Porbeagle shark (Lamna nasus)

Did You Know?

· The proposal to list the porbeagle shark in Appendix II of CITES will be considered for adoption at the next CITES meeting in March 2013.

Status
ESA Species of Concern - Atlantic: Newfoundland to New Jersey
CITES Appendix II - Proposed, throughout its range
CITES Appendix III - included by the European Union

Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Lamniformes
Family: Lamnidae
Genus: Lamna
Species: nasus

Species Description

Weight:	about 300 pounds (135 kg)
Length:	up to 11.5 feet (3.5 m)
Appearance:	dark bluish-grey backs with a white belly, they have a cylindrical body, conical head, and crescent-shaped tail
Lifespan:	around 65 years
Diet:	small fishes, sharks, squid
Behavior:	females give birth to live young that are nourished in utero with egg yolk for about 8-9 months

Porbeagle sharks are moderately large, spindle-shaped sharks. They are characterized by a cylindrical body, conical head and crescent-shaped tail. A distinctive white patch on the lower trailing edge of the first dorsal fin is used to identify fins in trade. They are warm-blooded, relatively slow growing and late maturing, long-lived, and bear only small numbers of young.

In the northwest Atlantic, males mature at approximately 8 years and 5.5 feet (1.5 m) length while females mature at 13 years and 6.4 feet (2 m) length. Life history characteristics vary between stocks. Northeast Atlantic porbeagle sharks are slightly slower growing than the northwestern stock. Both northern stocks are much larger, faster growing, and have a shorter life span than the smaller, longer-lived (~65 years old) southern porbeagles. They are ovoviviparous (that is, they give birth to live young that are nourished in utero with egg yolk), and females produce an average of four young per year. Gestation is thought to last 8 to 9 months.

Habitat
The porbeagle shark is a coastal species found in the upper pelagic zone from the surface to 200 m deep (occasionally to 350 m-700 m). They are most commonly reported on continental shelves and slopes from close inshore (especially in summer), to far offshore (where often associated with submerged banks and reefs). They are apparently less abundant in the high seas. Stocks segregate (at least in some regions) by age, reproductive stage, and sex. They undertake seasonal migrations within their stock area.

Mature females tagged off the Canadian coast appear to migrate 1,240 miles (2,000 km) south to give birth in deep water in the Sargasso Sea in the Central North Atlantic. Pups seem to follow the Gulf Stream to return north.

Distribution
Porbeagle sharks are found worldwide in a band between ~30° and 60°S in the Southern Hemisphere and mostly between 30° and 70°N in the North Atlantic Ocean and Mediterranean. Genetic studies identified two isolated populations, in the North Atlantic and the Southern oceans.

Population Trends
In 2005, the Northwest Atlantic population size was estimated to be about 190,000.

North and Southwest Atlantic stocks have identified marked declines to significantly less than 30% of historic baseline, according to the joint assessments by the Standing Committee on Research and Statistics of the International Commission for the Conservation of Atlantic Tunas and the International Council for the Exploration of the Seas.

Mediterranean catch per unit effort has declined to less than 5% of baseline.

More limited data from other Southern Hemisphere stocks--also a high value target and secondary catch of longline fisheries, but biologically less resilient to fisheries than North Atlantic stocks--also suggest declining trends.

Threats

targeted fisheries
shark fin trade
bycatch

This species is highly desired for the shark meat trade in Europe and some other areas. Fins are also moderately desirable in trade. They are caught in a variety of fisheries, including artisanal and small-scale commercial fisheries and commercial longline, gill net, drift net, and trawl fisheries. Sports fisheries exist in the U.S., New Zealand, and in some EU Member States.

Conservation Efforts
In October 2012, a number of countries agreed to sponsor a proposal to add porbeagle shark to Appendix II of CITES to provide further protections from the high demand for meat in international trade. The proposal will be considered for adoption at the next CITES meeting in March 2013.

The U.S. offered a similar proposal (co-sponsored by Palau) at the last CITES meeting in March 2010. The proposal garnered a simple majority but failed to acquire the two-thirds majority needed for adoption.

This species has also been a Species of Concern in the U.S. since 2006. The IUCN Red List status assessment is Vulnerable globally, but also varies by population: Critically Endangered in the Northeast Atlantic and the Mediterranean, Endangered in the Northwest Atlantic, and Near Threatened in the Southern Ocean.

Regulatory Overview
On January 22, 2010, we received a petition from WildEarth Guardians to list the porbeagle shark as threatened or endangered under the ESA throughout its entire range, or, as an alternative, to delineate the species into DPSs. On July 12, 2010, we published a notice that listing porbeagle sharks under the ESA is not warranted.

Key Documents
(All documents are in PDF format.)

Title	Federal Register	Date
CITES Appendix II Proposal		10/04/2012
New import and export requirements under CITES Appendix III inclusion		09/25/2012
90-Day Finding on Petitions to List the Porbeagle Shark; ESA-Listing Not Warranted	75 FR 39656	07/12/2010
Species of Concern Fact Sheet: Detailed	n/a	1/24/2010
Fact Sheet Highlights	n/a	12/28/2010

More Information

Updated: February 1, 2013