Additional Information

The United States strongly supports shark and manta ray proposals and applauds the leadership of the proponent countries. What are the benefits of listing a marine species in CITES appendix II? Click here to learn more.

  • Read more about the Scalloped Hammerhead at the IUCN Red List website.