The species listing below comprises an additional 29 species of marine benthic algae within the Papahānaumokuākea Marine National Monument (PMNM), a world Heritage site, which encompasses an area of 360,000 km2 of the Northwestern Hawaiian Islands. The 10 islands, atolls and shoals within the PMNM, aligned from northwest to southeast, include Kure Atoll, Midway Atoll, Pearl & Hermes Atoll, Lisianski Island, Laysan Island, Maro Reef, gardner Pinnacles, French Frigate Shoals, Necker Island and Nihoa Island. The 29 new records for the PMNM consist of 1 species of Cyanobacteria, 23 species of Rhodophyta, 1 species of Phaeophyceae and 4 species of Chlorophyta, which were primarily reported by Abbott (1999) and Abbott & Huisman (2004) from at least one of the Main Hawaiian Islands (MHI) to the southeast. other references which report species from the MHI are cited with the islands where the species were previously reported. These 29 species increase the number of marine benthic algal species found in the PMNM from 335 (Tsuda 2014) to 364 species or by 8.6%. Voucher specimens with BISH numbers are deposited in Herbarium Pacificum (BISH) of the Bishop Museum. Voucher specimens with NwHI numbers are presently deposited in the Alison R. Sherwood Laboratory at the University of Hawai‘i-Mānoa. AlgaeBase (guiry & guiry 2015) was consulted for current names and synonyms. Two specimens were initially identified morphologically as the invasive species Gracilaria salicornia (C. Agardh) e.y. dawson and Hypnea musciformis (wulfen) J.V. Lamouroux present in the MHI; however, molecular analyses (using the UPA region) ruled out the initial identification and document the specimens here as Gracilaria sp. and Hypnea sp.

Depth range
23- 70 m

Mesophotic “mentions”
1 x (total of 2139 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'mesophotic coral ecosystem'

Fields
Taxonomy

Focusgroups
Algae (Macro, Turf and Crustose Coralline)

Locations
USA - Hawaii

Platforms
SCUBA (open-circuit or unspecified)