Browsing by Author "Semesi, A. K."

Now showing 1 - 6 of 6
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    Coastal resources utilization and conservation issues in Bagamoyo, Tanzania
    (1998) Semesi, A. K.; Mgaya, Yunus D.; Muruke, M. H. S.; Francis, Julius; Mtolera, Matern; Msumi, G.
    A study was carried out to provide information about the importance of the management of coastal resources in Bagamoyo, Tanzania. The results showed that the coral reefs at Mwamba Kuni and Mshingwi are the main fishing grounds for the artisanal fishermen. Trawlers compete and conflict with artisanal fishermen. The mangroves provide habitats for fish and other animals and are a source of fuelwood, charcoal, fishing stakes, building materials, and traditional medicines. Solar salt production is also an important activity. Although Bagamoyo depends on renewable resources, the harvesting rates of most resources are not known. Habitat destruction and overexploitation of resources have resulted in declining catches. There is unawareness among the resource users of the linkages between the various coastal ecosystems, but they do have vast traditional knowledge about the resources. In this article, we present the crustacean resources, fish, sea cucumbers, mangrove products, coral reefs, tourism, and salt production activities.
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    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
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    The Effect of Seasons on Yield And Quality of Carrageenan from Tanzanian Red Alga Eucheuma Denticulatum (Gigartinales, Rhodophyta)
    (Elsevier, 2001-09) Buriyo, Amelia S.; Semesi, A. K.; Mtolera, Matern S. P.
    Samples were collected monthly from Oyster Bay, Dar es Salaam. Light, temperature, salinity, pH, seawater nitrogen and phosphorus were determined on each sampling period. Mean carrageenan yield was significanlly higher during the SE monsoon period (t = 6.15, P<0.05). Gef strength was significantly higher during NE monsoon period (t = 2.61, P<0.05) and lower during the start of the rainy season particularly in March.
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    The Physical and Chemical Characteristics of a Phycocolloid from the Red Alga Sarcodia Montagneana j. Agardh of Tanzania
    (1987) Semesi, A. K.; Banyikwa, Feetham F.
    A phycocolloid from Sarcodia montagneana has been evaluated by chemical and physical analyses. The study has revealed that the phycocolloid has a yield of 39.6 per cent (percentage dry weight of alga), an IR spectrum similar to that reported for .lambda.-type carrageenan, an SO4-2 content of 22.5 per cent, a 3, 6-anhydrogalactose content of 5.1 per cent, a galactose content of 51.5 per cent (percentage dry weight of phycocolloid) and a negative optical rotation. The polysaccharide does not form a gel and cannot be modified by alkaline borohydride. It may be used in the food industry as an emulsifying agent.
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    The Seagrass and Associated Macroalgae at Selected Beaches along Dar Es Salaam Coast
    (2001) Lugendo, Blandina R.; Mgaya, Yunus D.; Semesi, A. K.
    Intertidal seagrasses and macroalgae were studied at a sewage-polluted beach (Ocean Road) and a control site at Kunduchi beach, with a view to assessing the effect of sewage discharge on macrophyte species composition, abundance and above-ground biomass. A total of six species of seagrasses were recorded at Ocean Road of which two, Thalassia hemprichii and Cymodocea rotundata were the most abundant. Eight species of seagrasses were recorded at Kunduchi. Two species, Syringodium isoetifolium and Thalassodendron ciliatum were dominant in areas with strong oceanic influence. Halodule wrightii and Halophila ovalis were widely distributed in the two study areas. The mean biomass of seagrasses between Ocean Road and Kunduchi beaches was not significantly different (z = 4.053; p = 0.001; d.f. = 54). A total of 25 and 24 macroalgae species were recorded at Ocean Road and Kunduchi beaches, respectively. The total biomass of macroalgae was higher at Ocean Road than at Kunduchi (t = 4.838; p>0.001). While the biomass of brown macroalgae was higher at Kunduchi (t = 2.115; p = 0.039), that of red algae was similar at both sites (t = 1.986; p = 0.052). Of the 11 epiphytic species of macroalgae recorded on T. ciliatum at Kunduchi area, 73% were red algae, 18% green algae and 9% brown algae. The dominant species on this beach was the brown alga Cystoseira myrica. It was concluded that elevated levels of ammonium at Ocean Road is a likely cause of the observed higher biomass of green macroalgae at this site.