The shortfin mako shark (Isurus oxyrinchus) is one of the most special and fascinating sharks in existence. This shark is a large mackerel shark belonging to the family Lamnidae. Other common names of this species include bonito shark, and the blue pointer.
This shark is one of the species under the genus Isurus. The second species is the longfin mako shark (Isurus paucus). Both make up the mako shark group with the shortfin mako occurring in all the temperate and tropical oceans of the world.
Shortfin makos hold the record as the fastest shark species existing today. They can reach a speed burst of up to 42 miles per hour (68 km/h). Their speed and unique appearance amongst other features make these sharks popular and attention-catching.
Origin of Their Names
The name mako is from the Māori language meaning “a shark tooth” or ” the shark tooth”. In line with the Māori language, “mako” represents both singular and plural. Constantine Rafinesque in 1908 gave the shortfin mako shark its scientific name Isurus oxyrinchus. Isurus means “the same tail” while oxyrinchus means “pointy snout”.
Physical Appearance of the Shortfin Mako
One of the most prominent distinguishing factors of the shortfin mako shark is its coloration. On the dorsal side, this shark has colors ranging from deep purple to bright indigo, metallic blue. This color graduates to silver at the sides, while the ventral side is white in color. The underparts of the snout and the mouth surrounding of this species also have white coloration. This type of coloration aids them in countershading, thus providing discreetness during hunting.
Shortfin mako sharks in addition to their distinctive coloration have a slender, elongated body shape. Their teeth are very sharp complementing their role as predators. The teeth of these sharks stand out from other sharks and help larger species in attacking large prey. Even while shortfin makos close their mouth, their teeth still stick out showing how dreadful they could be.
Other noticeable physical attributes of this species include the five large gill slits and their well-developed large eyes. The juveniles have clear blackish stain over the tip of their snout, which differentiates them from adults.
Fins
Fins as part of the physical characteristics of the shortfin mako shark cannot be overlooked, after all, it is part of the shark’s common name. Certainly, as the name implies, these sharks have very short fins compared to the body ratio. The second dorsal fin is noticeably shorter than the first one. Also, their pectoral fins are shorter compared to the sister species longfin mako shark.
Growth Size
Shortfin mako sharks are fairly large sharks. On average, they grow up to 10 feet (3.2m) in length. Interestingly, they grow faster than other species in the family Lamnidae. They exhibit sexual dimorphism in that the females tend to grow larger than the males. However, a male shortfin mako would reach sexual maturity at the length of 6.6 ft (2 m), while the female counterpart would do so at 8.2 ft (2.5 m).
Some large female shortfin mako has been recorded to grow a length above 12 ft (3.8 m), while also exceeding the weight of 1,260 lb (570 kg). The maximum recorded length of this species is 14.6 ft (4.45 m).
On the other hand, the highest recorded weight is 1,300 lb (600 kg). A specimen caught on hook-and-line off the coast of California.
Where to Find Shortfin Mako Sharks
Shortfin mako sharks are deep water dwellers inhabiting both the tropical and temperate oceans all over the world. These sharks mostly swim the offshore waters, however, as very active species, they occasionally come close to shore, around islands and inlets.
These species occur from the surface to depths up to 490 feet (150m). They have remarkable swimming and driving characteristics. Shortfin mako sharks are endothermic and can maintain a body temperature warmer than their surrounding environment. There are very few sharks with such qualities. As a result, they can stay anywhere in the world except of course, in very cold waters with temperatures below 61°F (16°C).
Distribution Range
Occurring in the western Atlantic, these species have been found from Argentina to the Gulf of Mexico to Browns Bank which is off of Nova Scotia. They also occur in the Pacific Ocean, seen from the United States to Chile. In the Canadian waters, shortfin makos are neither scarce nor abundant.
The presence of swordfish can also suggest the population of shortfin mako sharks. Swordfish are a source of food to the shortfin mako and prefer similar environmental conditions.
