Fig. 1

Map showing study locations. The three study islands are located in Lake Victoria, western Kenya. Mageta and Magare are located in Siaya County, while Ngodhe is in Homa Bay County. Areas of Mageta, Magare and Ngodhe are 7.02, 0.20 and 0.90 sq km, respectively. The distance between Mageta and Magare Islands is about 0.30, which are about 28.5 km north-west of Ngodhe Island