Fauna Census of Intertidal Cliffs, Mangapwani, Zanzibar

Class Year


Document Type

Student Research Paper

Date of Creation

Spring 2015

Department 1

Center for Global Education


Due to their extreme variations in condition over the course of a day, intertidal zones are challenging environments. Organisms that live there must be prepared to cope with both exposure and submersion, not to mention the temperature variations that accompany these conditions. The differing tolerances and adaptations of various organisms to these conditions generally cause patterns of vertical zonation to occur in the intertidal zone, especially when the shore is steep and rocky. Understanding the ecology of shore environments is important to future conservation and management efforts. This study was conducted on a beach in Mangapwani, Zanzibar at at 6˚ 9.874’S and 39˚ 11.281’E. In order to establish what organisms make use of steep, rocky, intertidal habitats in Zanzibar and establish a baseline understanding of the ecosystem with which to compare future changes, a census was taken of the animals living on the intertidal sections of cliffs and steep rock faces and data was analyzed for evidence of vertical zonation patterns. Informal observations of human activity were also made to gauge the likely level of anthropogenic impact already occurring at the site. From April 6 through April 23, organisms were identified and counted along 11 transects with between six and 11 replicates per transect location. Nineteen different kinds of organisms from three phyla (Chordata, Crustacea, Mollusca) were observed over the course of this study. The most numerous animals were acorn barnacles (Chthamalus dentatus), conical barnacles (Tetraclita squamosal rufotincta), limpets (Phylum Mollusca, Family Patellidae), and mussels (Phylum Mollusca, Family Mytilidae). These organisms were all very likely to exhibit distribution patterns along a transect that were found to be significantly inconsistent with random distribution.

This paper was written for the Tanzania-Zanzibar: Coastal Ecology and Natural Resource Management program.