Shortfin mako shark

A shortfin mako shark

The shortfin mako inhabits offshore temperate and tropical seas worldwide.[15] The closely related longfin mako shark is found in the Gulf Stream or warmer offshore waters (e.g. New Zealand and Maine).

It is a pelagic species that can be found from the surface to depths of 150 m (490 ft),[16] normally far from land, though occasionally closer to shore, around islands or inlets.[17] One of the very few known endothermic sharks, it is seldom found in waters colder than 16 °C (61 °F).[18]

In the western Atlantic, it can be found from Argentina and the Gulf of Mexico to Browns Bank off of Nova Scotia.[16] In Canadian waters, these sharks are neither abundant nor rare. Swordfish are good indicators of shortfin mako populations, as the former are a source of food and prefer similar environmental conditions.[19]

Shortfin mako sharks 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 2,776 km (1,725 mi). Another specimen swam 2,128 km (1,322 mi) in 37 days, averaging 58 km (36 mi) a day.[20]

The head of a mako shark

The shortfin mako shark feeds mainly upon cephalopods and bony fish including mackerels, tunas, bonitos, and swordfish, but it may also eat other sharks, porpoises, sea turtles, and seabirds. They hunt by lunging vertically up and tearing off chunks of their preys' flanks and fins. Mako swim below their prey, so they can see what is above and have a high probability of reaching prey before it notices them. In Ganzirri and Isola Lipari, Sicily, shortfin mako have been found with amputated swordfish bills impaled into their head and gills, suggesting swordfish seriously injure and likely kill them. In addition, this location, and the late spring and early summer timing, corresponding to the swordfish's spawning cycle, suggests they hunt while the swordfish are most vulnerable, typical of many predators.[17]

Shortfin mako sharks consume 3% of their weight each day and take about 1.5–2.0 days to digest an average-sized meal. By comparison, the sandbar shark, an inactive species, 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 67–328 cm (26–129 in) suggest mako from Cape Hatteras to the Grand Banks prefer bluefish, constituting 77.5% of their diet by volume. The average capacity of the stomach was 10% of the total weight. Shortfin mako sharks consumed 4.3% to 14.5% of the available bluefish between Cape Hatteras and Georges Bank.[21]

Shortfin mako sharks over 3 m (9.8 ft) have interior teeth considerably wider and flatter than smaller mako, which enables them to prey effectively upon dolphins, swordfish, and other sharks.[20] An amateur videotape, taken in Pacific waters, shows a moribund pantropical spotted dolphin whose tail was almost completely severed being circled by a shortfin mako. Mako also tend to scavenge long-lined and netted fish.[22]

The bite of a shortfin mako shark is exceptionally strong; the current record for the strongest bite measured for any shark belongs to a shortfin mako that was recorded at Mayor Island in New Zealand in 2020. The shark had been coaxed into biting a custom-made "bite meter" as part of an experiment to measure mako bite force. The strongest bite recorded during the experiment was roughly 3,000 lbs. of force, or roughly 13,000 newtons.[23]

Its endothermic constitution partly accounts for its relatively great speed.[24]

Like other lamnid sharks, the shortfin mako shark has a heat-exchange circulatory system that allows the shark to be 4–5.5 °C (7–10 °F) warmer than the surrounding water. This system enables them to maintain a stable, very high level of activity,[25] giving it an advantage over its cold-blooded prey.[26]

The shortfin mako is a fast species that can leap into the air when hooked, making it a highly sought-after game fish worldwide. Some cases of shortfin mako jumping into a boat after having been hooked have been reported.[27]

The shortfin mako shark is a yolk-sac ovoviviparous shark giving birth to live young. Developing embryos feed on unfertilized eggs (oophagy) within the uterus during the 15- to 18-month gestation period. They do not engage in sibling cannibalism unlike the sand tiger shark (Carcharias taurus). The four to 18 surviving young are born live in the late winter and early spring at a length of about 70 cm (28 in). Females may rest for 18 months after birth before mating again. Shortfin mako sharks bear young on average every three years.[28] A common mating strategy of shortfin mako sharks has been documented as using multiple paternity as a mating strategy, known as polyandry. Polyandry is where the females mate with more than one male. This strategy is used to have a single brood sired by multiple males (multiple paternity) and is a common strategy in diverse taxa, including invertebrates and vertebrates.[29]

