Nonindigenous marine species at Waikiki and Hawaii Kai, Oahu, Hawaii

Coles, SL; Defelice, R; Eldredge, L

Surveys of the marine algae, invertebrates and reef fishes of Waikîkî and the Kuapâ Pond and Maunalua Bay areas of Hawai`i Kai were conducted with the objective of the presence and impact of nonindigenous (introduced) marine organisms. Findings were compared with historical records of species reported in these locations and with the results of similar studies conducted in Hawai`i and the Pacific. Observations and collections were made at 15 stations at Waikîkî in January 2001 and at five stations in Kuapâ Pond-Maunalua Bay in February 2002 at 5 stations. A comprehensive literature review of published papers and books and unpublished reports was conducted to develop listings of previous species reports, and the marine invertebrates, fish, mollusk and algae collections at Bishop Museum were queried for information regarding all organisms that had been collected from these areas. The assembled data were developed into a relational data bases used to determine the percent component of the total biota that is nonindigenous or cryptogenic, the number of new reports versus the number of previous reports not found, and a chronology of first reports of introductions. A total of 925 taxa including 749 species were observed or collected in Waikîkî, and 384 taxa including 317 species at Kuapâ Pond-Maunalua Bay. Of these 52 species designated introduced or cryptogenic (collectively termed NIS) were identified at Waikîkî, for an NIS component of 6.9% of the total species identified for the 15 stations. By comparison 58 NIS were observed or collected at Kuapâ Pond-Maunalua Bay amounting to an NIS component of total species of 18%. Forty-six of the 52 NIS were new reports for Waikîkî, and 56 of the 58 NIS new for Kuapâ Pond- Maunalua Bay sites. However, all but three species, hydroids collected from Waikîkî designated cryptogenic, were previously reported elsewhere in Hawai`i, with first reports mostly in Pearl Harbor, Honolulu Harbor or Kane`ohe Bay. The high incidence of first reports for Waikîkî and the Hawai`i Kai area in this study are clearly effort related, since these were the first comprehensive sampling efforts that have been conducted at these locations. At Waikîkî there was little indication of differences in spatial distributions among the 15 stations for the total identified biota, major taxonomic groups of invertebrate or fish species in any or total NIS. However total algal species and algal NIS showed a clear association nearshore stations, especially in the vicinity of the beachfront from the Waikîkî Aquarium to San Souci, where the invasive nonindigenous algae Acanthophora spicifera, Gracilaria salicornia and Hypnea musciformis cover the reef flat and dominate the biota. This area is the most environmentally disturbed at Waikîkî, but overall the benthic environment is highly degraded from the coral reef community that was described early in the 20th century, with few reef corals remaining in very abundance. Overall, the Waikîkî reef has been highly impacted from continual deposition of beach sand along the shoreline that has moved offshore and buried or otherwise impacted reef surfaces, resulting in a mostly sand covered bottom that was dominated by a widespread coverage of the brown alga Dictyopteris australis at the time of our survey. Regarding non-algal NIS that are considered invasive, the mostly widely occurring invertebrate was the stomatopod Gonodactylaceus falcatus, which occurred in low abundance at five stations and the most prominent was the octocoral Carijoa riisei, which covers the interior surfaces of the shipwreck thatwas placed offshore in 30 m depth as a viewing site for the tourist submarine Atlantis. The invasive fish Lutjanus kasmira is also abundant at this site, and a single invasive grouper Cephalopholis argus was sighted at one other station.

Nonindigenous marine species at Waikiki and Hawaii Kai, Oahu, Hawaii

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