The
shortfin mako shark,
Isurus oxyrinchus ("sharp nose"), is a large
mackerel shark. Along with the closely related
longfin mako (
Isurus paucus) it is commonly referred to as a "
mako shark".
Etymology
In 1809,
Constantine Rafinesque first described shortfin mako and coined the name Isurus oxyrinchus (
Isurus means "the same tail", oxyrinchus means "pointy snout"). "Mako" comes from the
Māori language, meaning either the shark or a shark tooth. It may have originated in a
dialectal variation as it is similar to the common words for shark in a number of
Polynesian languages—
makō in the
Kāi Tahu Māori dialect,
mangō in other Māori dialects,
Richard Taylor's A leaf from the natural history of New Zealand (1848) is more elaborate: "Mako, the shark which has the tooth so highly prized by the Maoris".
Anatomy and appearance
Although both sexes grow at about the same rate, females are thought to have a longer
life span, and generally grow larger and more robust. This species grows to an average length of and to a weight of approximately . The largest reported male specimen weighed and measured , although a near record-sized female shortfin mako measuring weighed .
The shortfin is sleek and spindle-shaped with a long conical snout. Mako sharks have a more
hydrodynamic shape than any shark other than the
salmon shark. Combined with the lamnidae's typical high
aerobic muscle mass, this enables its spectacular speed and movements with great agility.
It has a crescent shaped caudal (tail) fin. The caudal base has a distinct caudal keel. Its second dorsal fin is much smaller than the first. The apexes of pectoral fin and first dorsal fin are rounded in younger makos. Shortfin mako skin has very abrasive placoid scales to reduce friction during swimming, like the dimples of a golf ball.
Distinguishing characteristics
Teeth are visible even when the mouth is closed
Teeth are long and slender with smooth-edged cusps
Distinct countershading, dorsally blue and ventrally white
Moderately short
pectoral fins
In the western Atlantic it can be found from Argentina and the Gulf of Mexico to Browns Bank off of Nova Scotia. In Canadian waters these sharks are neither abundant nor rare. Swordfish are a good indication of shortfin makos as the former is a source of food and prefers similar environmental conditions.
Shortfin makos travel long distances to seek prey or mates. In December 1998, a female tagged off California was captured in the central Pacific by a Japanese research vessel, meaning this fish traveled over . Another swam in 37 days, averaging a day.
Shortfin consume 3% of its weight each day and takes about 1.5–2 days to digest an average-sized meal. By comparison, an inactive species such as the sandbar shark consumes 0.6% of its weight a day and takes 3 to 4 days to digest it. An analysis of the stomach contents of 399 male and female mako sharks ranging from suggest makos from Cape Hatteras to the Grand Banks prefer bluefish, constituting 77.5% of the diet by volume. The average capacity of the stomach was 10% of the total weight. Shortfin makos consumed 4.3% to 14.5% of the available bluefish between Cape Hatteras and Georges Bank.
Shortfin over have interior teeth considerably wider and flatter than smaller makos, which enables them to prey effectively upon dolphins, swordfish, and other sharks. An amateur videotape, taken in Pacific waters, shows a moribund spotted dolphin whose tail was almost completely severed, with a very large shortfin mako circling the dying dolphin. Makos also have the tendency to scavenge long-lined and netted fish.
Its endothermic constitution partly accounts for its relatively great speed.
Like other lamnid sharks, the shortfin mako has a heat exchange circulatory system that allows the shark to be 7-10°F (4-7°C) warmer than the surrounding water. This system enables makos to maintain at a stable, very high level of activity, giving it an advantage over its cold-blooded prey.
Behavior
The shortfin mako's speed has been recorded at with bursts of up to . They can leap approximate high or higher in the air. Some scientists suggest that the
biochemistry of shortfin mako can swim up to . Scientists are in debate exactly how fast the shortfin mako shark can swim, as well as which particular species are actually the champion ocean swimmers. This high-leaping fish is sought as
game worldwide. There are cases when an angry mako jumped into a boat after having been hooked.
This shark is highly migratory.
Life history
Reproduction
The shortfin mako shark is a yolk-sac
ovoviviparous shark, giving birth to live young. Developing embryos feed on unfertilized eggs in uterus during the 15 to 18 month
gestation period. This is called (
oophagy) (i.e. egg-eating). Shortfins do not engage in sibling cannibalism unlike the sand tiger shark (
Carcharias taurus). The 4 to 18 surviving young are born live in the late winter and early spring at a length of about . It is believed that females may rest for 18 months after birth before mating again. Last and Stevens (2009) report shortfin makos bear young on average every 3 years.
Lifespan
A landmark study by Natanson et al. (2006) has overturned previous highly inaccurate estimations of lifespan and sexual maturity in shortfin makos from the North Atlantic. Natanson et al. (2006) aged vertebrae of 258 specimens and recorded:
Maximum age of 29 years in males (260 cm FL)
Maximum age of 32 years in females (335 cm FL)
50% sexual maturity at 8 years in males (185 cm FL)
50% sexual maturity at 18 years in females (275 cm FL)
Last and Stevens (2009) report similar findings.
Captivity
Of all recorded attempts to keep
pelagic shark species in
captivity, the shortfin mako has fared the poorest; even more so than the
oceanic whitetip shark, the
blue shark and the
great white shark. The current record is held by a specimen that, in 2001, was kept at the
New Jersey Aquarium for only five days. Like past attempts at keeping
Isurus in captivity, the animal appeared strong upon arrival but had trouble negotiating the walls of the aquarium, refused to feed, quickly weakened and expired.
Attacks on humans
ISAF statistics records thirteen unprovoked shortfin
attacks between 1580 and 2010, on humans, three fatal, along with twenty
boat attacks. Sharks can be attracted to spear fishermen carrying a stuck fish, and may slap them with
cavitation bubbles from a swift tail flick. Though, generally these species of sharks will not attack humans. When humans are attacked, it is because they are mistaken for weakened or hurt prey.
In popular culture
The character Chum from Finding Nemo is a short-fin mako.
A mako shark appeared in Ernest Hemingway's novella, The Old Man and the Sea.
Three impossibly large short-fin mako sharks appear as the antagonists in the film Deep Blue Sea. Each one is approximately 23 feet in length and weighs around 8,000 pounds, a size that no mako has ever come closer to attaining. Shown using animatronics and CGI, the three sharks are genetically engineered to be intelligent, and in one case, extremely large. They destroy the facility they are housed in and eat most of the scientists studying them, before they are eventually killed (each is killed as an homage to the death of a shark in the Jaws movies.) A 'tiger shark' is seen early in the film, but it is really a mako shark with fanciful stripes.
In the movie The Beach (film) a Mako Shark attacks Richard (DiCaprio), who eventually kills it with a hunting knife.
Mako is one of the protagonist in the 1986 animated TV series TigerSharks.
The Proprietor of the Mermaid Cafe in the manga series One Piece is a short fin mako shark mermaid.
See also
Notes
References
Database entry includes justification for why this species is near threatened
External links
ARKive - images and movies of the shortfin mako (Isurus oxyrinchus)
CANADA: Record Mako Shark Caught
Shortfin mako sharks can shoot through the ocean at up to 50 miles per hour, New Scientist, 7 November 2008
Category:Lamnidae
Category:Ovoviviparous fish
