College of Agricultural Sciences and Fisheries Technology

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. Abundance and diversity of seagrass and macrofauna in the inter-tidal areas with and without seaweed farming activities in the east coast of Zanzibar
(2008) Lyimo, Thomas J.; Mvungi, Esther F.; Mgaya, Yunus D.
The diversity and abundance of seagrass and associated macrofauna were studied in transects with and without seaweed farms at Chwaka Bay and Jambiani, in the East Coast of Zanzibar. Eight seagrass species, namely Cymodocea rotundata, Cymodocea serrulata, Thalassia hemprichii, Thalassodendron ciliatum, Syringodium isoetifolium, Halodule uninervis, Halophila ovalis and Enhalus acoroides were recorded in the transects. The mean total biomass of seagrass at Chwaka Bay ranged from 142.4 ± 70.71 to 1652 ± 772.7 g dw/m2 and 212.9 ± 146.2 to 1829 ± 1692 g dw/m2 in station with and without seaweed farms, respectively. At Jambiani, the mean total biomass ranged from 880.4 ± 336.8 to 3467 ± 549.9 and 203.4 ± 102.4 to 3810 ± 2770 g dw/m2 in station with and without seaweed farms, respectively. The overall total biomass of seagrass was significantly lower (KW = 108.7, p < 0.0001) in station with seaweed farms than in stations without seaweed farms. A total of 93 macrofauna species representing 60 families were encountered and the mean density ranged from 910 to 6990 individuals/m2 at Chwaka Bay and Jambiani in stations with and without seaweed farms respectively. The most common macrofauna species were Codakia punctata, Meropesta nicobarica, Echinometra mathaei, Pinna muricata and Clibanarius emystemus. It was shown that the macrofauna abundance and diversity was higher in stations without seaweed farms than in the stations with seaweed farms, which could be due to activities associated with seaweed farming which contributed to the loss of diversity and biomass of flora and macrofauna of the seagrass meadows.
Analysis of Ground Level Ozone and Nitrogen Oxides in the City of Dar es Salaam and the Rural Area of Bagamoyo, Tanzania
(2015-01) Hamdun, Asha; Arakaki, T.
From 2012 to 2015, we measured surface ozone, NOx, NO2, and NO levels at three urban sites (Ma-pipa, Ubungo, and Posta) and two suburban sites (Kunduchi and Vijibweni) in the city of Dar es Salaam and in the village of Mwetemo, a rural area of Bagamoyo, Tanzania. The average hourly O3 concentrations at all sites were between 9 ppb and 30 ppb during our sampling periods. O3 levels at suburban sites were generally higher than at urban sites. The average hourly concentrations in Dar es Salaam were 10 - 32 ppb, while in Bagamoyo they were 9 - 15 ppb. We observed a strong diurnal variation in Dar es Salaam while measurements from Bagamoyo showed little variation. At Dar es Salaam, the surface O3 concentrations increased from their minimum level at sunrise (around 6:00 a.m.) to a maximum in the late afternoon (around 4:00 p.m.), and then decreased toward 11:00 p.m. Another secondary ozone peak appeared between midnight and ~4:00 a.m., after which the surface ozone concentrations decreased to a minimum around 7:00 a.m. NO2 concentrations were higher at the urban sites of Ubungo and Posta, and their weekly average NO2 concentrations were 246 ppb and 118 ppb, respectively. Weekly average NOx concentrations ranged from 39.4 ppb at the Kunduchi site (suburban) to 738 ppb at the Ubungo site (urban). To our knowledge, there were few continuous measurements of ozone and nitrogen oxides concentrations in Tanza-nia. Since high NOx concentrations were observed, continuous air quality monitoring and effective air pollution control measures are required in Dar es Salaam to prevent further deterioration of air quality and limit the possible negative impacts on humans and vegetation.
