Whale shark is the gentle giant of the shark family

Biggest fish in the seven seas

Swimming next to a whale shark in warm tropical water and whatch him feeding is a very special experience, one will never forget! This can happen in different places all over the world like Mexico, Thailand, Phillipines and many more, as long as the water is warm enough. They like it tropical, at least 21 Celcius (69.8F). Very famous for its whale sharks is the Mexican Caribbean.

From Cancun, Isla Mujeres and Isla Holbox you can go by boat to the whale shark spots off shore. And most likely you will also see giant manta rays and dolphins! This is only possibe during certain months, from June to September. But why they are coming exactly during that time in groups of hundreds?

Big mouth, small food

Whale sharks are eating mostly plankton like krill, fish eggs and larvae, also small fish or squid. They are so called filter feeder because they filter their food out of the water. To do so they swim and press the water along the filter pads through their gills or suck in volumes water by opening and closing their wide mouth. When the water is full of plankton they sometimes stand vertical for minutes to filter, their mouth right at the surface!

Their mouth fits for the biggest fish in the world, it can be upt to 1.5m (4-5ft) wide! But their throat is very small, so it´s impossible that they accidentially "swallow" a swimmer, they are truly gentle giants.

How much does a whale shark eat?

A whale shark of around 6 m (18ft) total length can filter around 600 cubicmeter water per hour, which are 6000 liter! From this amount of water they receive estimated 2,7 kg of plankton biomass. During a day that provides them with 6700 kilo calorie of energy. Yes, that´s a lot, but they need it: A female animal was satellite tagged and swam in 150 days at least 7,213 km from the Caribbean to the South Atlantic ocean!

How big is the biggest fish?

Based on stories of fishermen around the habitats of whale sharks, some have reached a lenght of 21m (69ft)! Scientific more reliable sightings measured a lenght of up to 18,8m (62ft), which is a bit less but still impressive. But these are rare encounters, in average they are 9.8 m (32 ft) and weighting 9 t (20,000 lb). Between 6 and 10m are the ones that snorkellers can see during the excursions in Cancun with Frogman Diving Cancun.

Whale or shark?

Whale sharks are sharks and so the biggest fish. Whales are mammals, hence no fish and some species grow way bigger. But they are feeding plankton like most of the big whale species, for example the blue whale or humpback whales.

There are only two other shark species that also feed plankton, the megamouth and the basking shark, though none grows as big as the biggest fish.

Shark babies

Little is known about where and when whale sharks are mating or where they give birth. Females breed the eggs inside their body and gives birth to living pups, 40 to 60 cm (16 to 24 in) long. Up to 300 eggs a single female can carry, she keeps sperm from one mating and produces continously pups over a certain period.

It takes 30 years for the biggest fish to reach sexual maturity, which makes them vulnerable. Especially younger ones often die from accidents with boats before they are old enough to reproduce. If they don´t have fatal encounters with boats, ghost nets or illegal Chinese shark finning poachers, they can become 100 years old!

Fish friends

Whale sharks share their feeding preferences with manta rays. Together they filter the same feeding grounds for their favoured plankton soup. In Cancun it is very common to see the elegant giant manta rays flying by in formations.

Whale shark conservation

Unfortunately these beautiful creatures are listed as endangered by the IUCN. As mentioned before their late sexual maturation and the human impact is stressing the global population. It is not much known about the biggst fish and there is no proper estimation of the size of the global population. One important project for conservation and research is whaleshark.org, the wildbook for whale sharks. Here everybody can upload pictures he made during encounters around the world.

Every individual has a unique pattern of stripes and dots and with a proper photo taken from the side a software can identify him. If he was spotted before, you will receive a list of the encounters. If not, you can even name it!