Expedition to Papahānaumokuākea yields more Incredible Discoveries

Rare species at a depth of 300 feet at Kure Atoll in Papahānaumokuākea Marine National Monument. Left: a new species of wrasse (family Suezichthys). Center: unidentified species of sea urchin. Right: Struhsaker’s damselfish (Chromis struhsakeri), never before seen by divers (this species of fish was previously known only from deep trawls and submersible observations). Credit: NOAA and Richard Pyle/Bishop Museum

Scientists that returned from a 28-day research expedition in September to explore the deep reefs within PMNM recorded numerous species of marine life never before seen, including a possible new species of seahorse, and a sea star not previously found in Hawaiʻi.

A new species of seahorse collected by NOAA scientists at 300 feet on Pioneer Bank inside Papahānaumokuākea Marine National Monument. Credit: Brian Hauk/NOAA

A sea star not previously recorded from Hawaiʻi. Credit: NOAA and Robert Whitton/Bishop Museum

Using advanced diving technology to survey reefs at depths up to 300 feet, much deeper than conventional SCUBA gear allows, scientists explored never-before-seen ecosystems. Fish surveys at these depths around the northernmost atolls revealed an extremely high abundance of species found only in the Hawaiian Islands. On some of the deep reefs surveyed, 100% of the fishes recorded were endemic – meaning that they are all unique to the Hawaiian Islands.

This is the highest level of endemism recorded from any ecosystem on Earth.

A high-endemism reef fish community at 300 feet on Kure Atoll inside Papahānaumokuākea Marine National Monument. Every fish in the picture is a Hawaiian endemic species (not known from anywhere else except Hawaiʻi). Credit: NOAA and Richard Pyle/Bishop Museum

The team was the first to dive on several open-ocean seamounts in the Monument, which were first mapped using high-resolution multibeam sonar in 2014 and 2015. These undersea mountains rise from the seafloor at depths over 16,000 feet and some summit within 200 feet of the surface.

NOAA scientist Brian Hauk and Bishop Museum scientist Richard Pyle descend to a reef at 300 feet on Pioneer Bank, Papahānaumokuākea Marine National Monument. Credit: NOAA and Robert Whitton/Bishop Museum

Scientists collected specimens and photographs of new records of marine life from the seamounts, including potential new species of fish, algae and invertebrates. The specimens will be sent to experts at various museums around the world to confirm the identity of the organisms.

In addition to studying the Monument’s environment, the deep divers were in turn the subjects of a medical study to understand the effects of extreme dive exposures on human physiology. Neal Pollock, Ph.D., research director of Divers Alert Network (DAN), led a team that conducted ultrasound imaging of the divers’ hearts after ascent from deep dives.

Divers Alert Network researcher monitoring diver’s heart after a deep dive. Credit: Jason Leonard/NOAA

Formation of gas bubbles in the bloodstream on ascent from deep dives is known to cause decompression sickness, or “the bends,” a potentially life-threatening condition. It is hoped that information collected during the expedition will make SCUBA diving safer for scientific divers as well as recreational divers.

The scientific team included researchers from NOAA's Office of National Marine Sanctuaries, NOAA's Pacific Islands Fisheries Science Center, the Hawaiʻi Institute of Marine Biology, the Bernice P. Bishop Museum, and Divers Alert Network.

Read the Press Release.

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