Analysis of Rainfall Variations and Trends in Coastal Tanzania
(Western Indian Ocean Journal of Marine Science, 2013-09) Mahongo, Shigalla B.; Francis, Julius
Rainfall in coastal Tanzania has been investigated for their variability and trends from seven key weather stations during the last 50 years (1960-2009). Results indicate that the island of Mafia receives the highest amount of rainfall (1879 mm/yr) while Kilwa Masoko receives the lowest (1029 mm/yr). Generally, precipitation in the islands is heavier than on the mainland coast due to moisture convergence in sea breezes. The monthly series indicate predominance of annual and semi-annual oscillations in the northern sector, while in the southern coast the annual signal is the most dominant. Partial correlation analysis revealed a significant influence of the El-Niño Southern Oscillation (ENSO) on annual rainfall. However, the effects of the Pacific Decadal Oscillation (PDO) and the Indian Ocean Dipole (IOD) are relatively smaller. In the seasonal timescale, the effects of the large scale climatic phenomena are relatively smaller during the rainfall and Northeast (NE) monsoon seasons, but are significantly larger during the Southeast (SE) monsoon. Linear regressions of the monthly rainfall series portray a general downfall trend at each station, but all the trends are insignificant. The inter-annual and decadal variations show that the year 2003 and the last decade (2000-2009) were generally the driest in the last half century.
Anthropogenic Pollution in the Dar es Salaam Harbour Area, Tanzania.
(Elsevier, 1992-11) Machiwa, John F.
Man-made pollutants, namely, petroleum hydrocarbons, polychlorinated biphenyls (PCBs), and heavy metals as well as microbial pollution in the sediments of the harbour channel have been evaluated. Petroleum hydrocarbons, PCBs and heavy metals (Fe, Pb, Cu, and Zn) are at elevated levels in the port area used for loading and unloading activities. The concentration of the chemicals decreases further offshore, with the exception of cadmium which, surprisingly, is enriched in the sediments at the ship outer anchorage zone. The concentration-depth profile of the sediment core samples show that in general metals are uniformly distributed with depth in the sediment. The between station variation of Mn, Cr and Ni is strongly influenced by grain size differences. Total and faecal coliform bacteria are few in the port area but are extremely abundant at the fish landing beach and close to the sewer outfall
Anthropometric Data Collection of the Tanzanian Worker
(1984) Majaja, Bashira A.; Bhandari, V. K.
Antimicrobial Properties and Mechanism of Action of Some Plant Extracts Against Food Pathogens and Spoilage Microorganisms
(Frontiers in Microbiology, 2018-07-24) Gonelimali, Faraja Deo; Jiheng, Lin; Wenhua, Miao; Jinghu, Xuan; Fedrick, Charles; Meiling, Chen; Shaimaa, Hatab R
This work aims to evaluate the antimicrobial potential of ethanolic and water extracts of roselle (Hibiscus sabdariffa), rosemary (Rosmarinus officinalis), clove (Syzygium aromaticum), and thyme (Thymus vulgaris) on some food pathogens and spoilage microorganisms. Agar well diffusion method has been used to determine the antimicrobial activities and minimum inhibitory concentrations (MIC) of different plant extracts against Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus), Gram-negative bacteria (Escherichia coli, Salmonella enteritidis, Vibrio parahaemolyticus, and Pseudomonas aeruginosa), and one fungus (Candida albicans). The extracts exhibited both antibacterial and antifungal activities against tested microorganisms. Ethanolic roselle extract showed significant antibacterial activity (P < 0.05) against all tested bacterial strains, while no inhibitory effect on Candida albicans (CA) was observed. Only the ethanolic extracts of clove and thyme showed antifungal effects against CA with inhibition zones ranging from 25.2 ± 1.4 to 15.8 ± 1.2 mm, respectively. Bacillus cereus (BC) appears to be the most sensitive strain to the aqueous extract of clove with a MIC of 0.315%. To enhance our understanding of antimicrobial activity mechanism of plant extracts, the changes in internal pH (pHint), and membrane potential were measured in Staphylococcus aureus (SA) and Escherichia coli (EC) cells after exposure to the plant extracts. The results indicated that the plant extracts significantly affected the cell membrane of Gram-positive and Gram-negative bacteria, as demonstrated by the decline in pHint as well as cell membrane hyperpolarization. In conclusion, plant extracts are of great value as natural antimicrobials and can use safely as food preservatives
Application of Web 2.0 Tools in Delivering Library Services: A Case of Selected Libraries in Tanzania
(2012) Muneja, Paul S.; Abungu, Apollo K.; Makori, E. O.
