WOD2014 – Whale Sharks

This Sunday is World Oceans Day; a day that commemorates the beauty and importance of our oceans which are so integral to our survival. As can be expected for a tropical archipelago, the Galapagos Islands have an especially intimate relationship with the seas. In the run-up to World Oceans Day we shall be posting a series of daily blog articles on the marine wildlife and associated conservation projects in Galapagos. Today’s post focuses on the magnificent whale shark.

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Imagine swimming in the open ocean, surrounded by nothing but a vast expanse of blue. Around you, the churning currents and tides fill your ears with the sound of the gurgling sea. Small groups of silvery fish dart in and out of your sight. Suddenly, a gigantic shadow appears and starts to get closer.

As the shadow-maker approaches and its form becomes clearer, you can’t help but feel a sense of primal fear. The massive animal is the size of a bus, with a gaping mouth that spans over a metre. But there is no need to worry; this gentle giant pays you little heed and swims past, the mottled white flecks on its skin blinking in the sunlight that penetrates down from the surface. You have just met a whale shark.

The whale shark is the largest fish in the world, growing up to 18 metres long. It is found in all tropical and warm waters except for the Mediterranean. Fortunately for most creatures (us included), the whale shark is a filter feeder, primarily eating microscopic plankton and small fish.

At certain times of year whale sharks tend to aggregate in specific locations, or ‘whale shark hotspots’ as they are known. These seasonal abundances generally coincide with periods of high local food productivity and last for several months.

In the Galapagos Islands, whale sharks are most common between the months of June and December. These gigantic fish stay in the Galapagos Marine Reserve for a few days before swimming beyond the boundaries of the park on what appears to be a long migration path.

Last year, GCT ran the Whale Shark Appeal to raise funding for the Galapagos Whale Shark Project, a conservation initiative that aims to increase our understanding of these mysterious animals. The project has already produced some very interesting findings: fascinatingly, it appears that up to 98% of the whale sharks that pass through the Archipelago are heavily pregnant females, something which has been seen nowhere else on Earth. Given that nobody knows where whale sharks breed, give birth or spend the first few years of their life, this is a very interesting and important finding.

Like many animals worldwide, whale shark numbers are decreasing and the species is listed as vulnerable on the IUCN Red List. Improving our understanding of whale sharks will ultimately help authorities to provide better protection for them, something which is of pressing importance.

Despite our limited knowledge and the whale sharks internationally protected status, the species is still being targeted by some fisheries. Earlier this year it was uncovered that a whale shark factory was operating in Wenzhou, China, reportedly slaughtering 600 of the sharks annually.

As we approach World Oceans Day, be sure to remember that the lives of various animals, including whale sharks, are becoming increasingly uncertain. This weekend, why not take a trip down to the nearest beach and look out to the horizon? Remember that the oceans link all of us together and we cannot afford to destroy the balance between Earth’s ecosystems.

And then, on your way back, why don’t you pick up that piece of litter and put it in the bin? Every little bit helps.

by Jose Hong