A baseline survey of the marine biota of the island of Lanai was conducted in May 2005. This was first comprehensive study that has been made on this island for all components of its marine nearshore community. Samples and observations were taken at seven sites around the island, and all macroalgae, macroinvertebrates and fish species collected or observed were recorded. On-site observations without collections were made at two other sites. Identified species were designated as native, nonindigenous (introduced) or cryptogenic (neither demonstrably native nor introduced) according to criteria used for previous introduced species surveys in Hawaii. A total of 294 taxa were observed or identified from collected specimens, which included 16 introduced or cryptogenic species and three new reports for the Hawaiian Islands. The 16 introduced and cryptogenic species comprised 5.4% of the total identified taxa and included seven cnidarians, one polychaete, two pericards, one decapod, one bryozoan, two ascidians and three fish. By station, the introduced/cryptogenic component ranged 3 to 7 species and 3.8% to 6.8% of the total biota. The stations included two sites at or near Kaumalapau Harbor, Lanai's principal harbor for inter-island shipping. The percent component values are similar to those that have been determined on ocean-exposed reef areas elsewhere in the Hawaiian Islands but the harbor value is well below the values in other Hawaiian harbors that are more isolated from open ocean circulation than Kaumalapau Harbor. No invasive introduced algae and only two invasive introduced invertebrates were found on the surveys. These were a single colony of the octocoral Carijoa riisei in the vicinity of Cathedrals between Manele Bay and Harbor, and a single stomatopod Gonodactylaceous falcatus at the site closest to Manele Harbor.

Collections and observations in 2002-2003 at harbor and nearby reef sites at Nawilwili and Port Allen, Kauai; Hale O Lono and Kaunakakai, Molokai; Kahului and Maalaea, Maui; and Kawaihae and Hilo, Hawaii recorded a total of 1039 taxa of marine algae, invertebrates, and fishes, 872 of which were identified to the species level. Of these 11 were new reports for Hawaii and 112 were identified as introduced or cryptogenic species (NIS), for an overall NIS component of 10.9% of the total taxa recorded. Contrasting patterns were found between the distributions of the total identified taxa and NIS, with greater numbers of total taxa occurring at reef stations and greater numbers of NIS occurring in harbors, where they composed up to 36% of the total identified taxa. Occurrence and abundance of NIS decreased systematically from maxima in highly used commercial harbors which are isolated from oceanic circulation to relatively exposed small boat harbors to fully exposed reef sites. Only a few NIS that frequently occurred at harbor sites also occurred at reef sites. These results concur with previous studies in Hawaii and the tropical Pacific that have indicated NIS to show maximum numbers in harbors and embayments with restricted oceanic circulation and few introduced or cryptogenic species to occur on coral reefs or other ocean exposed environments.