This shark species has a special preference for waters surrounding southern California with particular emphasis on San Diego. During the summer season, individuals mostly found in this area are juveniles. As a result, some researchers believe that female shortfin mako sharks travel to the area when it time to give birth.
A female shortfin mako originally tagged off California in 1998 was later captured by a Japanese research vessel in the central Pacific. This and other instances prove that these sharks are long-distance travelers.
Hunting and Feeding Behaviors
Shortfin mako sharks are predators, in fact, they feed at the top of the food chain in their ecosystem. In other words, they are apex predators with no species particularly preying upon them.
They tend to swim below their prey when hunting. The essence is to see what is above and secure a higher chance of reaching the prey before it notices. They attack by lunging upwards vertically and tearing off chunks of flesh from the flanks and fins of their prey.
Shortfin mako sharks like most other sharks take advantage of the vulnerability of their prey to hunt them down. For example, they tend to hunt swordfish during late spring and early summer. This period corresponds to the spawning cycle of the swordfish, thus, they are more vulnerable at this season. Shortfin mako has been found in Ganziri and Isola Lipari Sicily with amputated swordfish bills pierced through their head and gills. This suggests that swordfish can seriously injure and possibly kill shortfin mako sharks.
Major Sources of Food
The main source of food for shortfin makos are cephalopods and bony fish which includes tunas, mackerels, swordfish, and bonitos. However, these are not their only source of food. They also feed on other sharks such as blue shark, squids, sea turtles, porpoises, dolphins, and sea birds.
Some prey such as dolphins and swordfish are mostly for larger shortfin makos. This is because larger individuals have considerably wider and flatter interior teeth than smaller ones. It takes shortfin makos a day and a half or two to digest an average-sized meal.
The endothermic circulatory system of this species gives them an advantage over their cold-blooded prey. Certainly, they can maintain a temperature of about 7 to 10°F warmer than their surrounding environment. This enables the shortfin mako a higher level of activity over its prey.
Typical Behavior of Shortfin Makos
Shortfin mako sharks are the fastest sharks in the ocean. In fact, no other species can swim like these sharks. They are unbelievably fast with an estimated normal speed of 25 miles per hour (40 km/h), and a burst of up to 46 miles per hour (74 km/h). With such speed, these sharks can undoubtedly travel very long distances within a short time. Thus, they have been known to travel in a little over a month as far as 1300 miles (2,092 km).
The speed of shortfin makos allows them to jump to heights up to 30 feet (9 m) out of water in a practice known as breaching. There are reports of shortfin makos jumping into a boat after being hooked. These characteristics make them highly sought-after as game fish.
Threat Display
Divers who encountered shortfin mako sharks noted that before an attack, they usually swim in a figure-8 pattern while approaching with an open mouth. Threat display is common among some species of reef sharks.
Brain Size and Intelligence
Another striking characteristic of the shortfin mako shark is the large brain size. As a matter of fact, this shark among all studied shark species has one of the largest brains compared to body size. And, it is this large brain to body ratio that leads to the investigation of the intelligence of shortfin makos.
The researchers tested the shortfin mako on shape differentiation, electroreception, and individual recognition. In summary, the result proved that shortfin makos are fast learners. They were also able to decipher whether or not the researchers were a threat or not.
Each different specimen involved in the research showed a unique novel behavior afterward. For example, refusing to roll back the eyes while feeding and ignoring brief restraints and touching while being offered bait.
Another finding is that shortfin makos do not rely on electroception to hunt down their prey. Instead, they use mostly their vision supported by smell and hearing. This was discovered while testing the sharks on electroreception using wired fiberglass fish designed to emit weak electrical signals just like a real fish of similar size.
A 1999 documentary presented by shark week called “Mako: Swift, Smart, and Deadly”, featured the results this research on shortfin makos.
