Scalloped Hammerhead Shark (Sphyrna lewini)
Scalloped Hammerhead Shark
Did You Know?
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.
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.
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. Distinct Population Segment (DPS) boundaries are shown in the map below:
- targeted fisheries, shark fin trade
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 about $50-100 per pound.
In March 2013, at the CITES Conference of the Parties meeting in Bangkok, member nations, referred to as "Parties," voted in support of listing three species of hammerhead sharks (scalloped, smooth, and great) in CITES Appendix II—an action that means increased protection, but still allows legal and sustainable trade. This CITES listing is effective as of September 14, 2014. Export of their fins requires permits that ensure the products were legally acquired and that the Scientific Authority of the State of export has advised that such export is not detrimental to the survival of the species.
On August 14, 2011, we received a petition from WildEarth Guardians and Friends of Animals to list the scalloped hammerhead shark (Sphyrna lewini) as threatened or endangered under the ESA throughout its entire range, or, as an alternative, to delineate the species into DPSs. On November 28, 2011, we published a notice that listing may be warranted, and we commenced a status review. We published the proposed rule to list and status review in April 2013.
Final Rule to List 4 DPSs under the ESA
|79 FR 38213||07/03/2014|
Proposed Endangered and Threatened Listing Determinations for 4 Distinct Population Segments (DPSs)
|78 FR 20717||04/05/2013|
||78 FR 20717||04/05/2013|
|CITES Appendix II Proposal||10/04/2012|
|90-Day Finding on a Petition To List the Scalloped Hammerhead Shark as Threatened or Endangered and Initiation of Status Review||76 FR 72891||11/28/2011|
|Petition to List Under the ESA||n/a||08/2011|
- CITES: Sharks and manta rays
- NOAA's role in CITES
- CITES conference takes decisive action to halt decline sharks, other species
- CITES Implementation: U.S. Fish and Wildlife
- IUCN Red List
Updated: October 9, 2014