August 17, 2018 — Where do the biggest fish in the sea go to find enough food? Turns out, not too far, if they live in a region with lots of food.
Whale sharks (Rhincodon typus) swim about 25 kilometers (15 miles) per day and can make some tremendous long-distance oceanic movements. Scientists recently tracked a female whale shark from the eastern Pacific to the western Indo-Pacific for 20,142 kilometers (more than 12,000 miles) over 841 days, the longest whale shark migration route ever recorded.
Juvenile sharks in a series of four studies, one in the Philippines and three in the western Indian Ocean, apparently prefer to swim laps around their favorite feeding grounds.
Whale sharks are the world’s largest fish, growing up to 12 meters (40 feet) long and weighing up to 25 tons; even juveniles are 7 to 9 meters (23 to 30 feet) long. Scientists are keen to understand where these huge fish spend their time to better conserve them.
Fishing activity threatens whale sharks through direct killing, capture as bycatch, and boat strikes. Half of the world’s whale shark population has been killed since the 1980s, primarily by fisheries in China, India, the Philippines and Taiwan, and Chinese fisheries still target whale sharks for their fins and meat. The rapid decline in whale sharks’ global population prompted the International Union for the Conservation of Nature (IUCN) to reclassify the species as endangered in 2016.