Life Cycle of Shortfin Makos
Reproductive Behavior
Shortfin mako sharks are ovoviviparous species, or otherwise known as aplacental viviparous. This implies that the embryos develop within eggs and hatch inside the body of the female, before being birth alive. The embryos get nourishment from a yolk sac as the eggs are kept in the same brood chamber in which the embryos develop.
Developing embryos feed on unfertilized eggs which is a process known as oophagy. However, they do not participate in sibling cannibalism as found in the sand tiger shark (Carcharias taurus)*. Male shortfin makos reach sexual maturity at about 6.6 feet (2 m) length, while females do so at 8.2 feet (2.5 m).
Gestation Period and Parturition
Gestation in shortfin makos lasts for 15 to 18 months. Birthing occurs in the late winter and early spring with females producing 4 to 18 surviving pups. At birth, these pups measure about 28 inches (70 cm) in length.
After giving birth, the females tend to rest for about 18 months before mating again. With this, it takes an average of 3 years for shortfin makos to reproduce.
Lifespan
Determining the age of shortfin makos involves a similar process of counting growth bands through sectioning of vertebrae used in other sharks. The vertebrae are surely one of the few bony structures in sharks. Initially, it was thought that the shortfin mako deposited two growth bands yearly in their vertebrae. This leads to the underestimation of their age and other important parameters such as the age of sexual maturity, and lifespan.
A landmark study overturned this belief while proving that shortfin mako sharks deposited only one growth band each year in their vertebrae. Hence, the research provided validated ages for numerous specimens.
- Male shortfin makos recorded a maximum age of 29 years with the average sexual maturity age of 8 years.
- Females, on the other hand, recorded a maximum age of 32 years with an average sexual maturity age of 18 years.
Human Interaction
Attacks on Humans
This is one of the ways sharks may encounter humans. The ISAF as of 2017 listed nine direct attacks on humans attributed to the shortfin mako shark. Only one out of these attacks was fatal. Along with this are 20 boat attacks which usually occur as a result of shortfin makos trying to steal captured prey from fishermen on the boat.
Shortfin makos regularly take the blame for several attacks on humans due to their speed, size, and high level of activity. Of course, they certainly can inflict fatal injuries on humans. However, it is worthy to note that these sharks do not prey on humans. Thus, they rarely develop an interest in humans. This means that they would not attack humans except if provoked.
Recent attacks on humans by this species are attributed to them being provoked, either by harassing or catching them on the fishing line. Shortfin mako sharks may through swift tail-flick slap fishermen carrying a stuck fish with cavitation bubbles.
Shortfin Makos in Captivity
Humans capture shortfin mako sharks in an attempt to keep them in captivity. But, these sharks have fared the poorest in captivity more than any other pelagic shark species. The highest number of days in captivity recorded of any shortfin mako is five days, held by an individual kept at the New Jersey Aquarium in 2001.
All attempts to keep this species in an aquarium failed following a similar pattern. That is, they appear strong when first introduced, then there is the difficulty negotiating aquarium walls, failure to feed, gets weak quickly and eventually dies.
Shortfin makos cannot withstand aquarium conditions. Even the great white shark (Carcharodon carcharias), the blue shark, and the oceanic whitetip shark fared better than them.
Fishing for Sport
Shortfin makos are extremely fast species and can perform fast runs, acrobatic flips, and heavy fights which serve as entertainment to anglers. Fishing shortfin makos for sport is a predominant activity around the world.
The traditional method of fishing is usually hooking them using chum and bait casters. But, fly fishing is now more popular in fishing makos, especially in San Diego. San Diego is host to one of the three known mako rookeries in the world.
Mass commercial boats hunted the shortfin mako for several years. However, with the efforts of many national organizations and local fishing companies, there is control now over this activity.
Conservation
Conservation Status
The International Union for Conservation of Nature (IUCN), currently listed the (Isurus oxyrinchus) as “Endangered (EN)”. This was after uplifting it from Vulnerable in 2019.
