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Oceanic Whietip Sharks

I had the most absolutely incredible experience during Mermaid Week Tahiti 2019 with Mermaid Kat when I swam with a pod of pilot whales while an oceanic white tip shark followed us. It was magical! I felt like I was part of the pod, right where I belonged.

The oceanic white tip shark, Carcharhinus longimanus, is the 4th most dangerous shark in the world and it was an honor to get to swim with some in Tahiti. According to a January 2021 study, their species have declined by 71% in 50 years. They are commercially used for their fins, meat, and oil and are eaten fresh, smoked, dried, or salted while their hides are used for leather.

They are a medium-sized requiem shark, growing to 4 meters (13ft), with the largest weighing in around 170kg (370 lbs). The females grow larger than the males by about 10cm (4in). In the 1950s, their mean weight was 86.4kg (190lbs) and by the 1990s the average weight was down to 56.1kg (124lbs). They are grey-bronze colored dorsally and white ventrally; most of their fins have white tips and can be mottled. Juveniles can also have black markings. They have saddle-like markings between their two dorsals and have larger fins than most other sharks. Longimanus is Latin for long hands, which correlates to the size of their pectoral fins. Both their pectoral fins and their dorsal fins are long and wing-like. They have a round nose, circular eyes, and round fins.

Oceanic whitetips are found globally in deep, open oceans in waters warmer than 18 C (64 F) and shallower than 150m (490 ft). Around ocean islands such as Tahiti and Hawaii, they can be found closer to land at depths of 37m (120 ft). They’re active during both the day and the night and are slow moving sharks.

While they tend to be loners when it comes to their own species, oceanic whitetips have been known to hang out with pilot whales, dolphinfish, and remora. They’ll follow baitfish migrations that accompany ocean-bound ships as well and are the most common shark to follow ships.

This helped lead to the “sea dog” name sharks were given in the 16th century as oceanic whitetips display dog like behavior when it comes to food - their movements get more avid and they approach the food cautiously but stubbornly, retreating and maintaining distance until it is safe to rush the food. Jacques Cousteau crowned them the “most dangerous of all sharks” due to the fatal bites they give human victims of shipwrecks and plane crashes.

They mainly feed on squid, octopus, cuttlefish, and other pelagic cephalopods as well as bony fish, but will vary their diet and be less selective. They can be aggressive when feeding with other species.

Oceanic whitetips are viviparous, meaning the embryos develop in utero and are fed by the placental sac. The gestation period is one year and litter sizes can vary from 1 to 15 pups. When they’re born, oceanic whitetips are only 0.6m (24 inches). Males mature between 1.7-1.9m (5.6-6.2ft) and females mature between 1.8-2m (5.9-6.6 ft).

The International Union for Conservation of Nature Red List lists Oceanic Whitetips as critically endangered. In the Gulf of Mexico, populations declined by 99.3% from 1950-1990! In 1995 they were added to the UN Agreement on Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks, which required fishermen to adopt measures to conserve the species but this has produced little visible progress.

They are fully protected in New Zealand waters under Wildlife Act 1953 which was signed in 2013. Also in 2013, they were added to Appendix II of CITES, which applied fishing and commercial regulations. In 2018, NOAA added them as a threatened species under the United States Endangered Species Act.

When swimming with oceanic whitetips like we did, there are a few safety factors to keep into consideration. While there have only been 5 fatal bites not related to shipwrecks or plane crashes since 2009, oceanic whitetips are wild animals and can become overwhelmed which can lead to a need to defend themselves. In Tahiti, we assisted on helping a shark bite victim that was injured by an oceanic whitetip following a pod of pilot whales.

As I just mentioned, oceanic whitetips can become overwhelmed. Because of this, there should only be 1, or at most 2, groups of people around the same shark or pilot whale pod (an oceanic whitetip shark is found following a pod of pilot whales about 80% of the time, so it should always be assumed that there is a shark with the pod). Additionally, the guide or professional should always stay in between the group of tourists and the shark. Always maintain eye contact with the shark and remain calm. Flailing about can give the illusion that the swimmer is already injured and dying, driving the shark to investigate.

Oceanic whitetips are a beautiful species and following the proper safety protocols can lead to an amazing interaction with these creatures. As always, make sure you are using a reputable company and never dive alone!

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