This paper explores the adoption and application of Web 2.0 tools in delivering library services in selected libraries in Tanzania. The paper investigates the ways in which librarians are adopting the tools to enhance services. The study examines Web 2.0 tools used by libraries in delivering their services, factors influencing the use of Web2.0 tools, challenges and prospects in their usage. The findings reveal that librarians in Tanzania have started using various Web 2.0 tools in varying degrees and the most common tool is Facebook. The findings also reveal that most librarians are motivated to use these tools because they are free and open source and relatively easy to apply. Sharing resources, communication and promotion of services were the main reasons why this tools are used. Challenges include unreliable power and internet access. Advantades included, increase in resources awareness, better communication and interest in library usage. Recommendations suggest that institutions should develop policies that adopt the use of emerging technologies and alternatives to reliable power sources such as solar and generators.
Aquaculture and Fisheries Extension. In: Mgaya, Y.D. and Mahongo, S.B. (Editors), Lake Victoria Fisheries Resources: Research and Management in Tanzania.
(Springer, 2017-11-29) Shoko, A.P.; Mgaya, Y.D.; Samwel Mchele Limbu; Hoza, R.
The dwindling catch from Lake Victoria has caused an insufficient fish supply to the population of the Lake Victoria basin, Tanzania. The decrease in catch rates and demand for fish has created room for fish farming practices at both small and commercial scales in the Lake Basin. This chapter provides a result-oriented status of aquaculture research and development efforts made by the government and Non-Governmental Organizations (NGOs) in the Lake Basin from the colonial era to the present. The chapter also highlights strengths, weaknesses, opportunities and challenges (SWOCs) to aquaculture development in the basin. Results show that the basin has a high potential for fish farming development due to suitable characteristics for fish farming. Fishponds are the common culture system used in fish farming in the basin. The ponds are stocked with either Nile tilapia Oreochromis niloticus or African sharptooth catfish, Clarias gariepinus, reared in monoculture or polyculture. A system of integrated aquaculture-agriculture (IAA) farming is also practised in some areas of the basin. The yield from the lake basin has increased with time due to improved pond management techniques. However, more room is available for further increase pending the adoption of technology and improved extension services. Fish farming could help to reduce fishing pressure on capture fisheries in the main lake and contribute significantly to the conservation of the lake’s biodiversity. Ultimately, fish farming will generate income for the people, which is in line with the government’s efforts to alleviate poverty in the country.
Aquaculture Research and Development as an Entry-Point and Contributor to Natural Resources and Coastal Management
(Taylor & Francis, 2010-05) Haws, Maria; Crawford, Brian; Portella, Maria Célia; Ellis, Simon; Jiddawi, Narriman Saleh; Mmochi, Aviti J.; Gaxiola-Camacho, Eladio; Dominguez, Guillermo Rodriguez; Rodriguez, Gustavo; Francis, Julius; Leclair, Carlos Rivas; Coze, Agnes Saborio
Recent, fervent international dialogue concerning the existence and magnitude of impacts associated with aquaculture has had both positive and negative outcomes. Aquaculture stakeholders have become sensitized to requirements for improved environmental management of aquaculture. On the other hand, in some cases aquaculture development has been negatively affected by some of the unwarranted and unproved allegations to the detriment of the stakeholders most in need of aquaculture development (i.e., resource users, particularly the poor, who are dependent on natural resources). These resource users are targeted by, and directly influence biodiversity and conservation agendas; hence the need to understand how to gain their active participation. This discussion focuses on examples of how aquaculture research and development can be a useful tool or strategy for resource management initiatives and provide tangible positive including increased stakeholder participation and cooperation, offering alternatives to resource extraction and use in otherwise difficult or intransigent resource management conflicts.
