Research Repository :: Browsing by Author "Muhando, Christopher A."

Browsing by Author "Muhando, Christopher A."

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Calibration of Community-based Coral Reef Monitoring Protocols: Tanzanian Case Study
(WIOMSA, 2010) Muhando, Christopher A.
Abstract—Coral reef monitoring (CRM) has been recognised as an important management tool and has consequently been incorporated in Integrated Coastal Area Management (ICAM) programmes in the Western Indian Ocean (WIO). Community-based coral reef monitoring (CB-CRM), which uses simplified procedures suitable for local conditions, was introduced in Tanzania in 1996. Despite its widespread use, the method has not been calibrated and the validity of merging CB-CRM results with those gained using other techniques has not been determined. In this study, CB-CRM protocols adopted by the Tanga Coastal Zone Conservation and Development Programme (TCZCDP) were tested against SCUBA-based coral reef monitoring (SB-CRM) as practiced by the Institute of Marine Sciences, University of Dar es Salaam. Calibration showed no significant differences in measuring percent cover of live hard corals, sponges, dead corals and substrata (non-biotic cover). However, CB-CRM monitors recorded higher soft coral and lower fleshy algal cover. Larger differences were observed in deeper (>6 m) transects. Counts of sea cucumbers, clams, gastropods and bivalves categories were not significantly different. However, CB-CRM underestimated the abundance of sea urchins, starfish and younger macro-invertebrates in crevices or under overhangs. There were no differences in the identification of reef fish categories but CB-CRM recorded slightly higher reef fish densities than SB-CRM. If properly trained, CB-CRM monitors can generate results that are comparable to those obtained from SB-CRM on shallow reefs. Although a powerful tool which engenders community involvement and a sense of ownership in the sustainable use of coastal resources, CB-CRM has limitations of which managers need to be aware.
Coral Reef Benthos and Fisheries in Tanzania Before and After the 1998 Bleaching and Mortality Event
(WIOMSA, 2002) Muhando, Christopher A.; Mohammed, Mohammed
Abstract—Surveys conducted in the 1980s and early 1990s indicated that coral reefs in Tanzania were being degraded by overexploitation and destructive resource harvesting practices, particularly dynamite fishing and the use of dragnets, with concomitant reduction in fish abundance. Despite reduction in dynamite fishing on most parts of the Tanzania coast, recent coral reef surveys (1999 and 2000) have indicated that live coral cover and the health of reef corals were further degraded by the 1998 coral bleaching event. The extent of coral mortality differed between areas and species. Although the relative contribution of some taxa such as acroporids and pocilloporids decreased on most reefs surveyed, there was no evidence of species extinction. Despite extensive coral mortality, there has been little evidence to suggest decline of reef fish abundance of commercial and artisanal fish catches. In many areas the dead reef structure has remained largely intact three years following the bleaching event. Coral recovery through growth of the surviving colonies and new coral settlement has been observed in all sites, but at different levels. The surviving Montipora, Echinopora and some Fungia were recovering faster than others in some sites. Studies in Mafia, Bagamoyo, Dar es Salaam and Tanga showed that pocilloporids had the highest number of recruits. Faster recovery will, however, depend on the level of natural and human disturbances in the near future. Appropriate reef management strategies, such as enforcement of existing regulations and establishment of more marine protected areas would help to prevent further coral reef degradation. Initiation of coral reef restoration programmes may also enhance the recovery process. Capacity building for coral monitoring/research and appropriate infrastructural support for coral reef ecosystem conservation would also bring noticeable improvement
Coral reef monitoring in Tanzania: an analysis of the last 20 years
(WIOMSA, 2009) Muhando, Christopher A.
