Underwater photographer Brian Skerry captured this image of his assistant and a curious southern right whale from Auckland Islands, New Zealand, after swimming with a pod of whales for nearly two hours.
Scattered marine debris along the floor of Suruga Bay in Japan poses a range of threats to this yellow goby and other marine life -- toxic substances often leach into the surrounding water, and large pieces of debris can create choking hazards.
A tiny translucent shrimp -- half the size of a grain of rice -- rests on a colorful sea anemone.
As polar ice sheets break away and return less and less each year, harp seals such as this one from the Gulf of St. Lawrence, Canada, face increasing challenges to maintain stable populations.
A spinyhead blenny peeks out of living coral to search for food off of the coast of Belize.
As the Earth's global climate continues to warm and polar ice disappears, beluga whales such as this one from Nova Scotia, Canada, struggle to adapt to their new environment.
This Bahamian oceanic whitetip shark, known for the distinctive coloring on its white-tipped, rounded extremities, is part of a globally threatened species due to overfishing demands, primarily for its fins.
Despite ongoing conservation efforts, Manatees, such as this one from Crystal River Water, Fla., continue to be endangered due to polluted waterways and boat strikes.
Sea angels, such as this one from Hokkaido, Japan, are tiny shell-less creatures at the base of the ocean's food chain whose survival is threatened by the Earth
Leatherback sea turtles, such as this one from Trinidad, face several ecological pressures caused by human activity, including drowning in fishing nets as bycatch, losing their offspring as a result of overharvested eggs, and competing with coastal development to access critical nesting beaches.