AquaEco 40 (2006) Decomposition of Zizania latifolia AGB and BGB
(2013-04) Sanderson, Brian; Shilla, Daniel; Fujino, Takeshi; Asaeda, Takashi
Decomposition of aboveground and belowground organs of the emergent macrophyte Z.latifolia wasinvestigated using a litterbag technique for a period of 359 days in a freshwater marsh in Japan. Above-ground parts were classified into: leaves, sheaths and stems. Belowground parts were classified into: hor-izontal rhizomes (new rhizome, hard rhizome, soft rhizome) and vertical rhizome (stembase). The decayrate (k) was 0.0036 day)1, 0.0033 day)1and 0.0021 day)1for leaves, sheaths and stems, respectively. Forbelowground parts, the decay rate varied considerably from 0.0018 day)1to 0.0079 day)1, according todifferences in the initial chemical compositions of rhizomes. After 359 days of decay, new rhizomes lost94% of their original dry mass, compared with a loss of 48 –84% for the other rhizomes. There was asignificant positive relationshi p between litter quality and decay rate for horizontal rhizomes. For the newrhizomes, which had an internal nitrogen content of 24.2 mg N g)1dry mass, the mass loss was 40% higherthan that of soft rhizomes, which had an internal N content of 9.8 mg N g)1dry mass. Over the period of359 days, the nitrogen concentration in all rhizome types decreased to levels lower than initial values, butthe phosphorus concentration remained constant after an initial leaching loss. Most nitrogen and phos-phorus were lost during the first 45 days of decay. Changes in carbon to nitrogen (C:N) and carbon tophosphorus (C:P) ratios basically followed inversed trends of the nitrogen and phosphorus concentrations.
Aquatic Ecosystem Services and Management in East Africa: The Tanzania Case
(Springer Netherlands, 2015-08) Kaaya, Lulu Tunu; Lugomela, George V.
Diverse aquatic ecosystems in Tanzania provide economically important ecosystem services. The rich supply of these services is under threat. Projections show critical water scarcity in the country by the year 2050. Demography, excessive withdrawals, land use changes, exotic species invasions and climate change that result in loss of perennial flows, eutrophication, sedimentation, and algal blooms are among the major drivers of aquatic ecosystem changes in Tanzania. Water resources uses and their management in Tanzania are mainly determined by the national macroeconomics and policies. In this review, Great Ruaha River (GRR) and Lake Victoria Basin (LVB) are used as case examples for demonstrating status, trends and drivers of ecosystem changes, and their management options in Tanzania through government and donor efforts. As a way forward, in the new Tanzania National Water Policy (NAWAPO) of 2002, Integrated Water Resource Management (IWRM) approaches as tools to ensure ecosystem protection and stakeholder’s participation have been adopted. Water for environment is given a second priority in water allocation after basic human needs. The Integrated Water Resources management and Development (IWRMD) plans currently being developed will form legal basis in management of water in an environmentally and ecosystem responsible manner. Through the IWRMD approved plans, drastic actions can be legally taken to protect and/or restore important ecosystem services in hotspot areas like the GRR.
Are Fiddler Crabs Potentially Useful Ecosystem Engineers in Mangrove Wastewater Wetlands? Mari Poll Bull
(Elsevier, 2009) Penha-Lopes, Gil P.; Bartolini, Fabrizio; Samwel Mchele Limbu; Cannicci, Stefano; Kristensen, Erik; Paula, José
The effect of different organic-rich sewage concentration (0%, 20% and 60% diluted in seawater) and absence or presence of mangrove trees on the survival, bioturbation activities and burrow morphology of fiddler crabs species was assessed. After 6 months, males of both species always showed higher survival (80%) when compared to females (20%). Crabs inhabiting pristine conditions achieved higher survival (67–87%) than those living in sewage-exposed mesocosms (40–71%). At 60% sewage loading, fiddler crabs processed less sediment (34–46%) during feeding and excavated slightly more sediment (45– 80%) than at pristine conditions. While percent volume of the burrow chambers increased (13–66%) at contaminated mesocosms for both vegetation conditions, burrows were shallower (33%) in bare cells loaded with sewage. The results show that fiddler crabs presented moderate mortality levels in these artificial mangrove wetlands, but mainly in sewage impacted cells. However, they still function as ecosystem engineers through bioturbation activities and burrow construction.
