Scientists with New Zealand’s National Institute of Water and Atmospheric Research traversed 3,800 square miles of “never before seen” mountains and canyons — all under 700 to 1,500 feet of water.

The research evaluated the stretch of underwater terrain in four deep-sea regions of the Kermadec Ridge in the South Pacific. The point was to take stock of the sea creatures below to understand how human activity could affect what was down there, according to National Geographic.

“In order to ensure that deep-sea ecosystems do not suffer too much damage from things like bottom trawling or mineral extraction, we need to know what animals occur there, and how vulnerable they are to impact,” Malcomb Clark wrote to National Geographic.

Here are some photos of what they discovered below the depths:

New Zealand Scientists Study Kermadec Ridge and Return With Photos and Video of Deep Sea Organisms

Sea slug (Photo: NIWA via National Geographic)

New Zealand Scientists Study Kermadec Ridge and Return With Photos and Video of Deep Sea Organisms

Tonguefish -- notice it has both eyes on one side. (Photo: NIWA via National Geographic)

New Zealand Scientists Study Kermadec Ridge and Return With Photos and Video of Deep Sea Organisms

Squat lobster. (Photo: NIWA via National Geographic)

New Zealand Scientists Study Kermadec Ridge and Return With Photos and Video of Deep Sea Organisms

This squid is commonly called the Mickey Mouse squid. (Photo: NIWA via National Geographic)

New Zealand Scientists Study Kermadec Ridge and Return With Photos and Video of Deep Sea Organisms

Crown jellyfish (Photo: NIWA via National Geographic)

With 50 different underwater volcanos along the ridge, according to the press release, there are a diverse number of habitats for life on hydrothermal vents or on peaks and valleys.

“The benthic community on Tangaroa seamount, a combination of mussels and barnacles and shrimps, isn’t unique, but differs from that found on a number of neighbouring seamounts. The seamount communities were also very different from those we observed and sampled on the slope and canyons, which typically had muddy seafloor, rather than rocks.

“This trip confirmed our working hypothesis that the environments generated in these different deep-sea habitats vary in their characteristics, and they result in faunal communities that can differ, within close proximity,” Clark said in a statement. “The implication is that the exploitation of one seamount could have an effect that is not the same as the seamount close by,” says Dr Clark.

This video shows a slideshow of images of species collected:

With thousands of samples collected, Clark said there is the expectation they will identify some new species as they continue to research the specimens.

See more photos of the creatures found on the expedition here.