One year at Honu'apo Bay: A social and biological monitoring project in SE Hawai'i (Ka'u)

A one year study combining social and biological sciences was conducted at Honu'apo Bay, Hawai'i Island [Ka'u District] from Fall 2008 to 2009. The fishes inhabiting the nearshore waters of Honu'apo Bay were monitored over a period of 13 months starting with the full moon in November 2008. Surveys were conducted on 26 occasions around every new and full moon (semilunar sampling) in an attempt to identify any seasonal or lunar patterns in fish structure and assemblage. The benthic environment and various water quality characteristics were also monitored. At the same time, human usage was documented for the area and 174 social surveys were distributed to local residents. Of the 57,771 fishes and 79 species that were surveyed, the average total length was 5 cm. Juvenile fishes made up the majority of the fish population (82.6% relative abundance) for all transects and surveys. In general for Honu'apo, juvenile fishes were more abundant during the dry season, and biomass values for all fishes were greater during the wet season. Other factors that were found to be significant in structuring fish-assemblage characteristics (abundance, species richness, and biomass) included turbidity, pen shell (Pinna muricata) abundance, and transect location. Percentage sand cover and bottom-water specific gravity were also significant factors for species richness, and temperature was a significant factor for biomass. Moon phase was only significant when transect location was included in the model (in which case, slightly more fishes were counted during new moon surveys). Otherwise, temperature, salinity and rugosity were not found to be significant predictors for fish distribution. Sociocultural results revealed moderate fishing pressure along the shore and identified 29 targeted resource species. Social survey results from island residents indicate strong support for conservation efforts along the Ka'u coastline. In addition, several options are discussed for marine management tools for Honu'apo Bay and its marine biota.;Keywords. Coral reef, Fish, Juvenile, Ecology, Hawai'i, Community-based management, Seasonality, Turbidity...