The oceanic whitetip shark () lives in tropical waters worldwide between north 45° and 43° south latitude. A globally widespread shark, they can be found in the Indian Ocean, the Atlantic Ocean, and the Pacific Ocean.
This shark migrates with the water currents, such as the Gulf Stream, during the summer seasons. Their migration routes includes the waters of Maine during the summer seasons, from the United States southward to Argentina in the western Atlantic Ocean. Their range also includes Portugal south to the Gulf of Guinea, which is a gulf of the northernmost part of the tropical Atlantic Ocean between Cape Lopez, Ghana and northwest to Cape Three Point in the western region of Ghana. They also travel east of the Atlantic Ocean to the Mediterranean during the winter season. Whitetips are also found in the Indo-Pacific region, which includes the Red Sea, East Africa to Hawaii, Tahiti, Samoa, and the Tuamotu Islands. Individuals have been tracked, travelling as much as 2,800 kilometers. (Dingerkus, 1999; Helfman and Burgess, 2014)
Oceanic whitetip sharks live in the pelagic zone of the ocean. On average, whitetip sharks swim at least 60 meters below the surface, but occasionally swim in shallower waters in to 35m deep. This species does not approach the ocean shore.
Some groups of whitetips are associated to specific geographical areas of reefs like the Great Barrier Reef. Oceanic whitetips are commonly found in habitats with a high vertical relief. Also, whitetips are found near abundant reef interstices, which are small crevices. Whitetips often hunt and rest in these interstices. (Dingerkus, 1999; Tricas, 1999)
Oceanic whitetips get their name from the white tips on the first dorsal, pectoral, caudal (upper and lower lobes), and pelvic fins. The dorsal side of their body can be a brown, grey, or grey-bronze color and the underside is white. This specific coloration creates a countershading effect. Countershading helps to blend into their surroundings and not to be detected by their potential prey.
Whitetips have long, broad fins with round edges. Their bodies are stocky with a short, blunt snout. Females are generally bigger than males with an average length of 3.9 meters with females weighing up to 170 kilograms. Males can reach up to 3 meters and weigh up to 167 kilograms. Oceanic whitetips feature a large pectoral fin, which allows them to glide through the water. The fin also adds stability to their movements, granting them agile bursts of speed. Like nearly all other sharks, whitetips have a heterocercal tail.
Newborns have black fin pigmentation, while the first dorsal fin has a tan or light brown tip. Generally, the newborns have black pigmentation on the fins, but eventually the black pigmentation fades into the shark’s natural white color on the tips of the fin. (Carwardine and Watterson, 2002; Dingerkus, 1999; Helfman and Burgess, 2014)
Oceanic whitetip sharks bear live young, providing the essential nutrients through a placenta in the uterine wall for the developing embryo process. Gestation time is 9 to 12 months. The embryos are attached by an umbilical cord that helps transfer nutrients and oxygen to the shark. Oceanic whitetips grow indeterminately.
In females, maturity stages are categorized as immature, mature, pre-ovulatory, and pregnant. Immature females have a filiform uteri and undeveloped ovaries. Mature females have large ovaries, a fully developed uterus, yolk follicles of various sizes, and oviducal glands, but the ovary is not yet near ovulation. Pre-ovulatory females have developed ovaries, with follicles ready to be in the ovulation stage. Indicating the ovulation stage, the oviducal glands are large because the glands are secreting hormones. Finally, pregnant females have a large and fully developed uterus containing the embryos.
