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Using satellite tags and deep-water remote operated vehicles, a team of researchers were able to take a closer look at what has been dubbed as a “White Shark Cafe” in open water between California and Hawaii.

The month-long expedition, which was a joint effort by scientists from Stanford University’s Hopkins Marine Station, the Monterey Bay Aquarium Research Institute, and the Schmidt Ocean Institute, used a multitude of research methods to better understand a mysterious gathering point in the middle of otherwise barren ocean. The researchers became aware of the remote gathering point thanks to 20 tagged sharks that congregated in the area in May.

Data taken by the satellite tags revealed that the sharks would dive to great depths in this area. ROVs would then be deployed to the area to get a shark’s eye view of the underwater environment.

“For me, there is no substitute for direct observation. I want to see what’s there. If I can’t go down myself, then the next best thing is to use a remotely operated vehicle,” MBARI biologist Bruce Robison said.

The interdisciplinary research effort used echo sounders, sampling nets and environmental DNA samples to get a complete picture of what drew the large sharks here on their migration. Rather than a barren desert, Robison and his colleagues discovered what he called “an ocean oasis.”

The researchers found deep layers of phytoplankton that were not visible in satellite images. These algae, along with the larger animals observed, suggest that the area is more biologically productive than the researchers expected.

“We found a high diversity of deep sea fish and squids (over 100 species), which in combination with observations made by the ROV and DNA sequencing, demonstrate a viable trophic pathway to support large pelagic organisms such as sharks and tunas,” lead researcher Barbara Block said.