Land-based Pollutants in Hawaiian Reef Fishes and Sediment

In this study we explored the relationship between land use and reef fishes in Hawaiʻi by examining the concentrations of different metals in sediments and in the tissues of fishes spanning multiple trophic levels from sites on Oʻahu and Kauaʻi. We particularly focused on species that are commonly targeted by fishermen. Tissue samples were analyzed for a suite of 21 metals using inductively-coupled mass spectrometry. We detected high levels of arsenic in sediment and in some fish tissues at several locations on Oʻahu and Kauaʻi with historic agriculture. We also found high lead levels in sediment and fish from an urban, industrial coastal area in Honolulu (Kewalo Basin). Sediment and fish samples from a reef adjacent to a residential area of Honolulu (Maunalua) had higher thallium concentrations than samples from other sites, and fish from an industrial harbor on Kauaʻi that also receives agricultural inputs (Hanapepe) had higher zinc and selenium concentrations than those from other locations. Our ongoing work continues to expand this research to better understand the trophic pathways linking land-based pollutants and reef fishes by examining algae and invertebrates, alongside fish and sediment, and we are also incorporating analyses of organic pollutants. We hope our results will help communities and resource managers in Hawaiʻi by providing information on locations and species of potential concern.