Swordfish
Xiphias gladius
Also
known as: broadbill
swordfish
Avg. Size: 40-100 Lbs (1)
Where: blue water
Fishing Methods: drift, troll
Rods: ocean
Food Quality 
(1) Can reach over 1000 Lbs,
but over fishing has
diminished the large ones to scarcity.
Habitat
Generally an oceanic species, the swordfish is primarily a midwater fish
at depths of 650-1970 feet (200-600 m) and water temperatures of 64 to
71°F (18-22°C). Although mainly a warm-water species, the swordfish
has the widest temperature tolerance of any billfish, and can be found
in waters from 41-80°F (5-27°C). The swordfish is commonly observed
in surface waters, although it is believed to swim to depths of 2,100
feet (650 m) or greater, where the water temperature may be just above
freezing. One adaptation which allows for swimming in such cold water
is the presence of a "brain heater," a large bundle of tissue
associated with one of the eye muscles, which insulates and warms the
brain. Blood is supplied to the tissue through a specialized vascular
heat exchanger, similar to the counter current exchange found in some
tunas. This helps prevent rapid cooling and damage to the brain as a result
of extreme vertical movements.
Food Habits
As opportunistic predators, swordfish feed at the surface as well as the
bottom of their depth range (>2,100 ft (650 m)) as evidenced by stomach
contents. They feed mostly upon pelagic fishes, and occasionally squids
and other cephalopods. At lower depths they feed upon demersal fishes.
The sword is apparently used in obtaining prey, as squid and cuttlefishes
commonly exhibit slashes to the body when taken from swordfish stomachs.
A recent study found the majority of large fish prey had been slashed,
while small prey items had been consumed whole. Larval swordfish feed
on zooplankton including other fish larvae. Juveniles eat squid, fishes,
and pelagic crustaceans.
Catch techniques: