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Harvey Mudd College

Publication Date

Spring 2006

Program Name

Tanzania-Zanzibar: Coastal Ecology and Natural Resource Management


The populations of sea urchins and their main predators, triggerfish (Balistidae), wrasses (Labridae) and emperors (Lethrinidae), were studied in the extractive and non-extractive zones of the Misali Island Marine Conservation Area in order to (1) evaluate the applicability of a sea urchin-sea urchin predator model developed in Kenya’s fringing reefs, (2) gain baseline data on Misali’s coral reef, and (3) evaluate the recovery status of the protected zone. This study revealed the predictive power of the sea urchin-sea urchin predator model for the reef ecosystem of Misali Island. As expected, a decline in sea urchin predators as a gross trophic group was attributable to fishing pressure and corresponded with an increase in sea urchin density. Furthermore, a comparison between the sea urchin predator species of the non-extractive and extractive zones showed that the proportion of triggerfish, which studies have suggested to be the dominant sea urchin predator, has increased in the absence of fishing as expected (McClanahan, 2000).


Aquaculture and Fisheries | Natural Resources and Conservation | Oceanography


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