The Porbeagle Shark is also known
as mackerel shark.
Scientific name........Lamna Nasus
Other Common name..........Mackerel shark
The Porbeagle and its North Pacific relative, the Salmon shark are
the smallest of the five mackerel sharks. These sharks have a stout
torpedo shaped body, pointed snout and two keels on the tail. The
Porbeagle and Salmon sharks are the only sharks with a secondary
keel at the base of their crescent-shaped tails. This efficiently
cuts the water in its side-to-side swimming movement. There is no
white patch above the pectoral fin, but a very distinctive white
free rear tip to the first dorsal fin.
These sharks can reach a maximum length of 12 feet and weight up to
They have very sharp, moderately large teeth, with blade
smooth-edged with basal cusplets.
They are a dark blue-gray to brown dorsally and white underneath. It
has a patch of white on the trailing edge of the first dorsal fin.
The Porbeagle sharks feed on squid, cod, hake, flounder, and other
bottom dwelling fish.
Porbeagles are migratory and moves inshore and to surface in
summer, winters offshore in deeper water to depths of 1,212 feet.
Populations are segregated by age (size) and sex. They are
inquisitive, may approach boats and divers.
They inhabit in cold waters of North Atlantic, South Atlantic, and
South Pacific. They are found inshore to continental offshore
fishing banks, occasionally open ocean.
The mackerel sharks are unique among sharks for their
heat-exchanging circulatory system, which makes them, functionally,
warm-blooded. They can capture the heat generated by their swimming
muscles and, through a complicated arrangement of microscopic
arteries and veins, use it to heat the blood. This blood is directed
throughout their body, to the muscles, internal organs, and brain.
As a result, their body temperature is higher than that of the
surrounding water. This gives them an increased muscle strength and
allows more rapid nervous-system activity. The Porbeagle has
achieved the greatest body temperature elevation. It's body can be
20 F (11C) warmer than the frigid North Atlantic Ocean that it
It reproduces viviparously, without a placental connection. As with
other mackerel sharks, the older embryos feed on some of the eggs
and smaller embryos in the uterus.
Porbeagles are strong, fast swimmers that are capable of rapid
Common, although some statistics have been reported that some
populations have been depleted due to commercial fisheries for high
value of meat, and also a game fish.