Meeting Abstract

38.1  Saturday, Jan. 5  Water Quality of Kāne'ohe Bay Using Indicator Species Tripneustes Gratilla THOMAS, W H*; FUNG, J K; THOMAS, F; University of Hawai'i- Windward Community College

Over the years the populations of the sea urchin Tripneustes gratilla have decreased drastically in Kāne'ohe Bay, Hawaii. The loss of this opportunistic grazer from its waters has coincided with an increase in invasive algal species like Gracilaria salicornia that impact the coral reef ecosystem. The goal of this study was to measure the water quality of Kāneʻohe Bay by tracking the effect of naturally occurring waters from off shore and near shore sites on early development in T. gratilla . The results of these experiments were compared to a reference toxicant (copper) over a range of concentrations. A gamete-extraction protocol was performed to produce fertilized urchin eggs. The urchin embryos were allowed to grow in 20 mL beakers of onshore, offshore, and control seawater, and seawater containing varying concentrations of copper. Concentrations range from 5 μg per liter to 200 μg per liter. Larvae were allowed to develop for three days. After which tallies were taken to see how the larvae developed. The larvae were categorized as normal, abnormal or underdeveloped. In the copper-toxicity test, urchin larvae showed sensitivity to copper above concentration of 20μg per liter, with normal development dropping to 30 % normal development at this concentration. In naturally occurring water, samples from onshore had more underdeveloped and abnormal larvae than those developing in offshore water samples. The onshore samples had similar levels of abnormal and underdeveloped larvae to concentrations of copper ranging from 20 μg per liter to 200 μg per liter. This could mean that chemicals with properties similar to those of copper are in high concentration along the shores of Kāne'ohe Bay.