Impacts of Sea Surface Temperature on Coral Reefs in Mafia Island, Tanzania

Abstract

Coral reefs are very sensitive and vulnerable to Sea Surface Temperature (SST) rise than their optimal maximum temperature (27°C). SST rise do not only affect coral reef but also fishery production. Line Intersect Transect (LIT) and key informant interview have been used to study the effect of SST on coral reefs in Chole bay and Jibondo in Mafia Island. Sea Surface temperature in Mafia has increased by 0.56°C since 2001 up to 2016. This increase has significant effect on coral reef health, as it causes coral bleaching and reduction of fish catch. In Mafia Island increase in SST from November 2015 up to April 2016 was exacerbated by El Nino incidence in the Indian Ocean. The El Nino incidence was very strong with the temperature rise of 2.3°C. Almost 50% of coral reefs in Mafia have been bleached in 2016 while from 2001 bleaching varied in yearly basis. That's, coral reefs tend to bleach from January to March in every year and recover from September to November in every year, but the 2016 bleaching incidence was very severe since, 40-60% was bleached in mafia Island.