Isurus oxyrinchus

Geographic Range

Shortfin mako sharks are panoceanic, being found in the Pacific, Atlantic, and Indian Oceans. Within the Pacific Ocean, shortfin makos are found in both the northern and southern hemispheres, along the coasts of North and South America (from the Aleutian Islands and southern California to Chile), from Primorskiy Kray in the Russian Federation to Austraila and New Zealand and in Indo-Pacific waters from East Africa to Hawaii. Within the Atlantic Ocean, shortfin makos are found from the Gulf of Maine to southern Brazil and Argentina, and from Norway to South Africa. This species is also found in the Mediterranean and Red Seas. These sharks can travel long distances and have been know to swim thousands of kilometers per month to seek prey or mates.

• Biogeographic Regions
• nearctic nearctic
  • native native
• palearctic palearctic
  • native native
• oriental oriental
  • native native
• ethiopian ethiopian
  • native native
• neotropical neotropical
  • native native
• australian australian
  • native native
• indian ocean
  • native native
• atlantic ocean atlantic ocean
  • native native
• pacific ocean pacific ocean
  • native native
• mediterranean sea
  • native native

• Other Geographic Terms
• cosmopolitan cosmopolitan

Habitat

Shortfin mako sharks are pelagic and are typically found in surface waters up to depths of 150 meters, though they have been found as deep as 740 meters. Although these sharks can be found in many regions, they prefer to inhabit tropical and temperate offshore waters with temperatures from 17-20°C; however they can survive in water as cold as 5-11°C, as they are able to conserve heat within their bodies rather than losing it through their gills.

• Habitat Regions
• temperate temperate
• tropical tropical
• saltwater or marine saltwater or marine

• Aquatic Biomes
• pelagic pelagic

Physical Description

Shortfin mako sharks typically range in length from 3.2 m to 3.8 m, with females being larger than males. Adult weight ranages between 60 to 135 kg (females may reach 150 kg). Shortfin mako sharks have cylindrically shaped bodies, similar to those of great white sharks ( Carcharodon carcharias ), and are streamlined, fast-moving creatures. Makos effectively and quickly propel themselves through water by using their vertically elongated, thick, powerful caudal fin. They have bluntly pointed snouts, long gill slits for obtaining oxygen, and black eyes. Body coloration is bright metallic blue dorsally and white ventrally (areas around the mouth and underneath the snout are also white), although each shark's colors vary slightly depending on age and size; juveniles have a black spot on the tip of their snouts. The teeth are large, conical and extremely sharp, projecting outside the mouth when it is closed. The pectoral fins are quite small (shorter than the length of the head).

• Other Physical Features
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Development

These sharks are ovoviviparous. Embryos develop, nourished by egg yolk in egg sacs, in their mother's uterus (there is no placental connection). Young hatch into the uterus and exhibit oophagy (more developed fetuses may cannibalize eggs and less developed siblings). While in utero, the teeth, organs, lateral line, and other important structures develop. After 15-18 months, a litter is born, ranging from 4-16 pups at an average size of 68-70 cm. Juveniles are independent and grow quickly at first, though sexual maturity is not achieved until at least 8 years of age for males and 18 years of age for females.

Reproduction

Little information on mating exists for this species, but as is the case for other lamnid sharks, breeding is promiscuous, with no pair bonds formed. This species shows marked sexual segregation in some areas; adult males and females are seldom found together, possibly caused by females avoiding of males due to potential reduced fitness. Courtship and mating are thought to take place during late summer and early fall and, judging from female scars, is quite violent, involving males biting females' bellies, flanks, gill regions and pectoral fins. There is some evidence that females return to birthing and nursery sites repeatedly, such as the Southern California Bight, Strait of Gibraltar, and the area between 17-35°S off the coast of Brazil.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Males and females of this species become sexually mature at different ages. Females reach maturity at about 3 meters in length (approximately 18 years of age) and males at approximately 2 meters in length (8 years of age). There is evidence that breeding takes place during late summer and early fall months. Gestation period ranges from 15-19 months and young are typically born during spring (May-June or November, depending on hemisphere). Young are born at an average length of about 70 cm; litters may range in size from 4-25 but not all survive to birth due to oophagy. After birth, females rest for 18 months before reproducing again, leading to a reproductive cycle length of 2-3 years.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• ovoviviparous ovoviviparous

Embryos and young develop inside females and are born resembling very small adults. Following birth, there is no further female parental investment. Males exhibit no parental investment.

• Parental Investment
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

Age is estimated using vertebral growth bands; although it was once held that two such bands were laid down each year, recent work has shown that only one band is produced per year. Therefore, average lifespan is now estimated at 29-32 years, twice what was once thought. Females tend to live longer than males. Makos do not tend to survive capture, and none have ever been born in captivity.

