Celebrating the worlds largest fish on International Whale Shark Day

Whale shark on the Ningaloo Reef, Australia. Source: Daniel Browne, on tour with Coral Bay Ecotours

International Whale Shark Day is held every year on 30th August, in celebration of the World’s largest fish. This annual day of celebration was established in 2012 to raise awareness around the importance of whale sharks in our oceans and encourage efforts for their conservation.

On the Ningaloo Reef, these amazing creatures are celebrated many days of the year by thousands of people who visit the region to tick this interaction off their bucket list. Between the months of March and July (sometimes longer), it is estimated that 350-500 individual whale sharks make their way to the Ningaloo region, primarily to exploit the abundance of food in the area. Their arrival begins around the time of the major annual coral spawning event in March, which provides a major food source for these filter-feeding fish, who feed exclusively on microscopic animals such as krill, small fish, larvae, fish eggs and coral spawn.

Whale Shark vs Whale. Adapted from https://oneworldoneocean.com/

Whale Shark approaching back of vessel, Thunder. Source: Alex Kydd, on tour with Coral Bay Ecotours

The Ningaloo Reef tourism industry is the leader in sustainable whale shark tourism, and this aggregation of Whale Sharks is the most researched population in the world. In recognition of these wonderful marine animals, we have put together a collection of interesting facts about Whale Sharks for our readers:

• As the largest fish in the ocean, whale sharks reach a maximum size of around 15 metres. The largest individual ever recorded was 20m, but nowadays the average size of whale shark encountered is between 5.5-10m.

• Whale sharks are slow growing animals thought to live to 130 years of age

• Tagged whale sharks have been recorded diving to depths of over 1900m

• Whale Sharks get their name from their size and feeding mechanism, which is similar to that of baleen whales. They are not whales, they are most definitely fish!

• The skin of a whale shark can be up to 30cm thick. This tough skin provides protection from predators, and great insulation.

• Whale sharks are found in all tropical oceans of the world, but there are only a few locations where reliable aggregations have been recorded. These locations include the Maldives, Galapagos, Philippines, Seychelles, Mozambique, Belize, Southeast Asia, Mexico and here on the Ningaloo Reef.

• Most of the known aggregations of whale sharks around the world consist almost exclusively of juvenile/sub-adult male individuals in coastal regions. It appears that male and females, juveniles and adults all use different habitats. Where are the adults? Where are the females? Where are the babies? Where do they mate and give birth? So much is still unknown about these creatures.

Area of the whale shark used to identify individuals. Source: Sharkbook.ai

• Like a human fingerprint, every whale shark has a unique spot pattern that can be used to identify individuals. Taking ID photos is a non-invasive way to ID individuals and contributes to population data on whale sharks. The technology used to map the spot patterns from the photographs was adapted from a NASA star mapping program. This information can be used to assist with conservation and management plans for whale sharks

• Whale sharks are listed as ‘Endangered’ on the IUCN List of Threatened Species, meaning that their populations are in decline world-wide. Research suggests that population numbers have decreased by over 50% in the past 75 years.

• The only known natural predator to adult whale sharks is orcas. Juvenile whale sharks are more vulnerable to predation and have been found in the stomachs of large pelagic fish such as marlin.

• Having no real natural predators in the wild, whale sharks are under threat solely due to human activities. Demand for whale shark meat, fins and oil remains a big threat to whale sharks in some parts of the world due to unregulated fisheries. Entanglement in fishing gear, vessel collision, habitat destruction and unregulated tourism are other threats which contribute to their decline.

• There are some amazing research organisations and charities working around the world to learn more about whale sharks in an effort to contribute to management plans and policies for the conservation of the worlds largest fish. To find out more, you can visit the following sites: http://whaleshark.org.au/ https://marinemegafauna.org/ https://maldiveswhalesharkresearch.org/ https://galapagosconservation.org.uk/projects/whale-shark-monitoring/

Swimming with the world’s largest fish with Coral Bay Ecotours. Source: Daniel Browne

If you’d like even more exciting facts about whale sharks, Dr Simon Pierce (whale shark researcher extraordinaire) put together a great piece and it can be found at https://www.naturetripper.com/articles/whale-shark-facts

Only 1 in 3 million people will swim with Whale Sharks in their lifetime. Join our Whale Shark Safari and witness these amazing creatures for yourself!