Sea Monster Monday: Swordfish
by brian lam
The Swordfish is part of the bill family of fish, the middle sized, as compared to the sailfish and marlin. If left to grown on its own, each can reach roughly 1500 pounds. From Caitlyn’s LetsBeSeaMonsters and Wiki:
The swordfish is named after its sharp beak resembling a sword (Latin gladius), which together with its streamlined physique allows it to cut through the water with great ease and agility. Contrary to belief, the “sword” is not used to spear, but instead may be used to slash at its prey in order to injure the prey animal, to make for an easier catch. Mainly the swordfish relies on its great speed, capable of reaching speeds up to 50 mph (80 km/h), and agility in the water to catch its prey. One possible defensive use for the sword-like bill is for protection from its few natural predators. The shortfin mako shark is one of the rare sea creatures big enough and fast enough to chase down and kill an adult swordfish, but they don’t always win. Sometimes in the struggle with a shark a swordfish can kill it by ramming it in the gills or belly.
While swordfish are cold-blooded animals, they have special organs next to their eyes to heat their eyes and also their brain. Temperatures of 10 to 15 °C above the surrounding water temperature have been measured. The heating of the eyes greatly improves the vision, and consequently improves their ability to catch prey.
They have been observed moving through schools of fish, thrashing their swords to kill or stun their prey and then quickly turning to consume their catch. In the western North Atlantic, squid is the most popular food item consumed. But fish, such as menhaden, mackerel, bluefish, silver hake, butterfish, and herring also contribute to the swordfish diet.Swordfish are vigorous, powerful fighters. When hooked or harpooned, they have been known to dive so quickly that they have impaled their swords into the ocean bottom up to their eyes. Although there are no reports of unprovoked attacks on humans, swordfish can be very dangerous when harpooned. They have run their swords through the planking of small boats when hurt.
The adults have few natural enemies, with the exception of large sharks, sperm whales, and orcas. They are easily frightened by small boats, yet paradoxically, large craft are often able to draw very near without scaring them. This makes swordfish easy to harpoon.
There are very few cases of swordfishes attacking people, but there is one case documented by a medical journal of a head injury by swordfish that caused death.
The famous research sub Alvin had to, after being attacked by a swordfish, be brought to the surface to have the fish removed from the vehicle’s skin, which was severely punctured. It was eaten for that night’s dinner.