Close cousins of the great white, shortfin mako sharks (Isurus oxyrinchus) are known to be the fastest shark species in the world. With their pointed snout, crescent-shaped tail fin, and triangular dorsal fin, shortfin makos can reach speeds of up to 43 miles per hour.
Biology & Anatomy
Ranging from 3.2m-3.8m (or 10.5ft-12.5ft) and 60kg to 135kg (132lb to 298lb), mako sharks have the ideal, conic-cylindrical build for gliding quickly through the water. They have a vertically long, thick, and powerful caudal (or tail) fin, along with very pointed snouts, which allows them to soar through the water. The high aspect ratio of their tail produces a high amount of thrust with minimal drag, allowing them to quickly propel themselves.
Body coloration is typically a metallic blue top, or dorsal, area and a white ventral, or bottom, area, though coloration is dependent on age & size. The snout and mouth area are also white on shortfin makos, which a key factor in differentiating them from the longfin mako (Isurus paucus), which have a more dark mouth and snout. Juvenile mako sharks have a distinct black spot on the tip of their snouts.
Shortfin makos have a U-shaped mouth and long, narrow, triangular teeth. Their teeth are almost hook-like with razor-sharp, non-serrated edges. Teeth of the lower jaw are visible even when their mouth is closed, and the upper jaw teeth are typically only visible when the upper jaw is protruded outwards, in most cases when biting.
Behavior
Not much is known about shortfin makos behavior. There have been some attacks by the mako, but very few considering they are oceanic sharks, meaning they are found in deep waters and not close to shore. Some divers who have encountered the shortfin mako said they will swim in a figure 8 motion with their mouth open before an attack. They are also well known for damaging boats and injuring fishermen after being hooked.
There is little evidence of large-scale mako migrations, it seems they may separate sexually and tend to travel alone. Little is also known of their breeding habits, however, it is believed they mate similar to other lamnid sharks, promiscuously and without bonding, as males and females are hardly found together. Due to scars found on female makos, mating appears to be violent.
Lifespan
The age of shortfin makos is calculated by using vertebral growth bands, which it was once thought that two bands were laid down each year, but recent discoveries show that only one band is produced each year. This means makos live twice as long as once thought, with a lifespan of 29-32 years old.
Diet
Shortfin makos are at the top of the marine food chain making them apex predators. An estimated 92% of their diet consists of bluefish, but their prey can consist of other fish, cephalopods, and occasionally marine mammals. Known prey of the shortfin mako includes Atlantic mackerel, Atlantic herring, albacore, swordfish, squid, dolphins, green sea turtles, and other small, unidentified cetaceans.
Geography & Habitat
Shortfin makos are panoceanic, they are found in Pacific, Atlantic, and Indian waters. In the Pacific, makos are in the northern and southern hemispheres, from the Aleutian Islands in Alaska to Chile, and from Primorskiy Kray to Australia. In the Atlantic, they can be found from the Gulf of Maine to southern Brazil, as well as from Norway to South Africa, and from South Africa to Australia in the Indian Ocean. They can also be found in the Red and Mediterranean Seas.
With their worldwide distribution, they mainly reside in oceanic waters, but occasionally can be found near coasts where the continental shelf is short. They reside in waters from the surface to about 500m (or 1640ft) deep, and in temperatures greater than 16°C (or 60°F). Though these are their typical ranges, they tend to stay in warm, tropical waters, and stay around 150m (or 492ft) deep.
Conservation
Shortfin makos are listed by the IUCN as a vulnerable species with a steadily decreasing population. The population decline is directly linked to overfishing, and being caught as bycatch. Mako sharks are heavily sought after in South East Asia for the use of shark fin soup and other illegal fish markets. The National Marine Fisheries Services has included shortfin makos on their managed pelagic sharks list to limit the amount allowed to be caught. However, due to the underreported catch data, as well as their large-scale geographical range, it is challenging to accurately obtain information on this species’ population.
Sources
Image Sources
https://www.telegraph.co.uk/news/2019/08/25/worlds-fastest-sharks-receive-un-protection-crackdown-fin-trade/
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