NOAA Divers Conduct Research from NOAA Ship Hi'ialakai
NOAA Diver Jason Leonard lays down a transect line while conducting research at 300 ft. in the Northwestern Hawaiian Islands. In June 2016, NOAA Divers in this mission reached a maximum depth of 330 ft.
NOAA and University of Hawaii scientists recently concluded a 25 day research trip onboard NOAA Ship Hi’ialakai to the Northwestern Hawaiian Islands (NWHI) and the Papahānaumokuākea Marine National Monument (PMNM).
NOAA Divers characterized deep coral reefs by conducting fish and benthic surveys in the mesophotic zone (diving to a maximum depth of 330 feet in depth) using closed circuit rebreathers. New species were found not previously known to science or to the NWHI. The mesophotic zone, also called the twilight zone to describe the diminished availability of light at this depth, is generally considered to be between 150 to 500 feet deep. While divers usually study areas down to 100 to 150 feet and remotely operated vehicles explore zones in excess of 500 feet in depth, the mesophotic zone has been largely unexplored. To prepare for these deep dives (the deepest NOAA dives on record as of June 2016) the PMNM divers performed progressive training and proficiency dives as a team and carefully planned research activities closely with the NOAA Diving Control and Safety Board (NDCSB).
Other projects were also conducted using open circuit scuba diving to depths from 10-80 feet. Coral disease surveys were performed with an emphasis on reefs off Lisianski Atoll to compare current reef conditions with those of years past to determine the effects of a mass bleaching that occurred two years ago.
Additionally, several monitoring receivers used to track apex predator movements (predators at the top of a food chain) along the NWHI archipelago were retrieved and replaced. The data from the collected receivers will be added to existing data while the recently deployed receivers will be collected next year.
Lastly, surveys were conducted to assess the density of moray eels within the NWHI as part of a comparison study with moray eel densities found in the main-eight Hawaiian Islands.
During the trip, a total of 110 closed circuit and 299 open circuit dives were conducted.