Shortfin mako sharks, as with most other sharks, are aged by sectioning vertebrae – one of the few bony structures in sharks – and counting growth bands. The age of shortfin mako, and therefore important parameters, such as age at sexual maturity and longevity, were severely underestimated until 2006 (e.g. claims of sexual maturity at 4–6 years, claims of longevity as low as 11 years), because of a poorly supported belief that shortfin mako sharks deposited two growth bands per year in their vertebrae. This belief was overturned by a landmark study which proved that shortfin mako sharks only deposit one band in their vertebrae per year, as well as providing validated ages for numerous specimens.[30] Natanson et al. (2006) aged 258 shortfin mako specimens and recorded:

• Maximum age of 29 years in males (260 cm or 8.5 ft fork length (FL))
• Maximum age of 32 years in females (335 cm or 10.99 ft FL)
• 50% sexual maturity at 8 years in males (185 cm or 6.07 ft FL)
• 50% sexual maturity at 18 years in females (275 cm or 9.02 ft FL)

Similar, validated age findings were made (median age at maturity in males 7–9 years, median age at maturity in females 19–21 years, longevity estimates 29 years and 28 years respectively) in New Zealand waters.[31]

Due to this error, fishery management models and ecological risk assessment models in use around the world were underestimating both the longevity and the age at sexual maturity in shortfin mako sharks, particularly in females, by two-thirds or more (i.e. 6 years versus 18+ years), and some of these inaccurate models remain in use.

Of all studied sharks, the shortfin mako has one of the largest brain-to-body ratios. This large brain size prompted New Zealand Sealife Australia and New Zealand senior curator Craig Thorburn of Auckland, New Zealand, and film-maker Mike Bhana to investigate the intelligence of the shortfin mako. From tests involving shape differentiation to electroreception tests and individual recognition, Isuru Somawardana and his team of shark experts discovered shortfin mako are fast-learning sharks, able to determine whether or not the researchers were threatening. The sharks involved in the study (while never the same individuals) after initial caution showed unique and novel behaviors, such as refusing to roll back their eyes during feeding and allowing themselves to be briefly restrained and touched while being offered bait. Shortfin mako also do not rely on electroreception when hunting, unlike the great white shark, based on tests involving wired fiberglass fish designed to emit weak electrical signals resembling real fish of similar size. Instead, they rely on smell, hearing, and most prominently, vision. The results of this research were featured on a documentary presented by Shark Week in 1999 called Mako: Swift, Smart & Deadly.[32]

Mako fishing is a prominent activity around the world. As one of the fastest species in the water they offer acrobatic flips, fast runs, and heavy fights that entertain anglers. Traditionally, the sharks are hooked through the use of chum and baitcasters; however, fly fishing for them has become more popular, particularly in San Diego, where one of the three known worldwide mako rookeries is located. A cottage industry of fishing in this rookery has emerged, specifically catch and release with charter operations out of Mission Bay.[33] For many years the mass commercial boats hunted them for restaurant catch, but through the efforts of many local fishing companies and national organizations such as Orvis, this has been curbed.[34]

Shortfin mako shark that was captive for a short time at Yokohama Hakkeijima Sea Paradise

Of all recorded attempts to keep pelagic shark species in captivity, the shortfin mako shark has fared the poorest, even more so than the oceanic whitetip shark, the blue shark, and the great white shark. At SeaWorld San Diego, a 90 cm (3.0 ft) shortfin mako shark ability test failed in the early 1970s.[35] In the summer of 1978, two mako sharks caught off the coast of San Diego failed to evade the wall and both died within three days.[35] The current record is held by a specimen kept at the New Jersey Aquarium for only five days in 2001. Like past attempts at keeping Isurus in captivity, the animal appeared strong on arrival, but had trouble negotiating the walls of the aquarium, refused to feed, quickly weakened, and died.[36]

ISAF statistics records 9 shortfin attacks on humans between 1580 and 2022, three of which were fatal, along with 20 boat attacks.[37] This mako is regularly blamed for attacks on humans and, due to its speed, power, and size, it is certainly capable of injuring and killing people. However, this species will not generally attack humans and does not seem to treat them as prey. Most modern attacks involving shortfin mako sharks are considered to have been provoked due to harassment or the shark being caught on a fishing line.[38] Sharks can be attracted to spear fishermen carrying a stuck fish, and may slap them with cavitation bubbles from a swift tail flick. Divers who have encountered shortfin mako note, prior to an attack, they swim in a figure-eight pattern and approach with mouths open.[38]