Researchers exploring the deep waters of Fiordland have discovered an enormous black coral measuring 4 meters (13 feet) tall and 4.5 meters (15 feet) wide.

The protected coral is estimated to be 300-400 years old and is believed to be among the largest black corals ever recorded in the waters of Aotearoa New Zealand.

Professor James Bell, a marine biologist at Te Herenga Waka -- Victoria University of Wellington, described the find as "absolutely huge."

"It's by far the largest black coral I've seen in my 25 years as a marine biologist. Most black corals we come across when we're diving are small, with the bigger ones usually less than two to three meters tall so finding this one was really cool," he said.

Why Large Black Corals Matter