Pacific angelshark. Santa Catalina Island, California
There are over 465 known species of sharks, ranging from the planet's largest fish—the whale shark—to the palm-size dwarf lanternshark. These misunderstood predators not only fascinate us, but surprise us with their beauty and vulnerability. Due to overfishing and discriminatory killing, among other causes, at least a quarter of sharks and rays may be headed for extinction, according to a 2014 report by the International Union for Conservation of Nature.
"For the artist within me, sharks represent an endless well of inspiration, a blend of grace and power that lures me into the sea," National Geographic photographer Brian Skerry wrote of his more than 10,000 hours spend photographing sharks.
"As a journalist, I'm driven by a sense of responsibility and a sense of the urgent need to broadcast that sharks are in trouble and need our help."
Here is a closer look at these charismatic creatures.