Aspilia mossambicensis and Azadirachta indica medicinal leaf powders modulate physiological parameters of Nile tilapia (Oreochromis niloticus).
(Taylor & Francis, 2018-05-03) Imani Benedict, Kapinga; Samwel Mchele Limbu; Nazael Amos, Madalla; Wahabu Hamisi, Kimaro; Rashid Adam, Tamahtamah
Growing mixed-sex Nile tilapia, Oreochromis niloticus in earthen ponds to table size is a major challenge due to its early maturity and prolific breeding. This study determined the effects of two medicinal plants; Aspilia plant, Aspilia mossambicensis and Neem tree, Azadirachta indica on hatchlings production, growth performance, feed utilization, survival and haematology of O. niloticus. Experimental diets were prepared by adding 1.0, 2.0, 4.0 and 8.0 g of either A. mossambicensis or A. indica leaf powders into a kg of the control diet subsequently administered daily to twenty triplicates of O. niloticus for three months. Both A. mossambicensis and A. indica leaf powder at the used doses, reduced significantly hatchlings production of O. niloticus when compared to the control (P < .05). The lowest value of hatchlings count was found in A. indica dose 8.0 g kg−1 (P < .05). The use of A. mossambicensis leaf powder at a dose of 4.0 g kg−1 improved significantly growth performance and feed utilization (P < .05). In contrast, survival rate was not affected significantly by the two plants (P > .05). Both plants differentially increased significantly haematological parameters such as Hb concentration, packed cell volume (PCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), white blood cells (WBC), monocyte and lymphocytes while reduced significantly neutrophils and eosinophils (P < .05). In conclusion, A. mossambicensis and A. indica leaf powders control prolific breeding of O. niloticus, modulate its growth performance and feed utilization. The two plants also modulate haematological parameters of O. niloticus indicating immunological response towards stress or intoxication, however, the values obtained were not beyond the recommended range for healthy fish.
Assessing Poverty in Small Scale Fisheries in Lake Victoria, Kenya
(Blackwell Publishing Ltd, 2010) Onyango, Paul O.; Jentoft, Svein
Poverty is a pervasive issue in small-scale fisheries. Not only does it affect a substantial population, it is also a complex problem that is difficult to define, explain and solve. Thus, poverty in small-scale fisheries constitutes what in the planning literature is sometimes identified as a ‘wicked problem’. This paper applies the interactive governance framework to identify the limits of, and conditions for, governability and how they affect poverty, using the Lake Victoria small-scale fisheries in Tanzania as an illustrative case. More specifically, the paper first uses the three systems model of the interactive governance framework, i.e., the system-tobe-governed, the governing system, and the governing interaction, to explore poverty as a ‘wicked problem’ involving challenges pertaining to governability. Secondly, the paper suggests ‘governance elements’ that are fundamental for addressing poverty through the first, second, and third orders of governance. The paper emphasizes the importance of social values as crucial entry points in addressing poverty in smallscale fisheries.
Assessment of Antioxidant Properties of Honeys from Tanzania
(www.iiste.org, 2014) Muruke, Masoud H.
