<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/ReefBeforeAfter.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/ReefBeforeAfter.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/ReefBeforeAfter.jpg?v=ap&w=980&h=551 800w" > 1 of 8 The photo on the left shows a school of fish on Rapture Reef in the French Frigate Shoals before Hurricane Walaka passed over the area last year. The photo on the right shows the same reef now. (NOAA)

At a Glance Researchers surveyed the reefs this month for the first time since Hurricane Walaka pummeled the region last year.

The same hurricane also wiped a small island off the map.

Both the island and reef are located in one of the largest marine conservation areas in the world. When University of Hawaii researcher Kailey Pascoe dove down to a coral reef in the remote northwestern Hawaiian Islands recently, she expected to see the vivid colors and schools of tropical fish she remembered from her first visit four years ago.

Instead, Pascoe told the Honolulu Star-Advertiser, she saw a wasteland .

"It was kind of devastating," Pascoe said.

The coral. The fish. All of it had disappeared, wiped away by Hurricane Walaka in October.

"When we got down there, it was quite shocking because it was essentially flat, no coral, and rubble," she said.

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Pascoe just returned to Honolulu from a 22-day voyage with a team of other researchers aboard the NOAA ship Rainier. Their mission was to check on reefs in Papahanaumokuakea Marine National Monument, pummeled by Hurricane Walaka, which was Category 3 strength at the time. It was the first time anyone had surveyed the reefs since.

"After the hurricane, those reefs are gone," Randy Kosaki, Papahanaumokuakea’s deputy superintendent of research and field operations, who was also on the voyage, told the Star-Advertiser. "Not even damaged. They’re just gone."

The hurricane also famously wiped out East Island in the French Frigate Shoals, the same region of the vast marine national monument where the dead coral lies. The monument encompasses more than 582,578 miles of the Pacific Ocean and is one of the largest marine conservation areas in the world. It's not easily accessible to the public and is mostly visited by scientists and researchers.

The dead coral wasn't the only discovery that stunned the researchers. They also found an invasive type of algae covering huge swaths of shallow coral reefs. They aren't sure exactly what it is, so they gathered samples to try and solve the mystery and figure out how to stop it from spreading. The mystery was so puzzling that the researchers canceled all other planned activities for the voyage to focus on it.

"When you have an invasive species like this come in and basically destroy the existing reef and wipe out the corals and native limu, there’s nothing really there to document," Heather Spalding, an algae expert who was on the expedition, told the Star-Advertiser. "So it’s really disheartening, and important that we limit the spread of this invasive alga, and really try and find out where it occurs now so we don’t spread it further."