Claspers and testes determine males’ maturity. There are three stages of maturity: juvenile, maturing, and mature. In the juvenile stage, claspers are not yet calcified and are smaller than the pelvic fin. The testes are small. Their enlarged testes are the identifying factor of maturing whitetips. The claspers of maturing males are still flexible, but are the same size or larger than the pelvic fin. The sperm ducts are developing. In the mature stage, the claspers are calcified, rigid, and larger than the pelvic fin. The testes are enlarged and the sperm ducts are tightly coiled. (Helfman and Burgess, 2014; Poey, 2011; Tambourgi, et al., 2013)
There isn't any documented information to describe the mating system of oceanic whitetips because of the difficulty of sampling. Oceanic whitetips could have similar mating systems as the sandbar species (Carcharhinus plumbeus) that exhibit genetic monogamy. (Daly-Engel, et al., 2007)
Oceanic whitetip sharks generally breed every two years during the early summer months. This typically takes place in the northwestern Atlantic Ocean and the southwestern Indian Ocean. Oceanic whitetips are viviparous. Both male and female become sexually mature at approximately six to seven years of age. The placenta provides the young nutrients during the gestations period of 9-12 months. The placenta is attached to the uterine wall by an umbilical cord. The mother produces a litter size averaging from 1 to 15 pups ranging from 60 to 65 cm. Research studies have recorded some newborns to having fresh umbilical scars, but not all of them have this trait. (Coelho, et al., 2009; Lessa, et al., 2011; Poey, 2011)
There is currently limited documentation to accurately explain oceanic whitetip parental involvement. Due to their viviparous reproduction, oceanic whitetip females provide provision and protection to their young, but only before birth. The mother provides nutrients and minerals, oxygen, and water for the developing embryo. Whitetips aren’t known to care for their young once after birth. Male whitetips aren’t known to care for newborns. ("2011 Nomination: Carcharhinus longimanus", 2011; Helfman and Burgess, 2014; Poey, 2011)
Oceanic whitetip sharks mature between six or seven years of age and their lifespan in the wild can reach 15 years. However, the longest known lifespan recorded in the wild is 22 years. (Garcia, et al., 2008)
Oceanic whitetips are solitary sharks, although some gather where food is available. However, if prey is accessible or a predator is nearby, the whitetips will exhibit a short burst of speed. Even though whitetips are solitary among sharks, pilot fish (Naucrates doctor), and dolphin fish (Coryphaena hippurus) will accompany them.
Whitetips are natatorial, capable of swimming long distances. Oceanic whitetips move from one location to the next throughout the year to search for food and warmer water. The whitetips’ swimming pace is slow because the pectoral fins are widely spread.
Oceanic whitetips have certain instances where the species is in a tonic immobility state. Tonic immobility is when the shark goes into a trance-like state and stops moving. This technique is demonstrated in scuba diving by placing a hand over their electroreceptors and rubbing their snout, which will temporarily stun the shark. Many researchers use this technique to calm the shark so they can measure or tag the whitetip, making it less likely to injure them.
Whitetips communicate through body markings, electric fields, and chemicals. Body markings are used to communicate with prey and with each other. The white-tipped fins may distract prey. The body markings make the oceanic whitetip appear larger and helps establish a social hierarchy within the species.
Whitetips detect electric fields of their prey by the use of electroreceptor organs on the snout. These electroreceptor organs are called the ampullae of Lorenzini. Ampullae of Lorenzini are a network of jelly-filled pores, which allow the shark to detect electrical fields when prey are distressed or injured and aids in their capture. Also, when fish and other organisms give off an electrical field when swimming, the whitetips use the ampullae of Lorenzini to pinpoint their location.
Whitetip sharks release pheromones to mark their territory. The ampullae of Lorenzini help detect the pheromones. There isn’t any published information to state if oceanic whitetips use pheromones to find a potential mate. (Dingerkus, 1999; Tricas, 1999)
Oceanic whitetips are opportunistic feeders. They congregate around ships, looking for a meal. Whitetips often follow different species of whales such as pods of short-finned pilot whales (Globicephala). These whales use echolocation to target prey.
This species occasionally hunts in groups, helping one another to catch schools of fish. These sharks are fast-moving and competitive over food. Oceanic whitetips frequently participate in feeding frenzies. Feeding frenzies occur when multiple species of shark congregate and feed on one source of food. Whitetips and silky sharks (Carcharhinus falciformis) comprise these frenzies, but hypercompetitive whitetips outcompete silky sharks.
An oceanic whitetip's diet consists of cartilagenous fish such as stingrays, plus sea turtles, marlin, squid, tuna (Thunnus), mammal carrion, and sometimes garbage. (Helfman and Burgess, 2014; Myrberg Jr., 1999)
Humans (Homo sapiens) are the primary threat to the oceanic whitetip population. Humans use fishing techniques to capture the whitetips for the use of their dorsal fins.
Remoras (Family Echeneidae) are also called suckerfish and have been noted for attaching themselves to or riding along with sharks or larger marine animals. Remoras may act as cleaners by eating external parasites and also feeding on their hosts’ meals. Remoras have been observed attached to oceanic whitetips between the pelvic fins.
