Great White Shark, Carcharondon carcharias
Great White Shark, Carcharondon carcharias. Underwater photograph taken in coastal waters off Isla Guadalupe, Baja California Sur, September 2007. Photographs and identifications courtesy of Ken Bondy, West Hills, California.
The Great White Shark, Carcharondon carcharias, is a member of the Mackerel Shark or Lamnidae Family, that is also known as the White Shark and in Mexico as tiburón blanco. It is one of the best known sharks in the world. Globally, there are five species in the Lamnidae Family that have been placed in three genera, of which three are found in Mexican waters, two in both the Atlantic and the Pacific and one, this species, in the Pacific Ocean. The Great White Shark is considered by many to be the most powerful and most dangerous predatory sharks in the world and has been a focus of the scientific community with major studies done on lifestyle, evolution, and their strong immune system as they are capable of surviving with high levels of arsenic, lead and mercury in their tissues. It starred as the villain of the movie JAWS and is much maligned and publicly feared. They are closely related to the Mako Sharks but unrelated to the Mega-toothed Sharks.
The Great White Shark has a huge, spindle-shaped fusiform body. They are a lead-gray color shading to brown or black dorsally, lighter in the sides and transitioning abruptly to white ventrally. They have a black spot at the rear of the pectoral fin base. The iris of their eyes is a deep blue. Their head has conspicuous eyes, a robust, large, conical snout, long gill slits, and large, triangular, large, erect, triangular serrated teeth that are designed to cut flesh and can easily puncture and shatter bones. Their anal fin is very small and originates at the rear of the second dorsal fin; their caudal fin is crescent shaped with equally sized lobes and a single keel on the peduncle; their first dorsal fin is large and triangular and originates over the pectoral fin; their second dorsal fin in minute; and, their pectoral fins are large. Their skin is smooth to the touch.
The Great White Shark is a pelagic, oceanodromous non-schooling species that is found as solitary individuals, in pairs, or in feeding aggregations at depths up to 1,200 m (3,900 feet) in water temperatures between 12oC (54oF) and 24oC (75oF). They are common being found primarily in shallower coastal temperate and offshore waters of the continental and insular shelves near the surface around oceanic islands that have large populations of seals, and sea lions. They are rarely found in tropical waters. They reach a maximum of 6.4 m (21 feet 0 inches) in length, with females being larger than males, making it the fourth longest cartilaginous fishes currently alive and 2,268 kg (5,000 lbs) in weight. As of January 1, 2023, the International Game Fish Association world record stood at 1,208 kg (2,664 lbs)
with the fish caught in coastal waters off Australia, April, 1959. White Sharks have a complex circulatory system that conserves heat generated through the contraction of their swimming muscles and can maintain certain parts of their body at temperatures up to 14oC (25oF) above the temperature of the surrounding sea making them a text book example of giganotothermy and thus they are endothermic, poikilotherm and mesotherm because their body temperature is thermally regulated and is not constant. They are stealth lie-in-wait ambush predators that have a competitive advantage over other sharks that cannot regulate their body temperatures above the water temperature. They are considered to be the world’s largest apex predator that frequent waters that have an abundance of fishes and marine mammals. They feed during daylight hours and consume primarily pinnipeds (sea lions and seals) and a variety of fish, benthic crustaceans, marine mammals, rays, other sharks, and sea turtles. They possess an extraordinary sense that allows them to detect the electromagnetic field emitted by the movement of living animals, good eyesight, and a keen sense of smell. They can consume up to 14 kg (31 pounds) in a single bite and several hundreds of kg of food per day. They are known for the their slow and steady stealth ascent from the deep and the rapid generation of explosive speed, being capable of reaching 25 km per hour (16 mph) for short bursts, and breeching when attacking pinnipeds from below. Juveniles are preyed upon by other sharks. The adults have very few predators with the exception of the Killer Whales, Orcinus orca, and Humans. They are known to make long seasonal migrations which is attributed to seasonal feeding and mating. They are also known to make vertical Diehl Migrations spending daytime hours at depths of 450 meters and coming to the surface at night. They are considered to be intelligent and inquisitive and exhibit complex social behaviors. They are capable of making transoceanic migrations. Reproduction involves internal fertilization and is ovoviviparous with embryos developing in the uterus and being nourished by yolk stored in a yolk sac. Liter sizes vary from 7 to 14 pups that measure between 1.2 m (3 feet 11 inches) and 1.5 m (4 feet 11 inches) in length. 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, averaging 25 cm (10 inches) per year, with males reaching sexual maturity in 26 years and females in 33 years. Reproduction cycles last two or three years and include 11-month gestation periods. They have a lifespan of up to seventy years. As they cannot be maintained in captivity very little is known about the biology of the Great White Shark.
The Great White Shark is a resident of Mexican oceanic waters of the Pacific Ocean but has a limited range being found along the west coast of the mainland north of Mazatlán, Sinaloa, throughout the Sea of Cortez and along the west coast of the Baja.
The Great White Shark can be confused with the Longfin Mako, Isurus paucus (upper caudal lobe larger than lower lobe; lacks the abrupt color change to white ventrally), the Ragged-tooth Shark, Odontaspis ferox (large second dorsal fin), and the Shortfin Mako, Isurus oxyrinchus (anal fin originates under the center of the second dorsal fin; lacks the abrupt color change to white ventrally).
From a conservation perspective the Great White Shark is currently considered to be Vulnerable with significantly declining global populations based on catch rates which is attributed to long reproductive cycles with low litter sizes and unregulated intense global fishing pressure with poorly reported catch levels. In some areas they have been fished to near extinction. Their true global populations are difficult to assess but they are considered to be rare. They have been the focus of significant global conservations efforts lately. They are hunted by humans for food which includes finning for use of their fins in shark fin soup. They are also a highly prized sport fish. They are a major component of the taxidermy trade. The teeth are sought after my collectors and utilized in jewelry, their jaws from large individuals can be sold for several thousand dollars, their skin is utilized for leather, their liver for oil, the carcass for fishmeal. They are caught in high numbers as a by-catch of other commercial netting fisheries. They have been credited with more fatal attacks on human, that average 10 per year globally, than any other species of sharks. Unprovoked attacks on swimmers, divers, surfers, kayakers, and small boats have been well documented but thought to be a case of mistaken identity mistaking humans for natural prey (seals and sea lions), sample dining or simply curiosity. After sampling humans they generally reject them for food as they too many bones for their digestive systems. They have been dated to the middle of the Miocene Epoch (23 million to 5.3 million years ago).