This technical report is part of the FAO-TZ project “Support to Seaweed Diseases and Die-off Understanding and Eradication in Zanzibar” TCP/URT/3601/C1. It covers an initial analysis of the die-offs due to epiphyte infestation and ice-ice disease in Zanzibar. The assessment is mainly based on site visits to the seaweed farms in Unguja and Pemba and laboratorial analysis of collected seaweed samples.