Shortfin Mako Shark Essay, Research Paper

The shortfin mako shark is the fastest fish in the world. It is

capable of attaining speeds of up to 60 mph. It s dark red iron-rich

muscles on the side of the shark s body and especially on the tail

enable the shark to swim at these speeds. The speed of the mako

affects its physical characteristics, its eating habits, and its predators.

The average size of the shortfin mako shark is from 10 to 12 feet

and the largest size ever recorded was 18 feet. This fish weighs about

1,000 pounds. Its large heavy conico-cylindrical shaped body is

colored in such a way that it blends into the openwater environment

making them invisible to prey. Its back is a deep blue gray and its

underparts are snow white. The snout of this shark is bluntly pointed;

this helps the shark to speed through the water. Its first dorsal fin,

which is short starts behind the pectoral fins. This is unusual

compared to other sharks in the mako shark s family. The anal fin is

tiny compared to the dorsal fin. The mako has long gill slits and

strong caudal keels. The upper and lower lobes of the caudal fin are

of almost equal length. The mako has large eyes and is considered

one of the most beautiful common sharks.

The mako shark is found worldwide in temperate and tropical

seas. It is found from the Gulf of Maine to the equator and is most

densely populated in the Gulf of Mexico. These sharks are pelagic,

yet they are occasionally found inshore. They migrate seasonally

about 1,550 miles. In the summertime, mako sharks stay relatively

close to the shore, about 20 miles out. In the winter they migrate into

substantially deeper waters. They do this so that they can be in water

warmed by the gulf stream.

The Isurus oxyrinchus has a two year reproduction cycle.

Though few have been seen mating, scientists believe that the male

makos attack the females and force them to mate. They believe this

because often times females are found with horrible injuries to the

dorsal and pectoral fins following mating. Gestation takes about 12

months and reproduction is ovoviviparous. This means that the

mother carries the eggs internally until they are ready to hatch. While

in the womb the embryos are oviphagous (they feed on unfertilized

eggs). An average litter consists of 10 to 12 pups, each being about

two feet long.

The shortfin mako shark is a carnivorous animal that feeds on

swordfish, tuna, mackerel, tunny, herring, tarpon, and other large fish.

Once a 120 pound swordfish was found whole, sword and all, in the

stomach of a 730 pound mako. Often times these sharks swallow

their prey whole. The long, thin, sharp teeth of the mako enable it to

catch its agile prey. They are smooth edged and grow in rows. The

first two rows are used for obtaining prey, and the other multiple rows

are used to replace damaged of lost teeth. The amazing speed of this

fish also helps it to catch its food.

The mako shark s only enemy is man. This fish is hunted for

sport and used in products such as the oriental delicacy, shark fin

soup, and cartilage pills. The mako shark is a big game fish because

of its speed, size and the great fight it puts up when hooked. It can

leap 15 feet out of the water to free itself from the fisherman. Mako

sharks are dangerous and have attacked many humans and small

water crafts. Fisherman must be careful. Because the shark is

hunted so much and so often, some people worry about it becoming

endangered. There have been no collective studies on the mortality

or population dynamics of the mako shark, and no one knows how

many sharks there are in the world. Though the mako shark has no

conservation status at this time, the National Marine Fisheries Service

(NMFS) currently manages this shark. The NMFS has reduced

catches of the shark by commercial fishermen.

It seems all animals have there place in the ecosystem,

including the much feared mako shark. If sport fishing continues and

the shark s population dwindles, the disastrous effects would be felt

for all; even man, which at times believes he is above nature and not a

part of nature.