Abstract—Coral reef monitoring in Tanzania started in the early 1990s. The main objective was to document reef status and in places assess the extent of damage caused by the use of destructive resource harvesting practices, mainly fishing using dynamite and dragged nets. The information obtained formed the basis for setting up of legislation and control measures and for further monitoring of reef health. Two systems evolved: low tech or simple (skin diving) community-based coral reef monitoring and high tech involving the use of Self Contained Underwater Breathing Apparatus (SCUBA). Coral reef monitoring (CRM) has contributed substantial descriptive information and has raised awareness to coastal communities and managers. Analysis of CRM data over the years has provided information on the dynamics of reef health conditions, e.g. cover and composition of reef benthos, fish and macro-invertebrates. Statistical Power Analysis tests, both on spatial and temporal scales showed inadequate coral monitoring sampling effort, mainly due to high variance of categories being measured. Furthermore, the ongoing monitoring programs did not include environmental or economic indicator variables, hence monitoring results were not linked or statistically analysed against possible causative factors. Lack of information on biological connectivity and vital replenishment factors, e.g., larval sources, dispersal mechanisms, growth, and survival also diluted the interpretation of benthic community data, directly impacting on the strategic management of reef fish and invertebrates. Similarly, the link between socio-economic attributes and coral monitoring results has remained weak. This paper discusses critical issues in the past coral reef monitoring programs and provides strategic recommendations for the next phase of coral reef monitoring in Tanzania
Eastern Africa Atlas of Coastal Resources: Tanzania
(2001) Francis, Julius; Mahongo, Shigalla B.; Semesi, A. K.; Muhando, Christopher A.; Mgaya, Yunus D.; Daffa, J.; Ngoile, Magnus
Ecological Effects of the Crown-of-Thorns Starfish Removal Programme on Chumbe Island Coral Park, Zanzibar, Tanzania
(Ft. Lauderdale, 2008) Muhando, Christopher A.; Lanshammar, F
Abstract. Data on reef benthos has been annually collected on Chumbe, Bawe and Changuu reefs close to Zanzibar, Stone Town, since 1992. The data shows that the El Niño in the Indian Ocean in 1997/1998 reduced the coral cover on most reefs with up to 30%. After the El Niño, a slow recovery was noticed until a major Crown-of-Thorn Starfish (COTS) outbreak occurred in 2002/2003 followed by a dramatic decrease in live Acropora cover. Only one of the reefs shows an exception – the protected Marine Sanctuary on the western side of Chumbe Island. When the first COTS were seen, the park management immediately initiated an on-going COTS removal programme, which has had a significant positive impact on the reef recovery. On the protected reef, the percent cover of live coral is back on the same level as before the bleaching event. Manual COTS removal programmes are often seen as a waste of time and resources, as their impact are often short term. But the results from this study argue that in a relatively small reef area it is a viable option for maintained or increased reef health and for improving recovery prospects of coral after large natural disturbances
Effects of Climate and Seawater Temperature Variation on Coral Bleaching and Mortality
(Ecological Society of America, 2007) Mcclanahan, Timothy; Ateweberhan, Mebrahtu; Muhando, Christopher A.; Maina, Joseph; Mohammed, Mohammed
Coral bleaching due to thermal and environmental stress threatens coral reefs and possibly people who rely on their resources. Here we explore patterns of coral bleaching and mortality in East Africa in 1998 and 2005 in a region where the equatorial current and the island effect of Madagascar interact to create different thermal and physicochemical environments. A variety of temperature statistics were calculated, and their relationships with the degree-heating months (DHM), a good predictor of coral bleaching, determined. Changes in coral cover were analyzed from 29 sites that span .1000 km of coastline from Kenya to the Comoros Islands. Temperature patterns are influenced by the island effect, and there are three main temperature environments based on the rise in temperature over 52 years, measures of temperature variation, and DHM. Offshore sites north of Madagascar that included the Comoros had low temperature rises, low DHM, high standard deviations (SD), and the lowest relative coral mortality. Coastal sites in Kenya had moderate temperature rises, the lowest temperature SD, high DHM, and the highest relative coral mortality. Coastal sites in the south had the highest temperature rises, moderate SD and DHM, and low relative coral mortality. Consequently, the rate of temperature rise was less important than background variation, as reflected by SD and kurtosis measures of sea surface water temperature (SST), in predicting coral survival across 1998. Coral bleaching responses to a warm-water anomaly in 2005 were also negatively related to temperature variation, but positively correlated with the speed of water flow. Separating these effects is difficult; however, both factors will be associated with current environments on the opposite sides of reefs and islands. Reefs in current shadows may represent refugia where corals acclimate and adapt to environmental variation, which better prepares them for rising temperature and anomalies, even though these sites are likely to experience the fastest rates of temperature rise. We suggest that these sites are a conservation priority and should be targeted for management and further ecological research in order to understand acclimation, adaptation, and resilience to climate change
Environmental Effects on the Distribution of Corallimorpharians in Tanzania
(Royal Swedish Academy of Sciences, 2002) Muhando, Christopher A.; Kuguru, Baraka; Wagner, Gregory; Mbije, Nsajigwa; Öhman, Marcus
This study examined the distribution and abundance of corallimorpharians (Cnidaria, Anthozoa) in Tanzania in relation to different aspects of the coral reef environment. Five reefs under varying degrees of human disturbance were investigated using the line intercept transect and point technique. Corallimorpharian growth and the composition of the substratum were quantified in different habitats within reefs: the inner and middle reef flat, the reef crest, and at the 2 and 4 m depths on the reef slope. Corallimorpharians occurred on all the reefs and 5 species were identified: Rhodactis rhodostoma, R. mussoides, Ricordea yuma, Actinodiscus unguja and A. nummiforme. R. rhodostoma was the dominant corallimorpharian at all sites. Within reefs, they had the highest densities in the shallow habitats. While R. rhodostoma occurred in all habitats, the other corallimorpharian species showed uneven distributions. Corallimorpharians ranked second, after scleractinian coral, in percent living cover. Results from this study suggested that corallimorpharians benefitted from disturbance compared with other sessile organisms. They preferred inhabiting areas with dead coral, rock and rubble whilst live coral was avoided. There was a positive relationship between percent cover of corallimorpharians and water turbidity and they dominated the more disturbed reefs, i.e. reefs that were affected by higher nutrient loads and fishing.
