Floating Island of Trees and Myths: The Rare 2022 Nzera Bay Event in Lake Victoria

Floating islands are not unique to Lake Victoria. Their recurrence reflects underlying hydrological and ecological processes linked to seasonal variability in lake water levels, which can facilitate their detachment and mobility, rather than superstition or unexplained forces. In April 2022, a rare and unusual large floating island appeared in Nzera Bay, Lake Victoria, near Kahunda village, captivating the Tanzanian public and prompting scientific investigation. Unlike typical papyrus mats, this island supported large trees, marshes, emergent macrophytes, and diverse fauna, including birds and reptiles. A multidisciplinary team was formed to investigate the island’s origin, composition, movement, and cultural significance. Field surveys and GIS-based satellite tracking revealed that the island detached from wetland vegetation near Kasheka village between 15–20 April 2022, likely due to a combination of persistent strong winds, waves and elevated water levels following prolonged drought and heavy rains. Morphometric analysis estimated the island’s area at 7.1 hectares, with an average soil thickness of 2 meters. Vegetation surveys identified 27 plant species, including three tree species and a ground orchid of conservation concern ( Eulophiaangolensis ). Soil samples showed high organic content, suggesting buoyancy-enhancing decomposition processes. Ethnographic interviews highlighted traditional beliefs, medicinal uses, and ritual practices linked to floating islands. Although floating islands contribute ecological benefits, their movement poses threats to navigation, fisheries, and cage farming in their path. This study provides scientific insights and offers management recommendations, including harvesting for organic compost and spatial monitoring, to mitigate potential impacts in Lake Victoria.