Whale sharks on the move

whale-sharks-on-the-move

The whale shark business is booming on the Azores since whale sharks seem to have found a new home around the volcanic islands near Portugal.

These waters are significantly colder than the tropical ones whale sharks usually prefer. Originally whale sharks like temperatures ranging from 26,5 to 30 degrees Celcius, that’s why they are found along the coasts of South-Africa, Australia, the Philippines and Mexico where the ocean is nice and warm. But climate changes alters their behavior and makes them search for different places to live. The University of the Azores studied this behavior and their research was recently published in the journal PLoS ONE.

Whale sharks have been spotted occasionally in the Azores, but the hot summer of 2008 led to a big increase of sharks and since then they never left the area. Tuna fishers in the region searched the ocean for the pintados (spotted ones), since whale sharks are likely to carry a school of tuna underneath them. Given its gigantic size they were obviously much easier to find than tuna. The data gathered by these fishermen over the years was used by the researchers to investigate behavioral patterns.

The area where whale sharks have been seen covers over 1 million square kilometers. Research revealed that the wales are not only more likely to be found in waters with higher temperatures but also in areas with underwater hills and mountains, because it’s a great food source for plankton. Another factor why whale sharks might stay in the area is to mate.

These findings are important to predict the consequences of global climate change on the behavior of whale sharks and other marine animals. It might give us an insight in how the sharks will distribute themselves in the future.

Sources:

Jennifer Vegas, “Climate-Challenged Whale Sharks Flocking to Island Chain”, Discovery News, 2014-07-16
“Whale Shark Alert: World’s Biggest Fish Seek New Home”, NBC News, 2014-07-18