The evolving western indian ocean coral reef programme
(Int coral reef sym, 1997) salm, R; Mthiga, N; Muhando, Christopher A.
The region has all reef types from atolls to fringing reefs with many endemic species shared within the Western Indian Ocean (WIO), which suggests that the reefs are linked by currents to make this a discrete biogeographic region. This also means there is a need for regional collaboration among the ten WIO states to manage these reefs. Reef management is not well developed in the WIO, and is focused at the site rather than at national or regional levels. Poorly regulated fisheries and coastal development, together with increasing populations and tourism are major contributors to reef destruction. This is ironic, as both fisheries and coastal tourism are heavily dependent on healthy coral reefs, and make major contributions to the economies of most countries. Many of the reefs in the region are showing distinct signs of damage from human activities, and bleaching in 1998 has been particularly severe in the Seychelles and Kenya. The principal reef management activity is the establishment.....
Impact of hydrographic parameters and seasonal variation in sediment fluxes on coral status at Chumbe and Bawe reefs, Zanzibar, Tanzania
(Elsevier, 2010) Muzuka, Alfred; Dubi, Alfonse M.; Muhando, Christopher A.; Shaghude, Yohanna W.
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
Impact of hydrographic parameters and seasonal variation in sediment fluxes on coral status at Chumbe and Bawe reefs, Zanzibar, Tanzania
(Elsevier, 2010) Muzuka, Alfred; Dubi, Alfonse M.; Muhando, Christopher A.; Shaghude, Yohanna W.
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
Impact of hydrographic parameters and seasonal variation in sediment fluxes on coral status at Chumbe and Bawe reefs, Zanzibar, Tanzania
(Elsevier, 2010) Muzuka, Alfred N. N.; Dubi, Alfonse M.; Muhando, Christopher A.; Shaghude, Yohanna W.
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.
Lunar, diel, and tidal changes in fish assemblages in an East African marine reserve
(Elsevier, 2016) Kruse, Maren; Taylor, Marc; Muhando, Christopher A.; Reuter, Hauke
Fish assemblages in tropical habitats like coral reefs or seagrass beds vary with natural cycles (e.g., lunar, diel or tidal) on several spatio-temporal scales. However, the dimensions of these variations are rarely being quantified despite their strong implications for ecosystem functioning and conservation of exploited stocks. Ignoring these predictable changes hinders the identification of structuring forces of fish assemblages and may lead to incorrect interpretations of the results and evaluation of habitats. To assess natural variation on short timescales, fish assemblages at a small tropical island (Chumbe Island, Tanzania) in the western Indo-Pacific were investigated and compared among two coastal habitats (coral reef and seagrass bed) at different lunar, diel, and tidal phases using underwater visual census methods. Results of multivariate analyses suggested two distinct fish communities in the two habitat types with the coral reef comprising a higher species richness and heterogeneity than the seagrass bed. In the coral reef, community composition and trophic diversity was influenced by all three natural cycles, while in the seagrass bed they were mainly driven by tidal phases. Mean fish densities were slightly different in the two habitat types during daytime but increased significantly in the seagrass bed during twilight hours. For the investigated habitats on Chumbe Island our results indicate that (i) through their routine migrations mobile fishes can provide important functional links between habitats, (ii) seagrass beds have lower species richness and diversity, and emphasize that (iii) fish movement governed by natural cycles can cause predictable short-term variations in fish communities.
Simple and effective monitoring of historic changes in nearshore environments using the free archive of Landsat imagery
(Elsevier, 2009) Knudby, Anders; Newmanb, Candace; Shaghude, Yohanna W.; Muhando, Christopher A.
The recently released archive of Landsat imagery can be used to detect historic changes in nearshore environments. We used a series of free Landsat images spanning the years from 1984 to 2009 to detect changes in the spatial extent of dominant substrate types, coral, algae, and seagrass, around Bawe and Chumbe islands in Zanzibar, and we compared the use of true-colour composites and supervised classifications. Results indicate temporal changes in the spatial extent of seagrass meadows are easily mapped with Landsat imagery, whereas temporal changes in algae cover and particularly coral cover pose greater challenges because of the similarities in spectral reflectance properties between the relevant substrate types. Supervised classification requires substantially more processing than the simple display of true-colour composites, but does not improve interpretation in our study. We suggest that historic Landsat imagery, obtained at no cost and processedminimally with free software, is the best available data source for studies of historic changes in the nearshore environments of East Africa. 2009 Elsevier B.V. All rights reserved
Simple and effective monitoring of historic changes in nearshore environments using the free archive of Landsat imagery
(Elsevier, 2010) Knudby, Anders; Newman, Candace; Shaghude, Yohanna W.; Muhando, Christopher A.