Behavior

Shortfin mako sharks are warm bodied and extremely active. They are fast, strong swimmers, capable of reaching speeds up to 32 km/hour, and are known to leap out of the water when hooked on a line. They can travel up to 55 kilometers per day and seem to follow warm waters within any given geographic area, though there is little evidence of large scale migrations. Some populations show signs of sexual segregation and, generally speaking, individuals are solitary. Unprovoked attacks on divers are rare because the sharks are found well offshore. They are, however, known to become aggressive around speared fish. These sharks spend most of their time in mixed layers, with infrequent excursions below the thermocline.

• Key Behaviors
• natatorial natatorial
• diurnal diurnal
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• nomadic nomadic
• migratory migratory
• solitary solitary

Home Range

This is a non-territorial, pelagic species. Little is known about the size of their home ranges.

Communication and Perception

Shortfin mako sharks are generally solitary; little is known specifically about how they may communicate with each other. These sharks have a well-developed sense of smell, with a pair of nares located underneath the snout. As water enters the nares, it passes over olfactory lamellae, which bear neurosensory cells. These sharks also have excellent eyesight; millions of rod cells, combined with a tapetum lucidum (to reflect light back into the retina) give them high light sensitivity and keen vision in low light conditions. They are also able to feel their way around their environments via tactile methods (nerve endings covering their skin, teeth, jaws and mouth). In addition, these sharks use their lateral line organs to sense changes in water pressure and movement. Shortfin mako sharks, like all chondrichthyans, have electrosensory organs known as Ampullae of Lorenzini which can be used to sense prey and possibly aid in navigation.

• Communication Channels
• visual visual
• tactile tactile
• chemical chemical
• electric electric

• Other Communication Modes
• vibrations vibrations

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical chemical
• electric electric

Food Habits

Shortfin mako sharks are at the top of the marine food chain, making them apex predators. Bluefish ( Pomatomus saltatrix ) have been shown to make up about 92% of their diet (by weight) in the northwest Atlantic. Generally, prey include other fish and elasmobranchs, cephalopods and, occasionally marine mammals. Recorded prey includes Atlantic mackerel ( Scomber scombrus ), Atlantic herring ( Clupea harengus ), albacore ( Thunnus alalunga ), swordfish ( Xiphias gladius ), squid ( Loligo pealeii and Illex illecebrosus ), dolphins ( Delphinus capensis ), green sea turtles ( Chelonia mydas ), and unidentified small cetaceans.

• Primary Diet
• carnivore carnivore
  • piscivore piscivore

• Animal Foods
• mammals
• fish
• mollusks

Predation

Shortfin mako sharks display pelagic countershading to conceal them from potential predators such as great white sharks and killer whales. Humans are probably the most frequent predator of these sharks.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Shortfin makos are a vital part of oceanic ecosystems. As top-level predators, they eat smaller predators, affecting populations of other prey organisms lower in the food chain. They also control spatial distributions of prey by switching prey when the supply of one becomes low, helping to maintain diversity in a given environment. They are known to have remoras associated with them, which help to keep populations of ectoparasitic copepods in check.

• Ecosystem Impact
• keystone species keystone species

Economic Importance for Humans: Positive

As one of the fastest sharks, shortfin mako sharks are desirable trophy fish. Additionally, their fins, flesh, and liver oil are sold in Asian markets.

• Positive Impacts
• food food
• source of medicine or drug source of medicine or drug

Economic Importance for Humans: Negative

According the to Global Shark Attack Directory, there have only been three reports of Shortfin mako attacks on humans since 1974, therefore it is not considered a great natural threat to humans. They are known to damage boats and fishers after being hooked.

• Negative Impacts
• injures humans
  • bites or stings

Conservation Status

The IUCN lists this species as vulnerable, with a decreasing population. This decrease can be directly linked to overfishing, as well as their presence in bycatch of albacore ( Thunnus alalunga ) and broadbill swordfish ( Xiphias gladius ). The U.S. National Marine Fisheries Service has included this species on their list of managed pelagic sharks and reduced the number of catches, both commercial and recreational, allowed per year in the U.S. and Gulf waters by 50% in the hope of protecting this species. However, other populations outside the authority of the USNMFS are still vulnerable.

Additional Links

Encyclopedia of Life

Contributors

Madison Bridge (author), San Diego Mesa College, Roderick Knighten (author), San Diego Mesa College, Sara Tullgren (author), San Diego Mesa College, Paul Detwiler (editor), San Diego Mesa College, Jeremy Wright (editor), University of Michigan-Ann Arbor.

References

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