Porbeagle Shark

Porbeagle Shark
    • Scientific name: Lamna nasus
    • Also known as: Mackerel Shark, Porgie
    • Size: Up to 12ft and 600lbs. In UK waters typically 7-8ft and 300lbs.
    • UK minimum size: All UK shark species have a default minimum weight of 40lbs/18kg (shore) and 50lbs/23kg (boat).
    • UK shore caught record: N/a
    • Distribution: Found all around the UK in deep waters, usually several miles offshore. Range extends throughout the North Atlantic and Mediterranean and a separate population is found in the southern hemisphere. Absent from the warmer waters around the equator.
    • Feeds on: Pelagic fish such as mackerel and herring, although will also feed on bottom-dwelling fish.
    • ICUN Status: VU (Vulnerable)
    • Description: Stout, compact, powerfully built shark. Dorsal and pectoral fins are large and tail is narrow and crescent shaped. Body and fins are grey while flanks and underside are white. There are five gill slits on each side of the body. Skin is rough. Distinctive white mark on trailing edge of dorsal fin, tiny second dorsal and anal fin. Pointed snout and black eyes with no protective eyelids. Large mouth with powerful jaws is full of rows of large sharp teeth.
The porbeagle shark is a powerful, squat-bodied shark which can be found all around the British Isles in the warm summer months. It generally stays way out to sea, where it actively hunts in mid-water for mackerel, herring and squid but will also venture to the seabed to take demersal fish such as cod, whiting and flatfish. Its alternative name of mackerel shark is due to it feeding on this species, and not because it looks like, or is related to mackerel. Occasionally porbeagle shark may come close to shore if prey is abundant there.
Porbeagle Shark Distribution

Map showing where porbeagle shark can be found throughout the world.

Porbeagle sharks are found all around the world. It is found on both sides of the North Atlantic, around the coasts of North Africa, in the Mediterranean and around Australia and New Zealand. Populations in the northern and southern hemispheres are thought to be completely separate and do not intermix. Porbeagle sharks are found all around the UK and many people are surprised to hear that a shark of such size can be found in the tempeate waters around the UK with some regularity. The following list shows just some of the large porbeagle sharks which have been caught in British waters in recent years:

Porbeage sharks (like other sharks in the Lamnidae family) have an unusual system of regulating their body temperature. Heat generated by muscles is conserved within the body by specialised blood vessels. This gives the porbeagle shark the ability to elevate its body temperature and keep itself warmer than the water which surrounds it. This means the porbeagle shark can live happily in colder waters, hunt for long and and in deeper water, and have many of the advantages of warm-blooded creatures.

Porbeagle Sharks as a Commercial Fish

Porbeagle sharks are commercially valuable. Their flesh is highly prized in restaurants and fishmongers, and costs considerably more per kilo than other shark species. The fins are also exported to Asia where there is high demand for shark fin soup. Commercial vessels specifically targeting porbeagle shark tend to use long-lines, although they will also be caught in the nets of trawlers as bycatch who will retain the valuable porbeagle shark. This fishing pressure has led to porbeagle sharks becoming an at risk species. Overall, the IUCN (International Union for the Conservation of Nature) classes porbeagle shark as Vulnerable. However, this masks how badly the numbers of porbeagle have declined in certain areas – in the western North Atlantic they are classed as Endangered, and in the eastern North Atlantic and Mediterranean they are Critically Endangered.

Porbeagle Shark Longline

A porbeagle shark caught on a commercial long-line.

There have been efforts to reverse the decline of porbeagle sharks in European waters. This species now has a zero TAC (Total Allowable Catch) throughout all European waters, and it is illegal for European vessels fishing in international waters to target, retain, land or transfer porbeagle sharks.  On the North American side of the Atlantic similar efforts are being put into preserving porbeagle shark populations. US and Candaian quotas have been cut down and known porbeagle breeding grounds (such as the one off the coast of Newfoundland) are closed to commercial fishing. Recreational fishing for porbeagles is also restricted. However, porbeagle sharks grow slowly and mature late. They also have a long gestation period of nine months and a low number of pups are born (usually four but sometimes only one). All of this means that it will take a very long time to see porbeagle numbers recover, even if the conservation measures which are put in place are effective.

Sport Fishing for Porbeagle Shark

Captured Porbeagle

A captured porbeagle shark.

Porbeagle sharks are a very popular sport fish due to their size, power and the prestige of catching a large shark species. There are charter boats that will take anglers out fishing for porbeagle sharks in areas where they are found around the UK such as off the coast of Cornwall and parts of Ireland and Wales. Porbeagle are also found in the North Sea, but not with sufficient numbers to allow charter boats to target them. Rigs used from boats usually consist of a 10/0 – 12/0 sized hook in a very heavy pattern attached to wire line of several hundred pound breaking strain in order to withstand the teeth of the porbeagle. This then runs to a five or six metre trace of heavy monofilament line with a breaking strain around 200-300lb. This heavy monofilament is necessary as the rough skin of the porbeagle is so abrasive it can cut through weaker line. When porbeagles are targeted the full big game set up of heavy boat rods, large big-game multipliers, butt pads and harnesses are used, as a hooked shark will need to be played for some time before it can be reeled in. A full mackerel is the obvious bait and it is usually fished between ten and thirty metres below the surface, sometimes on a float set up. Rubby dubby is also used to attract sharks to the area. Usually any shark the size of a porbeagle is classed as caught as soon as it is pulled alongside the boat as it can be too dangerous to bring them on board smaller vessels, but on larger charter boats they may be brought on board to be photographed. Most charter skippers operate a strict catch and return policy as porbeagle stocks are under enough pressure without recreational anglers killing fish and numbers need to be protected.

Attacks on Humans

Although porbeagle sharks are physically capable of attacking humans they rarely do so. There have been only a handful of confirmed cases of porbeagle attacks on humans. Unsurprisingly, porbeagle sharks do not take kindly to being caught on rod and line, and most injuries sustained by people are when the shark is caught and brought on board a boat. One angler had his foot bitten by a porbeagle after hauling the shark on board, but little damage was done as he was wearing steel toe-capped boots. There has never been a confirmed case of a porbeagle shark killing a human being.

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