Porbeagle Shark - Lamna nasus
Status: Vulnerable … The Porbeagle Shark is an endothermic shark, maintaining its body temperature above that of the surrounding seawater
Location: In the northern hemisphere, porbeagle sharks are found in the North Atlantic and Mediterranean only, whilst in the southern hemisphere they are found in a band around the globe through southern South America, southern Africa and southern Australasia.
Size: Usually approx. 200-300 cm long but with a maximum reported size of 365cm.
Habitat: Coastal and oceanic, temperate and cold-temperate waters worldwide (2 to 18°C, and up to 370 m depth).
The low reproductive capacity and high commercial value of porbeagle sharks makes this species highly vulnerable to over-exploitation and population depletion. The main threat to the porbeagle shark is overfishing, with both targeted long-line fisheries and trawl/gill net bycatch fisheries capturing the sharks for their highly valued meat, liver and fins. The meat of the porbeagle shark is among the most prized of all shark meat, particularly in Europe. In addition, the large fins of porbeagles are used in traditional Asian shark fin soup, and the liver oil is used for vitamin supplements. Extensive fishing in the 1960s and 1990s led to dramatic declines in this species, particularly in the North East Atlantic where the sub-population of this species is considered ‘critically endangered’. Since 2010 the EU has imposed a ban on EU and third party vessels targeting and landing porbeagle sharks in EU waters, and has banned EU vessels targeting porbeagles in international waters. EU vessels accidentally catching porbeagles must return them to sea and record the capture.
Porbeagle sharks are a valued game fish species for recreational fishing in Ireland and the UK, and most sea anglers release the sharks they catch.
Porbeagles are often solitary, but when schooling tend to aggregate in groups of single sex and similar size. They give birth to live young, which exhibit oophagy during gestation, that is, the developing young feed on unfertilised eggs, and female porbeagles can produce as many as 200,000 unfertilised eggs to serve this purpose. They feed almost entirely on fish, and despite their ‘fearsome’ appearance, porbeagles are not considered harmful to man, although they can be curious, and have often been recorded approaching divers carrying out maintenance on oil rigs.
Did you know?
- Porbeagle sharks are a member of the Lamnidae shark family, the same family as the Great White Shark.
- Porbeagles are endothermic, which means they generate internal body heat and can maintain their temperature above ambient temperature. This adaptation means they prefer waters lower than 18°C and have been recorded in seas as cold as 2 degrees C.
- A US study recorded distances of over 1,000 nautical miles (nm) travelled by tagged porbeagle sharks, though over 90% of the 143 sharks tagged moved less than 500 nm from their original tagging location. One porbeagle has been recorded crossing the Atlantic.
What MCS is doing:
- Lobbying for more and better management of offshore marine protected areas that should protect porbeagle shark habitats;
- Recommending seafood caught with minimal bycatch to chefs and restaurants, consumers and retailers;
- Successfully campaigning for reform of the Common Fisheries Policy, which regulates European commercial fishing, and now working to make sure it is properly implemented.