Muzuka, Alfred; Dubi, Alfonse; Muhando, Christopher A.; Shaghude, Yohanna W.
Description:
Coral reefs which are an important resource to coastal communities and nation at large are adversely
affected by rate of sediment flux to the reefs. However, there is little information on seasonal trend in
sediment flux and its impact at the reefs off Zanzibar. Two years’ monthly data on sedimentation at
Chumbe and Bawe reefs were used to assess seasonal variability in sediment flux and its implication on
the coral status. Sediment flux to the Bawe reefs for the duration of the study ranged from 0.2 to
41.5 mg cm 2 d 1, while it ranged from 0.8 to 65.8 mg cm 2 d 1 at the Chumbe reefs. Sediment fluxes at
Bawe reefs were highest between November and March, while they were highest between April and
September at Chumbe reefs. Generally, sediment fluxes at Bawe reefs were low compared to those at
Chumbe. The total sediment input to the reefs ranged from 4615 to 123,403 kg d 1 for Bawe reefs and
2750 to 79,636 kg d 1 for Chumbe reefs. High sediment fluxes at Bawe reefs between November and
March; and the Chumbe reefs between April and September can be attributed to water currents
and wind pattern in the east African region which are under the influence of the monsoons. The observed
trend suggests that the period for coral transplant as a management option for the two sites should be
different. Coral transplant can be undertaken in such a way that stress of the corals due to sedimentation
can be felt after they have overcome stress from transplant process and temperature. The results from
this study contribute to the much needed information for coral transplant, restoration, and management