Porbeagle - a top predator in Irish waters!

The porbeagle is a shark species, belonging to the Mackerel shark family; the same family as the great White shark, of which they are commonly mistaken by the media due to a very similar look; porbeagles however are in fact around half the size!

Harbour Porpoise are the most common cetacean species in Northern Irish Waters! Like the porbeagle, they have streamline bodies to aid movement through the waters!

*Credit: Niki Clear*

The name "porbeagle" derives from a few other animals! "Por" comes from their porpoise-shaped bodies, and "beagle" comes from their hunting like behaviours! They use their incredibly sensitive sense of smell to sniff blood or other smells from their prey!

Porbeagle Distribution Worldwide — *Credit: IUCN*

Porbeagles are found worldwide below latitudes of 30 degrees so they live comfortably in Northern Irish and Irish waters. The majority of sightings in the South are around Lough Swilly, Galway, Clare and Cork (between June and October); Malin Head is also a hot-spot! Porbeagles are easily identified by their dorsal fin, 5 gill slits along either side of its body, and large black eyes. Whilst there are different populations and sub-populations worldwide, sharks found in Irish waters grow to an average of 1.5-2 meters; weighing 135kg. Even with this size, no unprovoked attacks on humans have been recorded!

Porbeagles feed on pelagic fish, usually herring or mackerel; they can keep up with these speedy food-items due to their streamline bodies and endothermic (warm-blooded) properties. This means they can maintain a higher body temperature than the water around them by trapping heat, allowing the muscles they use for movement to generate a more considerable amount of power. Being able to maintain warm blood enables them to live in water temperatures as low as two degrees Celsius; another reason why they are found in the cold Irish waters! Their strong swimming ability aids in long migrations; it is thought the females leave Northern Irish waters in March - but we're not sure where they go!

Historically, porbeagles were an important commercial species, being hunted for their high price meat; similar to expensive swordfish meat when sold as steaks. The meat was eaten worldwide including European countries such as Italy (called smerigilo) and Germany. Porbeagle fisheries were common in the early and middle 20^th century in Ireland and populations saw a dramatic decline, causing them to now be critically endangered in Irish waters - that is one step away from extinct! The recovery of porbeagle populations is difficult due to them having a long gestation (developing of shark pups within mothers) as well as small litter sizes; usually between 1 and 5 pups. It is estimated that it takes 14 years for the population to double in size even without any external pressures such as fishing.

Conservation efforts have been made in the UK, Ireland and other countries. Retailers, restaurants and consumers are highly recommended to purchase seafood where bycatch has been minimal. The species is also subject to “zero-total allowable catch” in EU waters, basically meaning that it is illegal to target it intentionally! It is also unlawful to retain the shark on-board a fishing vessel – if accidentally caught, it must be returned immediately (if dead it must not be kept, and recorded). The species is also included on the Northern Ireland Priority Species list. Sea Deep trains anglers to tag porbeagles, so that abundance and distribution around Northern Ireland can be estimated. The tag data are used to work out where they are most densely populated, with the hope that these areas can be protected.