The recently released archive of Landsat imagery can be used to detect historic changes in nearshore environments. We used a series of free Landsat images spanning the years from 1984 to 2009 to detect changes in the spatial extent of dominant substrate types, coral, algae, and seagrass, around Bawe and Chumbe islands in Zanzibar, and we compared the use of true-colour composites and supervised classifications. Results indicate temporal changes in the spatial extent of seagrass meadows are easily mapped with Landsat imagery, whereas temporal changes in algae cover and particularly coral cover pose greater challenges because of the similarities in spectral reflectance properties between the relevant substrate types. Supervised classification requires substantially more processing than the simple display of true-colour composites, but does not improve interpretation in our study. We suggest that historic Landsat imagery, obtained at no cost and processedminimally with free software, is the best available data source for studies of historic changes in the nearshore environments of East Africa.
The Status of Coral Reefs in the Dar-Es-Salaam Marine Reserves System and the State of Reefs in Other Marine Protected Areas of Tanzania
(2000) Muhando, Christopher A.; Francis, Julius
Executive summary Studies dating to the 1960s revealed that the marine environment and its resources are over-exploited and in need of management. The establishment of Dar-es-Salaam marine protected areas (MPA) was adopted by the Government, in 1975, as one of the options to facilitate sustainable utilization of the environment and resources in specified areas. Since coral reefs play a crucial role in the ecology and socio-economy of most MPA in Tanzania, sustainable use of coral reefs has always been an important goal of MPA management. Due to the narrowness of the continental shelf, the majority of the reefs are close to land, as a result they are strongly subjected to human influences and natural calamities. While coral reef studies in the 1960s and 1970s reported high diversity and luxurious growth of corals and associated resources, surveys in the 1980s and 1990s described a general degradation of coral reef ecosystems, mainly due to destructive fishing (dynamite and dragnets) and over-exploitation of certain species key species. Increase in coastal populations, poor economy (lack of alternative employment), unplanned tourism and coastal construction as well as lack of trained personnel and resources to enforce legislation have contributed towards coral reef degradation. The coral reef environment in the Dar-es-Salaam Marine Reserve System, which includes: Mbudya Marine Reserve, Bongoyo Marine Reserve, Pangavini Marine Reserve and Fungu Yasini Marine Reserve, was reported to be so degraded that some scientists questioned whether it was worth maintaining them as a MPA. In addition, Coral reef degradation was reported for reefs in Tanga, Mafia, Songosongo, Mnazi Bay and Msimbati Bay in Mtwara.
The Status of the Coral Reefs of Zanzibar: One Example of a Regional Predicament
(1998) Johnstone, Ron W.; Muhando, Christopher A.; Francis, Julius
Coral reefs are an important resource base for many coastal communities throughout the Western Indian Ocean region (WIO). With the continued growth of coastal populations and the concomitant increase in the need for marine resources, coral reefs stand at the face of overexploitation in many countries, and are being subjected to widespread degradation due to destructive fishing practices and pollution. Within this setting, the islands of Zanzibar exhibit almost all of the problems seen throughout the WIO, and so serve to exemplify some of the issues involved. Zanzibar has extensive coral reefs, which are actively used as a resource base by an increasing coastal population. At the same time, the expansion of urban areas and the development of coastal tourist facilities means that the coral reefs are coming under increasing pressure to provide even more resources than they have historically been required to deliver. At the same time, they are recipients of increasing levels of pollutants from expanding human populations, and they are subject to a range of physically destructive activities. In general terms, the reefs of Zanzibar are in comparatively good condition although there are clear areas of significant perturbation adjacent to certain urban areas and areas of high visitation. The main anthropogenic threats to the coral reefs of Zanzibar include overexploitation, destructive activities (fishing and anchor damage), and pollution. There are indications that overfishing of key species may be leading to a decline in certain economic species as well as ecological shifts in the benthic communities of some reef areas. As is often the case regionally, the lack of historical data limits attempts to resolve the true impact of some of these factors. In line with perceived local problems, a number of activities have been undertaken in Zanzibar to address specific coral-reef related issues, and these are discussed here in the light of the larger regional setting. Some discussion is also centered around the basic issues that undermine the sustainable management of coral reefs in Zanzibar, and how these problems are being dealt with in other parts of the WIO.

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