Coral reef monitoring in Tanzania: an analysis of the last 20 years

Abstract—Coral reef monitoring in Tanzania started in the early 1990s. The main objective was to document reef status and in places assess the extent of damage caused by the use of destructive resource harvesting practices, mainly fishing using dynamite and dragged nets. The information obtained formed the basis for setting up of legislation and control measures and for further monitoring of reef health. Two systems evolved: low tech or simple (skin diving) community-based coral reef monitoring and high tech involving the use of Self Contained Underwater Breathing Apparatus (SCUBA). Coral reef monitoring (CRM) has contributed substantial descriptive information and has raised awareness to coastal communities and managers. Analysis of CRM data over the years has provided information on the dynamics of reef health conditions, e.g. cover and composition of reef benthos, fish and macro-invertebrates. Statistical Power Analysis tests, both on spatial and temporal scales showed inadequate coral monitoring sampling effort, mainly due to high variance of categories being measured. Furthermore, the ongoing monitoring programs did not include environmental or economic indicator variables, hence monitoring results were not linked or statistically analysed against possible causative factors. Lack of information on biological connectivity and vital replenishment factors, e.g., larval sources, dispersal mechanisms, growth, and survival also diluted the interpretation of benthic community data, directly impacting on the strategic management of reef fish and invertebrates. Similarly, the link between socio-economic attributes and coral monitoring results has remained weak. This paper discusses critical issues in the past coral reef monitoring programs and provides strategic recommendations for the next phase of coral reef monitoring in Tanzania.