Basking shark
The basking shark is a gentle giant, known for its impressive size and docile nature. As the second-largest shark species, it can grow to lengths of 25 to 30 feet (about 8 meters) and weigh up to five tons. Despite its formidable appearance, the basking shark primarily feeds on tiny invertebrates and zooplankton, filtering them from the water through its wide-open mouth as it swims slowly near the ocean surface. This species is migratory, traveling through temperate oceans worldwide and often seen basking or lying still at the surface.
Basking sharks breed in coastal waters from May to July, with females producing a strikingly high number of eggs—approximately six million—though the reasons for this high output remain unclear. The young are born already measuring about five feet (1.5 meters) in length. Unfortunately, basking sharks face significant threats from human activities, including bycatch in fishing nets and exploitation for their meat and other products. Their average lifespan can reach up to 32 years, both in the wild and in captivity, highlighting their resilience as a species.
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Basking shark
The basking shark is a deceiving fish. While it has the large mouth and large dorsal fin of its ferocious relatives, it is a rather gentle shark. Contrary to what its size might suggest, the basking shark feeds on small sea creatures which it filters through its mouth. The basking shark receives its name from its habit of basking, or lying still, near the ocean surface.
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Isuriformes
Family: Cetorhinidae
Genus: Cetorhinus
Species: Maximus
The basking shark is a migratory species, meaning it relocates throughout temperate oceans across the world. It is the second-largest shark in the world, and the full-grown basking shark reaches a length of 25 to 30 feet (about eight meters). It can reach a weight of up to five tons (4 1/2 metric tons). Its skin is a deep blue to charcoal above and a paler variation of the color on its underbelly.
The basking shark's diet consists of tiny invertebrates and zooplankton. As it moves through the water, it opens its mouth wide, allowing the water to filter through its mouth and gills. From the water, the shark obtains oxygen as well as food in the form of plankton. The water passes over gill rakers which, as their name suggests, rake the water. The rakers contain sticky bristles which trap the food, allowing the water and carbon dioxide to pass out of gill slits on either side of the mouth.
Despite its size, the basking shark is a docile, lethargic animal. It moves slowly through the water, never reaching speeds above three miles (five kilometers) per hour. Its name is appropriate as the fish is often seen lying still, or basking, at the water's surface. Although most commonly seen alone or in pairs, the basking sharks often congregate in schools of 50 to 100.
Basking sharks breed in coastal, shallow waters between May and July. Their egg production is markedly different from that of most sharks. Most sharks produce a small number of large eggs. The female basking shark, however, produces about six million eggs roughly 1/5 of one inch (1/2 centimeter) in diameter. As with most sharks, fertilization is internal, and the young develops within the mother's body. It is unclear why the female develops such a large number of eggs. Some believe the unfertilized eggs may provide nourishment to the developing embryos.
When born, the basking shark is already five feet (1 1/2 meters) long. The basking shark is considered sexually mature at 15 to 20 feet (4 1/2 to 6 meters) in length.
The greatest threat to basking sharks is humans. Fisheries around the world by-catch them in trawl nets. The shark has also been used by humans in many ways commercially, such as for bait, fishmeal, leather, and oil.
The average life span of the basking shark is as high as 32 years in both the wild and captivity.
Bibliography
Bauernfeind, Melissa. “Basking Shark.” A-Z Animals, 24 Mar. 2023, a-z-animals.com/animals/basking-shark/. Accessed 22 Mar. 2024.
Powell, Logan. “Cetorhinus Maximus (Basking Shark).” Animal Diversity Web, animaldiversity.org/accounts/Cetorhinus‗maximus/. Accessed 22 Mar. 2024.