Oceanic Whitetip Sharks Carcharhinus longimanus love to cruise through tropical and temperate open oceans between 18-28ºC and are rarely found in shallow coastal waters.
They range in color from grayish-brown to bronze depending on their geographic location and have a distinctive white marking at the top of their large, rounded dorsal fin – hence the name whitetip.
The largest whitetips reach 4 m in length and can weigh up to 170 kg, females tend to be slightly larger than males.
They spend their time in the epipelagic layer of the ocean (upper layer), around 150 m (490 ft) below the surface.
Deceptively slow moving and solitary, this shark has been described to behave like ‘sea dogs,’ in that they approach animals cautiously, and will retreat to a safe distance. Then like dogs, they will wait for the perfect opportunity to return and sneak attack their prey. They also are known to follow ships the way a dog will follow their master.
These animals will also work together in complex “feeding frenzies”, and are the main culprits in many of the world’s shipwreck deaths.
For example, the USS Indianapolis which was a sizable war ship during WW2 with 1196 crew was torpedoed and sunk in 1945. Roughly 300 of the crew went down with the ship, leaving the rest in open water. Some died from exposure and other succumbed to their injuries, however many were attacked and eaten by sharks. Nobody can be sure how many people died as a result of the sharks but of the 900 that made it into the water only 317 survived. It is known as the worst shark attack in history.
Due to the sound of the explosions and sinking ships, plus the thrashing around and blood in the water, many oceanic whitetip sharks were attracted to the area.
Another infamous whitetip attack was when the British troopship the Nova Scotia went down 50 km off the South African coast in 1942. Of the 750 on board it is estimated that over a quarter were taken by oceanic whitetips.
According to scuba pioneer and renowned oceanographer Jacques Cousteau, these sharks are more dangerous than the Great White Shark because of their behavior.
Whitetips feed on bony fish and pelagic cephalopods. Although these are their main food sources they are not fussy eaters and have been known to eat turtles, birds and stingrays.
They are intelligent creatures and employ a variety of hunting techniques depending on their chosen prey. Whitetips have been seen simply swimming through schools of tuna with their mouths open, waiting for one of them to make a mistake (quite a costly mistake!) As well as this they can decimate a baitball in quick time by grouping together and biting into the school.
As well as a variety of live prey they also scavenge for whale carcasses.
These ocean predators are currently listed as ‘Vulnerable’ by the IUCN Red List and their population is decreasing. Between 1969 and 2003, there has been a 70% decline in their population numbers and that rate keeps growing every year. Between environmental pressures, the brutal practice of shark finning, and a slow reproductive rate, Oceanic Whitetip Sharks are in serious threat of becoming extinct.
Due to their large, distinctive dorsal fin they are prime targets for finning. This practice along with bycatch in longline and gillnet fishing gears has done serious damage to this shark species.
For example, in the 1950s it’s said that there would be between 2-25 whitetips constantly following fishing ships in the Gulf of Mexico – a hindrance because of the amount of tuna they damaged. Once known as the most common pelagic shark in the sea however now they are sadly a rare sight today in the Gulf of Mexico.
Article written by TerraMar’s Education Development Intern – Tom Carr