Oceanic whitetips are prodigious predators of other fish. Oceanic whitetips help maintain balance among the fish population. As a top predator, it is likely that oceanic whitetips impact the populations of the fish species that they consume. (Stafford-Deitsch, 1999)
Longline pelagic fisheries are catching and finning oceanic whitetips because of their particularly long dorsal fin. Finning is a method in which fishermen slice off shark fins and discard the body. This ultimately leads to the demise of the shark.
Oceanic whitetip sharks can be entangled as bycatch. Many of the shark’s body parts are profitable to humans. The large dorsal fin of the oceanic whitetip is used in traditional Asian dishes, particularly in shark fin soup. Shark fin soup is considered a luxury item is Chinese culture. Fish markets utilize shark meat frozen, smoked, and/or fresh. The shark’s skin is used for leather. Also, shark liver oil is a source of vitamins.
Shark cartilage is extracted for human research. This research searches for a potential treatment for the inflammatory called psoriasis. Psoriatic lesions develop in blood vessels and neovascularization (functional microvascular networks with red blood cell). Shark cartilage has an active agent (AE-941), which inhibits blood vessel formation. Antiangiogenesis agents such as the AE-941 in shark cartilage, provides key evidence that may help prevent such systemic diseases. (Dupont, et al., 1998; Schindler, et al., 2002)
Even though oceanic whitetip sharks reside and hunt primarily in deeper water, the shark is considered highly dangerous. Typically, oceanic whitetips are noticed initially after mid-ocean disasters like the U.S.S. Indianapolis. The sinking of the ship in 1945 and the crew jumping into the open ocean caused vibrations in the water that likely attracted oceanic whitetips. Of the 1,197 crewmembers that jumped ship, only 317 survived. It is believed that many of the fatalities resulted because of the oceanic whitetip. (Stanton, 2002)
Oceanic whitetip sharks are caught in substantial numbers, virtually everywhere in their range where, pelagic longline and drift net fisheries exist. Longline fisheries mainly catch tuna (Thunnus), but 28% of oceanic whitetips that are captured are finned as well. Oceanic whitetips have been problems to longline fisheries because of the sharks damaging the tuna. An estimated 2.1% of the oceanic whitetip populations are caught in shark bycatch in the swordfish fishery. Given these fisheries bycatches, oceanic whitetip sharks are listed by the IUCN as a “vulnerable” species.
The conservation of this species requires the cooperation of countries around the world. The United Nation's Convention on the Law of the Sea is an agreement, specifically for coastal states and fishing states. It established collaboration among these states and adoption measures to ensure the safety of the oceanic whitetip shark. Also, the FAO International Plan of Action for the Conservation and Management of Sharks (IPOA-Sharks) recommends Regional Fisheries Organizations (RFO) to assess the oceanic whitetip population find preventive measures regarding longline fisheries. Certain steps like banning finning in other countries, setting regulations on fishing, and having marine protected areas.
According to CITES Appendix II, there have been meeting votes to protect Oceanic whitetip sharks. Delegates in Thailand’s capital, Bangkok, have voted to protect the threatened oceanic whitetip species by regulating all trade through Hong Kong. ("Appendices I, II, and III", 2013; Baum, et al., 2015; Ebert, et al., 2013; McGrath, 2013)
Leanna Hall (author), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Emily Clark (editor), Radford University, Brenna Hyzy (editor), Radford University, Cari Mcgregor (editor), Radford University, Jacob Vaught (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in the southern part of the New World. In other words, Central and South America.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
an animal that mainly eats decomposed plants and/or animals
uses electric signals to communicate
A substance that provides both nutrients and energy to a living thing.
Animals with indeterminate growth continue to grow throughout their lives.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
makes seasonal movements between breeding and wintering grounds
eats mollusks, members of Phylum Mollusca
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
generally wanders from place to place, usually within a well-defined range.
found in the oriental region of the world. In other words, India and southeast Asia.
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
chemicals released into air or water that are detected by and responded to by other animals of the same species
an animal that mainly eats fish
mainly lives in oceans, seas, or other bodies of salt water.
an animal that mainly eats dead animals
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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