Whale shark filter-feeding in slow motion: A plankton's worst nightmare! Earlier this month, the International Union for Conservation of Nature (IUCN) released its latest red list assessment which has upgraded the whale shark from vulnerable to endangered. The organization cited fishing and ship strikes as key reasons the population has more than halved in the past 75 years. Whale sharks are one of only three filter-feeding sharks in the world, and are highly migratory animals, widely distribute