Scalloped Hammerhead Shark

Protected Status

ESA Endangered

Eastern Pacific DPS

ESA Endangered - Foreign

Eastern Atlantic DPS

ESA Threatened

Central & Southwest Atlantic DPS
Indo-West Pacific DPS

CITES Appendix II

Throughout Its Range

SPAW Annex III

Throughout the Wider Caribbean Region

Quick Facts

Weight

Up to 335 pounds

Length

Up to 11 feet

Lifespan

Up to 30 years

Threats

Bycatch, Overfishing

Region

Pacific Islands, Southeast, West Coast

Scalloped hammerhead shark. Credit: NOAA Fisheries

About the Species

Scalloped hammerhead shark. Credit: NOAA Fisheries

Scalloped hammerhead sharks are moderately large sharks with a global distribution. The most distinguishing characteristic of this shark is its "hammer-shaped" head. They are threatened by commercial fishing, mainly for the shark fin trade. Two distinct population segments of the scalloped hammerhead shark are listed as endangered and two are listed as threatened under the Endangered Species Act (ESA).

NOAA Fisheries is committed to conserving and protecting scalloped hammerhead sharks. Our scientists and partners use a variety of innovative techniques to study and protect this species.

Where They Live

The scalloped hammerhead shark can be found in coastal warm temperate and tropical seas worldwide. In the western Atlantic Ocean, the scalloped hammerhead range extends from the northeast coast of the United States (from New Jersey to Florida) to Brazil, including the Gulf of America (formerly Gulf of Mexico) and the Caribbean Sea. In the eastern Atlantic, it can be found from the Mediterranean to Namibia. Populations in the Indian Ocean are found in the following locations: South Africa and the Red Sea to Pakistan, India, and Myanmar, and in the western Pacific, the scalloped hammerhead can be found from Japan and China to New Caledonia, including throughout the Philippines, Indonesia, off Australia. Distribution in the eastern Pacific Ocean extends from the coast of southern California (U.S.), including the Gulf of California, to Ecuador and possibly Peru, and off waters of Hawaii (U.S.) and Tahiti.

World map providing approximate representation of the scalloped hammerhead shark's range

Scientific Classification

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

Last updated by NOAA Fisheries on 02/26/2025

Related Species

Bonnethead Shark

Management Overview

The scalloped hammerhead shark Eastern Pacific distinct population segment (DPS) and Eastern Atlantic DPS are listed as endangered and the Central & Southwest Atlantic DPS and Indo-West Pacific DPS are listed as threatened under the Endangered Species Act.

Additionally, the scalloped hammerhead shark is listed under:

Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)
Annex III of the Protocol for Specially Protected Areas and Wildlife (SPAW)

Regulatory History

On August 14, 2011, NOAA Fisheries received a petition from WildEarth Guardians and Friends of Animals to list the scalloped hammerhead shark as threatened or endangered under the ESA throughout its entire range, or as an alternative, to delineate the species into distinct population segments. On November 28, 2011, we published a notice that listing may be warranted. We published the proposed rule to list under the ESA and a status review of the species in April 2013. In July 2014, we listed four distinct population segments under the ESA.

Key Actions and Documents

Actions & Documents

Scalloped Hammerhead Shark 5-Year Review

In 2019, NOAA Fisheries announced its intent to conduct a 5-year review for the four distinct population segments (DPSs) of the scalloped hammerhead shark (Sphyrna lewini): Eastern Atlantic DPS Eastern Pacific DPS Central Southwest Atlantic…

Notice of Initiation of 5-year review; request for information (84 FR 46938, Se…

Scalloped Hammerhead Shark 5-Year Review (2020)

Notice,

Pacific Islands

Southeast

West Coast

Foreign

Published

May 14, 2020

Listing of the Scalloped Hammerhead Shark Under the ESA

In response to a petition submitted by WildEarth Guardians and Friends of Animals, we, NOAA Fisheries, are issuing a final determination to list the Central and Southwest (SW) Atlantic Distinct Population Segment (DPS) and the Indo-West Pacific DPS of…

Final Rule

Effective

September 2, 2014

Determination on the Designation of Critical Habitat for Scalloped Hammerhead Shark

We, NOAA Fisheries, find that there are no marine areas within the jurisdiction of the United States that meet the definition of critical habitat for the Central and Southwest (Central and SW) Atlantic Distinction Population Segment (DPS), Indo-West…

Notice (80 FR 71774, November 17, 2015)

Notice,

National

Published

November 17, 2015

Last updated by NOAA Fisheries on 02/26/2025

Documents

Document