Researchers have discovered a 380-million-year-old heart preserved inside a fossilised prehistoric fish. They say the specimen captures a key moment in the evolution of the blood-pumping organ found in all back-boned animals, including humans. The heart belonged to a fish known as the Gogo, which is now extinct.

Lobster nets and pots have become such a threat to the survival of critically endangered North Atlantic right whales that the crustaceans have been “red-listed” as seafood to avoid by a major fish sustainability guide. Fewer than 340 of these whales exist today, including only 80 breeding females. The population is estimated to have dwindled by 28% over the past decade.

Scientists at the Florida Aquarium have made a breakthrough in the race to save Caribbean coral: For the first time, marine biologists have successfully reproduced elkhorn coral, a critical species, using aquarium technology. It’s a historic step forward, and one they hope could help revitalize Caribbean ecosystems and could pay humans back by offering extra protection from the fury of hurricanes.

Australia took a step Thursday toward combating climate change when the lower house of its Parliament passed a bill committing to reducing carbon emissions by 43% from 2005 levels by the year 2030, and reaching net-zero emissions by 2050.

Coral cover has bounced back across two thirds of the Great Barrier Reef

Military sonar can have a serious effect on some ocean animals. Could natural noises produced by sealife be used to locate undersea threats?

PAGE, Ariz. (AP) — Barrett Friesen steers a motorboat toward the shore of Lake Powell, with the Glen Canyon Dam towering overhead. Pale “bathtub rings” line the canyon’s rocky face, starkly illustrating how water levels have slumped in the second-largest U.S.

Climate change is threatening the world’s corals, but removing seaweed—like weeding a garden—can give some reefs a boost.

Bonefish off the coast of Florida have tested positive for a cocktail of pharmaceutical drugs, including anti-depressants and blood pressure medications, according to a new study.

Scientists in the Klamath Basin have begun prepping for the return of an untamed river...

Prof Terry Hughes says he believes bleaching is under way as the Australian government conducts monitoring flights over 2,300km reef

About 51 trillion microplastics are floating in the surface waters of oceans around the world. Originating from various types of plastics, these tiny fragments (less than 5 millimeters in length) pollute natural ecosystems. Hundreds of studies have surveyed plastic debris on the surface or near surface of the ocean. However, these studies only "scratch the surface," and do not provide a complete inventory of what's lurking beneath.

River Dee initiative comes as rising water temperature from climate heating threatens species’ survival

Meet Methuselah, the fish that likes to eat fresh figs, get belly rubs and is believed to be the oldest living aquarium fish in the world. In the Bible, Methuselah was Noah’s grandfather and was said to have lived to be 969 years old. Methuselah the fish is not quite that ancient, but biologists at the California Academy of Sciences believe it is about 90 years old, with no known living peers.

A beloved fish with a rich history has become hard to find—will it rise again?

Scientists made an incredible discovery in November: acres of giant, pristine, rose-shaped corals blossoming from the sea floor in what's known as the ocean's "twilight zone."

A budding industry that aims to catch zooplankton for health supplements and fish food has scientists fearing that its effects on marine ecosystems could be devastating

‘Seeing one in real life is indescribable,’ says marine biologist of the technicolour marine mollusc she spotted off Queensland

It is the first time an extinct species of fish has been successfully reintroduced in Mexico

Researchers from the University of Adelaide have found that the way fish interact in groups is being upset by ocean acidification and global warming.