Ecological evaluation of coral reef resources at Kahalu'u Bay, Hawaiʻi

Abstract

The primary objectives of this research were to: assess coral reef resources (coral and fish communities) present at Kahalu´u Bay, Hawai´i; and integrate scientific ecological observations with Traditional Environmental Knowledge (TEK) and cultural practices. This localized assessment is the first to date at Kahalu'u Bay where continuous coverage of data in a variety of habitats were assessed and mapped at such a small spatial scale. The major results of this research include: the identification of abiotic and biotic factors that influence the abundance and distribution of coral and fish communities at Kahalu´u Bay, and the identification of TEK significance in providing insights into western science, in particular marine ecology. Research findings indicated that the spatial patterns of corals were not regulated by a sole factor. Instead, a combination of factors, which included depth and salinity, significantly explain the variance in coral community structure. Depth is an important factor at Kahalu´u as shallower depths are subjected to heavy human usage, which includes coral trampling. Analogous patterns exist for fishes, where both abiotic (depth, temperature, salinity, pH, location, shelf, sand, and rubble) and biotic (turf, macroalgal, and coral coverage) variables significantly influence fish biomass and numerical abundance (total fish and by trophic level). The impacts of abiotic factors are based on species thresholds. Individual biotic requirements of all fish and by trophic level are influenced by space or shelter availability and food. Differences in abiotic and biotic preferences between trophic levels were observed. Understanding factors affecting fish communities is important in the development of future protected areas. Traditional Environmental Knowledge was acquired and rigorously tested statistically. Results indicated that TEK, based on environmental observations, gathered by the kūpuna were identical to other findings that are published in the primary literature which were based on western science protocol. Findings support the importance of integrating western science and TEK. This study provides the baseline for future monitoring and assessment of coral reef resources. Moreover research findings will be crucial in future resource management. With the integration of TEK and western science, a holistic approach can be used to make sound decision concerning reef resources.