Evaluation of Seagrass and Seaweed Species Diversity, Abundance, and Human Activities Endangering their Existence at Indian Ocean Shore at Kigamboni in Dar es Salaam City, Coastal Zone of Tanzania

An evaluation of seagrass and seaweed species diversity, abundance, and the human activities endangering their existence were conducted at the Kigamboni Indian ocean shore in Dar es Salaam city. The study aimed to determine the abundance, diversity of seagrasses and seaweeds and to identify human activities undertaken in the study area. A transect was set within the study area where plots of 10 m x 10 m (100 m2) were established at an interval of 100m. The encountered seagrass and seaweed species were identified for their scientific names to species level and whenever it was not possible, a specimen was collected and taken to the University of Dar es Salaam Herbarium (DSM) for identification. The species were also counted and recorded as per their number of stems. H’ was applied to calculate the Shannon Wiener Index of Diversity. Also, relative abundance (RA) was calculated. A total of 17 species from 14 genera were identified. The calculated H’ was 2.0309, an implication of high seagrass and seaweed species diversity. The identified human activities were fishing and swimming. Of those activities, bait collection (33.89%) was the most dominant while swimming had 33.33%, fishing had 16.67% and marine gravel had 11.11%. Kigamboni ocean shore comprises of high species diversity of seagrass and seaweed species, facing severe damage from human disturbances.  This study recommends for sustainable management of the ocean shore through education, protection strategy to ensure the survival of the existing seagrasses and seaweed species.