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Middlebury College

Publication Date

Fall 2018

Program Name

Tanzania-Zanzibar: Coastal Ecology and Natural Resource Management


A survey of six common grouper (Serranidae) species was conducted on both the western protected and eastern unprotected reefs around Chumbe Island. Species, estimated maturity, and fundamental niche and general habitat preference was extrapolated based on observed realized niche and qualified according to substrate, depth, slope position, and general reef region. Abundance, biomass density, and biodiversity of Serranid populations were compared among locations on the reef with habitat preference in mind in order to best assess how habitat influences population composition, distribution, and health. The results of this study provide depth to previous research on the protected reef and indicate noteworthy shifts in population composition between 2014 and 2018 in favor of species with less specified habitat preference and subsequently wider ranges. Thus, this study suggests that Serranid populations around Chumbe Island are experiencing a regime shift in response to the degradation of their coral reef habitat. Surveys of Chumbe’s nearby unprotected eastern reef indicate low levels of species abundance, which are hypothesized to be the result of inappropriate habitat structure, increased fishing pressure, and decreased population health within the MPA. Ultimately, this study suggests that monitoring Serranid populations collectively in terms of abundance and without heed to species does not effectively measure population health. Indeed, research of reef dependent fishes that does not take habitat into consideration fail to capture, explain, and inform management of changes in marine populations and the habitats they are intrinsically linked to as a result of a threat that cannot be mitigated even by an MPA – climate change.


African Studies | Aquaculture and Fisheries | Environmental Indicators and Impact Assessment | Environmental Monitoring | Marine Biology | Oceanography


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