In this study, levels and properties of antioxidants, antiradical and iron chelating activities of honeybee and stingless bee honeys were determined using standard methods. The relationship between honey colour and the studied antioxidants was also explored. Phenolic content of stingless bees honey samples (mean value 847.6 mgGAE/100g) was significantly higher (P<0.0001) than that of raw (412.6 mgGAE/100g) and processed (218.4 mgGAE/100g) honeybee honey samples, respectively. Mean value of flavonoid content was 84.96 mgRE/100g for stingless bee honeys, 44.82 mgRE/100g for processed honeybee honeys and 41.60 mgRE/100g for raw honeybee honeys. β-Carotene and lycopene content varied among the three honey categories studied. Honey from stingless bees exhibited higher levels of the two antioxidants than honey bee honeys. Vitamin C content ranged from 20.4 – 66.7 mg/100g in processed honey, 42.5 – 61.6 mg/100g in raw honeybees honey and from 56.2 – 67.6 mg/100g in stingless bee honeys. The number of antiradical activity units in 1 mg of honey (EAU515) varied significantly between the honey categories (P<0.0001). The mean values were 5.21 mg/100g for processed honeybee honeys, 6.8 mg/100g for raw honeybee honeys and 10.6 mg/100g for stingless bee honeys. DPPH radical scavenging and iron chelating activities were highest (lowest EC50) in stingless bee honeys compared to honeybee honeys. EC50 mean value for DPPH was lowest (4.19 mg/ml) in stingless bee honeys, 12.93 mg/ml for raw honeybees honey and 18.03 for processed honeybees’ honey. Similarly, iron chelating activity was highest in stingless bee honeys (EC50 0.04 mg/ml) followed by raw honeybee honeys (EC50 0.057 mg/ml) and processes honeybee honeys (EC50 0.158). A diversity of honey colours ranging from light coloured to dark honeys was recorded in the samples studied. Majority of honeybee honey colours were described as white and light amber, while all the stingless bee honeys were between light amber and amber colours. There were strong positive correlations among the antioxidants studied (r ≥ 0.5 at P<0.01). Honey colour intensity was found to correlate positively with all antioxidants studied. Consistently darker honeys were found to contain higher levels of antioxidants than lighter honeys. In overall, Tanzanian honeys studied contains high levels of antioxidants, depicting good quality characteristics for use as food and as medicine.
Assessment of Faecal Bacteria Contamination in Selected Coastal Waters of Tanzania
(Macrothink Institute, 2013) Lazaro, Samson; Mwakalobo, Samson; Thomas, Jacob; Lyimo, Thomas J.; Lugomela, Charles
Coastal communities of Tanzania use natural water systems such as rivers, estuaries and 64 marine for various activities like drinking, fishing, washing and bathing. However, there is scanty information on the safety for these water bodies for the various uses. In this study faecal indicator bacteria were assessed in three sites along the coast of Tanzania (i.e. Pangani Estuary in Tanga Region, Ruvu Estuary in Pwani Region and Mzinga Creek in Dar Es Salaam Region). At each site, three sampling stations covering fresh, brackish and marine waters were selected for monthly sampling between July 2009 and June 2010. Faecal bacterial indicators were generally higher in Mzinga Creek compared to the rest of the study sites with significant differences between Mzinga Creek and Pangani Estuary for total coliforms (TC) and faecal coliforms (FC) (P < 0.05). All faecal indicator bacteria were significantly higher in fresh waters compared to brackish and marine waters (P = 0.0001), for TC and FC and P = 0.001 for Enterococcus (ENT). The faecal indicator bacteria correlated positive to each other and negatively to some environmental parameters namely pH and Salinity. Results suggest allochthonous sources of contamination and the influence of environmental factors. Generally the faecal bacterial indicators in the studied waters along the coast of Tanzania were within the acceptable standards according to WHO and USEPA indicating low risks situation for recreational purposes. However, these levels of faecal bacteria does not warrant the use in the studied estuaries for shellfish harvesting and the fresh water is not suitable for direct drinking. Further studies and monitoring programs are recommended to substantiate the current results.
Assessment of Heavy Metal Pollution in Sediment and Polychaete Worms from the Mzinga Creek and Ras Dege Mangrove Ecosystems, Dar es Salaam, Tanzania
(University of Dar Es Salaam, 2008) Mtanga, A.; Machiwa, John F.
Metal pollution in the Mzinga creek mangrove stand was assessed and compared with a relatively pristine mangrove forest at Ras Dege in Dar es Salaam. The concentrations of cadmium, chromium, copper, lead and zinc in sediment and polychaete worms (Capitella sp.) were analyzed by ICP-AES and mercury was analyzed by a semi-automatic analyzer. Concentrations of most of the metals analyzed were higher in samples from Mzinga creek than from Ras Dege. Sediment samples from the Mzinga creek were enriched with Cu (EF = 7.4), Hg (EF = 5.3) and Cr (EF = 3.3) relative to sediment samples from Ras Dege, which were mostly at natural background levels. Polychaete worm samples from the Mzinga creek also accumulated high amounts of metals when compared to samples from Ras Dege. The data show perturbation of the Mzinga creek from human activities in the catchment.
