Effects of turbidity on shallow-water reef fish assemblages in Truk, Eastern Caroline islands

Abstract

Reef fish assemblages were monitored annually from 1978 to 1981 at a series of stations adjacent to an airport runway construction site on Moen, Truk. Monitoring began prior to construction activities and continued through three years during which dredging and filling of adjacent reef areas took place. As a result of construction activities, large amounts of sediments were released into the water. Turbidity was measured monthly throughout the period of the fish monitoring and showed considerable variation from station to station. Fish abundance and diversity were significantly reduced at stations which were inundated with fine sediments. However, at stations at which sediment did not accumulate, fish assemblages remained reasonably stable, even under conditions of high water turbidity. The value of using reef fish as indicators of early stages of environmental degradation is discussed.