Threats
Human activities especially fishing for commercial and sports activities serves as major threats to this species. There is also considerable bycatch in driftnets set for other species. These activities pose a threat to the population of shortfin mako sharks and are the cause of the current depletion in their numbers.
Conservation Actions
Following the rapid depletion of the shortfin mako shark population, some regions where it occurs are now putting efforts to conserve this species. For example, there are the U.S National Marine Fisheries Service (NMFS) regulations put in place to protect these sharks in the United States’ Gulf and Atlantic waters.
The NMFS reduced the allowed shortfin mako sharks catch per year by 50%. This is a good start, but these laws apply only in the United States. Though there are other regulations, we still hope more actions would be taken to better conserve this species worldwide.
Interesting Shortfin Mako Shark Facts at a Glance
1. The Shortfin Mako is the Fastest Known Shark in the World
With a normal speed of 25 mph (40 km/h) and a burst of up to 46 mph (74 km/h), this shark proves to be the fastest swimmer among all sharks. As a result, they can cover a very long distance within a short time.
2. They Can Leap to Heights of up to 30 feet
This species’ speed enables it to launch a vertical motion from which it can jump as high as 30 ft (9 m) out of water. This is certainly extraordinary.
3. Shortfin Makos are Intelligent Species
This shark is among the sharks with the largest brain to body ratio among all examined sharks. As a result, a test for intelligence was conducted and the result showed they can reason and perform certain social behaviors other sharks cannot. Hence, they can even identify if an approaching diver poses a threat or not.
4. These Sharks are Endothermic
Shortfin makos are among the very few endothermic sharks. Thus, they can maintain a body temperature warmer than the surrounding water. This increases their level of activity more than their cold-blooded counterparts.
5. Mako Sharks Needs to Swim to Survive
As obligate ram ventilators, they survive by trapping oxygen as water constantly rush over their gills. Therefore, if they ever stop swimming, they would die. They only have periods of inactivity when they regain their energy and does not sleep.
6. This Species is a Highly Sought-after Game Fish
Due to their high activity level, speed, and power, recreational fisheries catch the shortfin mako for entertainment. They engage in fast runs, fights, and acrobatic flips to entertain anglers.
7. They are the Least Pelagic Shark Species to Survive Captivity
Shortfin makos do not do well in captivity. In fact, the record for the highest number of days in captivity is just five days.
8. Shortfin Makos are Active Hunters
These predators actively hunt down their prey by lunging upwards against them. They also take advantage of their prey’s vulnerability to attack them.
9. They do not Rely on Electroreception to Track Prey
Shortfin makos use mainly their vision, smell, and hearing to track and hunt their prey. Hence, weak artificial electrical signals do not attract them.
10. Reproduction Takes an Average of Three Years
With the gestation period of about 15 to 18 months and the females resting for another 18 months before mating again, the reproductive cycle takes around 3 years.
11. They Prefer a Meal of Swordfish
Shortfin makos prefer to prey on swordfish. They usually attack swordfish during their mating season when they are most vulnerable. Although hunting swordfish is not as easy as they (shortfin makos) sometimes sustain fatal injury from the swordfish bill, they still prey upon them.
12. Shortfin Mako Sharks (Isurus oxyrinchus) is Now an Endangered Species
The IUCN currently listed this species as Endangered after uplifting it from Vulnerable in 2019. The major threat to their population is fishing by humans.
Further Reading
- “Shortfin mako sharks, Isurus oxyrinchus“, MarineBio.
- “Isurus oxyrinchus“, Shark references.
- “Shortfin mako (Isurus oxyrinchus)“, IUCN Red List of Threatened Species.
- “Discover Fishes: Shortfin mako (Isurus oxyrinchus)“, Florida Museum.
- “Atlantic Shortfin Mako Shark”, NOAA Fisheries.