Responses of marine fouling communities to sewage abatement in Kaneohe Bay,Oahu, Hawaii

The development of marine fouling communities was followed as part of a sewage abatement study in Kaneohe Bay (Oahu, Hawaii). Panels immersed near the outfall during sewage discharge were dominated by dense mats of blue-green algae and diatoms. This mat was significantly lighter at this station when sewage did not flow into the bay, and it never developed on panels within the same sector of the bay but away from the influence of the outfall. Taxonomic diversity, and the frequency of filamentous algae and the serpulidHydroides elegans were reduced near the outfall during discharge. It is suggested that this reduction in diversity and abundance of certain key foulers is due to competitive exclusion by the dense blue-green and diatom mats, and is not a direct effect of the sewage effluent.