A preliminary study into the potential of mayflies (Ephemeroptera: Baetidae and Caenidae) as bio-indicators of stream health in Fiji

Abstract

flowing through an area of tropical lowland rainfor est and urban streams running through residential and indus trial areas. The two rural streams were Waisila Stream l ocated within the Colo-I-Suva Forest Reserve approximately 6 km from Suva and the Savura water catchment within the forested area of the upper Wailoku River. The two urban streams were the Nabua stream where it runs through an army barracks and the Nabukalou creek running directly through Suva city centre. Mayfly nymphs were sampled from riffles in each stream by lifting ten rocks and vigorously brushing the surface of each with a soft brush while a fine-mesh net was held down stream. All mayfly nymph specimens were preserved in 80% ethanol until being examined under a dissecting microscope and identified to family leve l according to Dean and Suter (1996). Five samples of nymphs were collected from five replicate sites in each stream (approximately 10m of stream length) on each stream. The samples collected within each site wer e then pooled.