Lamnidae

Porbeagle

Lamna nasus

A white tipped elder in subzero seas

• Gray
• White
• Cross-climate
• Temperate
• Tropical
• Globally widespread
• Marine fish
• Fusiform
• Large

Dressed in an immaculate charcoal-blue mantle set off by an unmistakable white dorsal patch, the porbeagle is an imposing, cold-adapted pelagic mackerel shark inhabiting the boreal waters of the North Atlantic and Southern Oceans. Its heavy, stout fusiform body presents a sharply pointed conical snout and large, coal-black eyes without nictitating membranes. The definitive identification mark is a brilliant snow-white patch on the trailing rear margin of the first dorsal fin, accompanied by smooth-edged lanceolate teeth with distinct lateral basal cusplets. Possessing advanced countercurrent vascular heat exchangers (rete mirabile), it maintains muscle and visceral temperatures up to ten degrees Celsius above surrounding water, powering remarkable agility in cold subarctic seas. Found in boreal continental shelf and oceanic waters from the surface down to seven hundred meters depth, it thrives between two and eighteen degrees Celsius, hunting schooling herrings, mackerels, pilchards, cod, and squids. Aplacental viviparous with uterine oophagy, maximum recorded total length reaches three hundred and fifty-five centimetres.

Sources: NOAA Fisheries — Porbeagle Shark, Lamna nasus