Unique siphon openings formed by Lingula reevii burrows. Abstract The inarticulated brachiopod, Lingula reevii, is listed as a National Oceanic and Atmospheric Association (NOAA) National Marine Fisheries Service (NMFS) Species of Concern (SOC). In the late 1960s, estimates of the L. reevii population within Kaneohe Bay on the Island of Oahu, Hawaii were as high as 500 individuals/m 2 in the southern areas of the bay (Worcester 1969). Successive surveys of the bay revealed declining population size of L. reevii with the lowest observed maximum density recorded in 2009 (0.09 individuals/m².) Despite past trends, the current study (July, 2010) found a larger L. reevii maximum density of 2.93 individuals/m². Although previous surveys have attributed the population decline to high levels of invasive algae cover, this study found no significant relationships between macroalgal cover and the densities of this species. It may be that macroalgae declined in the areas examined from 2009-2010, resulting in this finding. Other environmental parameters (temperature, water depth, sediment depth, salinity, and seagrass cover) were quantified and compared to the current densities of L. reevii in Kaneohe Bay; none showed significant relationships.