Porbeagle

Lamna nasus noaa

Rostre de maraiche-shark nose

Lamna nasus csiro-nfc

Porbeagle head

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Maraiche (dents)

Porbeagle two sizes

Porbeagle (Lamna nasus) is a species of mackerel shark found widely in the cold and temperate marine waters of the North Atlantic and Southern Hemisphere. It is notable for its distinctive girth, pointed snout, and the white patch on the trailing edge of its first dorsal fin. The porbeagle is a powerful swimmer and is known for its ability to maintain a higher body temperature than the surrounding water, an adaptation known as regional endothermy.

Description

The porbeagle can reach a length of up to 3.5 meters (11.5 feet) and weigh over 230 kilograms (500 pounds). It has a robust, spindle-shaped body with a pointed snout and large eyes. Its coloration is dark blue-gray to black on the back and white on the underside, with a unique white patch on the first dorsal fin.

Habitat and Distribution

Porbeagles are found in the cold and temperate waters of the North Atlantic and Southern Hemisphere. They prefer water temperatures between 5 and 10 degrees Celsius (41 to 50 degrees Fahrenheit) but can be found from the surface to depths of 1,370 meters (4,490 feet). Their range includes the North Atlantic from Newfoundland and Labrador to New Jersey in the west, and from Norway to the North Sea in the east, as well as parts of the Southern Hemisphere.

Behavior

Porbeagles are solitary or form small schools. They are highly migratory, moving towards the equator in winter and towards the poles in summer. Their diet primarily consists of bony fish and cephalopods. Porbeagles are known for their playful behavior, including leaping out of the water and interacting with objects floating in the sea.

Reproduction

The porbeagle is ovoviviparous, with embryos developing inside eggs that remain within the mother's body until they hatch. Females give birth to 1-5 pups every year or two, after a gestation period of about 8 to 9 months. Newborns are about 60-70 centimeters (24-28 inches) long.

Conservation Status

The porbeagle is listed as Vulnerable by the International Union for Conservation of Nature (IUCN) due to overfishing for its meat, fins, and liver oil. It is caught in targeted fisheries as well as bycatch in gear set for other species. Conservation efforts include management measures such as catch limits and closed fishing areas to protect their populations.

Cultural Significance

The porbeagle has been a subject of interest in sport fishing due to its size and strength. It is also featured in some cultural narratives and marine folklore, often admired for its power and beauty.

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