Kingdom: Animalia

Phylum: Chordata

Class: Chondrichthyes

Order: Lamniformes

Family: Lamnidae

Genus: Lamna

Species: L. nasus

Physical Description

The porbeagle is a stout, heavy shark with a pointed, conical snout and a crescent-shaped caudal, or tail, fin. Its name is thought to arise from a combination of ‘porpoise’ referring to its shape, and ‘beagle’ referring to its hunting ability. It is dark bluish-grey to bluish-black on top, and white underneath. The first dorsal fin is large and triangular and has a white patch on the back of it, whilst the second dorsal fin is very small. The large pectoral fins, used for balancing and breaking, are situated behind long gill slits. The porbeagle, which has moderately large blade-like teeth. Females grow larger than males.

Biology and Behavior

The Porbeagle is a Highly migratory shark and also one of the most cold-tolerant sharks, in the northwest Atlantic mostly found from 5-10°C, known to temporarily tolerate salinities as low as 10 to follow its prey. Found singly and in schools and feeding aggregations. Feeds on small and medium-sized pelagic schooling species, other sharks, squid and demersal fishes (cod, white hake, red hake, haddock and cusk. These are When porbeagles mate, the male bites the female to hold her in place while they copulate. They are ovoviviparous sharks, and thus embryos develop within the female’s uterus without forming a placental connection. Instead, the foetuses obtain nutrition by feeding on fertilised eggs within the uterus. They possess fang-like teeth to tear open the egg capsules.

Habitat and Distribution

Most abundant on continental offshore fishing banks but also found far from land in ocean basins and occasionally close inshore. These are pelagic, epipelagic or littoral shark, moves generally along the continental shelves. The porbeagle occurs in the Atlantic Ocean in the northern hemisphere, and has a circumglobal distribution in the southern hemisphere; through the southern Atlantic, southern Indian Ocean, southern Pacific and Antarctic Ocean

Reference:

http://www.arkive.org/porbeagle/lamna-nasus/

http://www.fishbase.org/summary/88