Porbeagle shark (Lamna 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.
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.
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.
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.
- targeted fisheries
- shark fin trade
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.
In October 2012, a number of countries agreed to sponsor a proposal to add all manta rays to Appendix II of CITES to provide further protections from the high demand in international trade. The proposal was passed at the CITES meeting in March 2013 and will become effective on September 14, 2014.
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.
|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||10/30/2013|
- IUCN Red List
- Report of the Fourth FAO panel for the assessment of CITES proposals
- IUCN/TRAFFIC Analysis of CITES proposals
- Essential Fish Habitat for Porbeagle Shark [pdf]
- NMFS Measures to Prevent Overfishing of Sharks
Updated: November 6, 2013