Shortfin Mako, Isurus oxyrinchus
The Shortfin Mako, Isurus oxyrinchus, whose common Spanish name is mako, is a member of the Mackerel Shark or Lamnidae family, collectively known as jaquetones in Mexico. Globally, there are five species placed in three genera in the Lamnidae family, of which three species are found in Mexican waters, two in both the Atlantic and the Pacific and one in the Pacific.
The Shortfin Makos have powerful classic hydrodynamic elongated slender shark-like bodies with a conical pointed snout, a triangular dorsal fin, and a large crescent-shaped tail with a slender base. They are dark metallic blue dorsally and silver ventrally with a very distinct color break on their sides. The undersides of their snout are white. They have large black eyes and long sharp dagger-like teeth that protrude from their mouth. Their anal fin and second dorsal fins are very small; their caudal fin is crescent-shaped with the upper lobe being larger than the lower lobe and with strong lateral keels on each side of the base; their first dorsal fin originates over the pectoral fin border; and their pectoral fins are long and narrow.
The Shortfin Makos are found in the open ocean normally at depths between 95 and 190 feet but have also been recorded at depths of 2,425 feet. Juveniles can be found on occasion in inshore waters at depths of less than 150 feet. They reach a maximum of 3.8 meters (12.5 feet) in length and 570 kg (1,425 pounds) in weight with females being significantly larger than males. They are warm-blooded and can maintain their body temperature from 7oC (12.5oF) to 10oC (18oF) above the temperature of the surrounding sea. They are rapid swimmers reaching speeds of 20 mph making them the fastest shark in the ocean. They are apex predators that consume approximately 2.0 kg (4.4 pounds) of food per day feeding on a wide variety of fish including other sharks, rays, sea birds, turtles, marine mammals, squid, and benthic crustaceans. Juveniles are preyed upon by other sharks. Humans are the only known predators of adults. They make seasonal migrations to warmer waters preferring water temperatures between 17oC (63oF) and 20oC (68oF). They normally travel as solitary individuals and are capable of making long distance journeys with one individual being documented as traveling 2,130 km (1,320 miles) in 37 days. Reproduction is ovoviviparous with embryos developing in the uterus and being nourished by yolk stored in a yolk sac. When the young hatch in the uterus, cannibalism or oophagy occurs whereby the unfertilized or less developed eggs are consumed by the stronger fetus. They are slow growing with males reaching sexual maturity in 8 years and females in 18 years. Reproduction cycles last three years and include 15 to 18 month gestation periods. Litter sizes range from 8 to 25 pups with larger females giving birth to larger litters of larger individuals. Pups are 60 cm (24 inches) to 70 cm (28 inches) in length at birth. They have a lifespan of thirty years, however, very little is known about their behavioral patterns.
In Mexican waters the Shortfin Makos are found in all oceanic waters of the Atlantic and the Pacific.
The Shortfin Mako can be confused with the Blue Shark, Prionace glauca (first dorsal fin closer to pelvic fins than to pectoral fins), the Great White Shark, Carcharodon carcharias (semi-lunar tail with equal lobes), and the Longfin Mako, Isurus paucus (snout with dark underside; larger eyes; larger pectoral fins; absent in waters north of Acapulco).
The Shortfin Makos are considered one of the greatest gamefish in the world due to their beauty, aggressiveness, initial burst of speed with torpedo-like runs when hooked, and jumping ability where they breach to incredible heights. They are also a highly sought after commercial species being the most frequently caught shark primarily as a by-catch of the tuna and swordfish fisheries via hook and line, longlines, stationary gill nets, and drift nets. They are the most sought after shark species from a food perspective and are marketed fresh, frozen, smoked and dried salted, and at times sold as swordfish; their fins (for soup), liver oil (for vitamins), hides (for leather), and teeth (for ornamentals) are also sold commercially. They are caught on trolled baits and lures as well as with live or dead baits from anchored or drifting boats. Recently they have become the subject of ecotourism diving with sites in California, the Maldives, and South Africa. The Mako Shark was also the star of Ernest Hemingway’s The Old Man and the Sea. From a conservation perspective they are currently classified as Vulnerable with significantly declining global populations attributed to unregulated intense global fishing pressure with poorly reported catch levels as well as to their migratory nature and their exceedingly long reproductive cycle. Although attacks on humans are rare, due to their power, aggressiveness, teeth, and great speed, they are considered dangerous to humans and can become highly aggressive around spearfishermen who have speared prey. They have also been reported to attack the boats of anglers when hooked.
Shortfin Mako, Isurus oxyrinchus, Juvenile. Fish caught by the commercial fishermen of the greater Los Cabos area, Baja California Sur, April 2011. Length: 65 cm (26 inches).
Shortfin Mako, Isurus oxyrinchus. Fish caught from coastal waters off Todos Santos, Baja California Sur, July 2012. Catch and photo courtesy of the local commercial fishermen of Todos Santos. Length: 2.75 meters (9 feet 0 inches).
Shortfin Mako, Isurus oxyrinchus. Fish caught from coastal waters off Point Palmilla, Baja California Sur, December 2011. Length: 1.37 meters (4 feet 6 inches).
Shortfin Mako, Isurus oxyrinchus, Jaw. Provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, September 2009.