Grey's Beach Infauna Study of Source Dredge Sand Off Waikiki

Abstract

A diverse assemblage of infaunal polychaetes and invertebrates was collected in three replicate sand samples from three locations off Grey’s Beach, Waikīkī, O’ahu, Hawai’i. Infauna were extracted over 0.5 mm and 0.25 mm sieves. Specimens from the 0.5 mm fraction were identified and enumerated while those from the 0.25 fraction were qualitatively assessed. Nematodes were the most numerous specimens collected, followed by oligochaetes and harpacticoid copepods. Polychaetes ranked fourth in abundance followed by lesser abundances of thirteen other taxa. The 45 polychaetes were assigned to 15 taxa. The outside station had the highest taxonomic richness compared to both stations within the source-sand area. Polychaetes were predominantly motile, free-living taxa with an omnivorous feeding mode. The second-most-collected taxa were detritivores. Tube-dwelling species were not collected in these samples. Reproduction was evident in only two polychaete individuals of different species. None of the invertebrates collected were unusual or rare in their distribution in shallow Hawaiian sands.