Assessment of Quality of Tanzanian Honey based on Physicochemical Properties
(www.iiste.org, 2014) Muruke, Masoud H.
Quality of Tanzanian honey based on physicochemical parameters namely water content, sugar content, pH, ash content, hydroxymethyl furfural (HMF) and honey colour was studied using 26 honey samples collected from ten popular honey producing regions. Analyses were carried out in triplicates using standard methods. Data was analysed using averages, correlation and ANOVA tests. Majority of the honeybees’ honey samples were light coloured while all stingless bees honey samples were dark coloured. Dark coloured honeys contained more minerals; mainly iron, copper and manganese which make them especially fit for medicinal purposes. pH values ranged from 2.61±0.12 to 4.37±0.08, stingless bees honey samples were more acidic than honeybees’ honey samples. Total sugar content values (64.16-84.84 g/100g) were all above the minimum requirement of the national and international standards of not less than 60g/100g. HMF values ranged from 5.0 – 26.4 mg/kg honey, an indication of good quality, being far below the maximum limit allowed by national and international standards of 40mg/kg or 80mg/kg for honeys from the tropics. Of the 26 honey samples studied, all 5 honey samples from stingless bees and 3 from honeybees had moisture content levels above 21%, the maximum limit allowed by national and international standards.. With the exception of two samples from stingless bees, all honeybees honey samples met the minimum requirements of national and international quality standards of maximum allowable ash content of 0.6 %. ANOVA results showed significant differences in the studied physicochemical parameters between groups of honey samples, namely processed honey raw honey and stingless bees’ honey at P<0.05. Pearson correlation analysis showed strong correlation coefficients at P<0.05 between some parameters studied. In conclusion honey colour and moisture content are two important physicochemical parameters that may be used to assess quality of honey.
The Atmospheric Deposition of Phosphorus in Lake Victoria (East Africa)
(Springer Link, 2005) Tamatamah, Rashid A.; Hecky, Robert E.; Duthie, H. C.
Wet and dry atmospheric fluxes of total phosphorus (TP) and soluble reactive phosphorus (SRP) measured at four sites over a 12-month period were used to estimate lake-wide atmospheric phosphorus (P) deposition to Lake Victoria, East Africa. Atmospheric samples were collected in plastic buckets with top diameter of 25.5 cm by 30 cm deep. The highest P loading rates of 2.7 (TP) and 0.8 (SRP) kg ha 2 year 1 were measured at Mwanza compared to less than 1.9 (TP) and 0.65 (SRP) kg ha 2 year 1 measured in other three sites. By applying these loading rates to the lake surface, it was estimated that 13.5 ktons (13.5 · 103 kg) of TP were deposited annually into the lake from the atmosphere. Thirty-two percent of the total was found to be in the SRP form. Dryfall, a component ignored in previous studies exceeded wet deposition by contributing 75% of the total P input. However, materials deposited by dryfall made a lesser contribution to soluble form of phosphorus, as SRP concentrations in the wet samples were 2–3 times higher than SRP concentrations in dry samples. The annual fluxes of phosphorus measured on the south and western shores of Lake Victoria (1.8–2.7 kg ha 2 year 1 ) are near the upper range of similar fluxes measured in the tropics. In comparison with the existing estimates of municipal and runoff P inputs from other studies, it is estimated that atmospheric deposition represent 55% of the total phosphorus input to the Lake Victoria. The four sampling sites were fairly clustered and wet and dry P deposition data were collected from shore/land stations and applied to open lake areas to estimate lake-wide P deposition. In this regard, the estimates determined here should be viewed as a first order approximation of actual P load deposited into the lake.
Autecology of the Toxic Dinoflagellate Gambierdiscus toxicus Adachi et Fukyo (Dinophyceae) in Central Coastal Areas of Tanzania
(2006) Lugomela, Charles

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