Scientists over the past month have explored coral reefs in the remote Northwestern Hawaiian Islands that until recently were considered too deep for scuba divers to reach.
Divers swam among previously unseen reefs as deep as 76 metres during a month long research trip to the islands by the National Oceanic and Atmospheric Administration vessel Hiialakai.
They found nursery grounds for juvenile reef fish like parrotfish and butterflyfish and were able to collect specimens that may help them identify new species.
The research mission's lead scientist, Randall Kosaki, says they saw reefs that no human had ever laid eyes on before.
The largely uninhabited Northwestern Hawaiian Islands were made a marine national monument in 2006.