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Petrography And Mineral Chemistry Of The Pelitic And Semi-Pelitic Gneisses Of The Merelani Tanzanite Mining Area, Northeastern Tanzania, E. P. Malisa
Tanzania Journal of Science
Sillimanite/kyanite + K-feldspar + quartz ± garnet + biotite ± Fe-Ti oxide-bearing rocks occur associated with calc-silicate rocks in the Merelani tanzanite mining area north-eastern Tanzania. The whole rock chemistry shows varying rock oxidation ratios, which are reflected in the mineralogical assemblages. Almandine garnet is oxidized to mixtures of hematite, quartz, and hydrous aluminosilicates in oxidized rocks and is absent in highly oxidized rocks. In the latter, ilmenite is oxidized into mixtures of rutile and hematite. Such relatively high temperature alteration/oxidation effects could have occurred with the influx of water. Absence of staurolite in these aluminium-rich rocks is indicative of …
Performance Of A Sisal Fibre Fixed-Bed Anaerobic Digester For Biogas Production From Sisal Pulp Waste, A. Mshandete, A. K. Kivaisi, M. S. T. Rubindamayugi, L. Björnsson, B. Mattiasson
Performance Of A Sisal Fibre Fixed-Bed Anaerobic Digester For Biogas Production From Sisal Pulp Waste, A. Mshandete, A. K. Kivaisi, M. S. T. Rubindamayugi, L. Björnsson, B. Mattiasson
Tanzania Journal of Science
A single stage anaerobic digester employing a sisal fibre waste fixed bed was studied for biogas production from sisal pulp waste. The fibre was colonized by microorganisms involved in biogas production. The sisal pulp waste to be digested was fed from the top and was sprinkled intermittently with recirculating leachate from the material. Organic loading rates of 0.1-10 kg volatile solids (VS) m-3d-1 could be applied and methane yields in the range of 0.13-0.48 m3 CH4 kg-1 VS added were obtained. The average methane content in the biogas produced from sisal pulp waste was 55%, and the biogas production rate …
The Influence Of Quantization Process On The Performance Of Global Entropic Thresholding Algorithms Using Electrical Capacitance Tomography Data, A. J. Mwambela
The Influence Of Quantization Process On The Performance Of Global Entropic Thresholding Algorithms Using Electrical Capacitance Tomography Data, A. J. Mwambela
Tanzania Journal of Science
In measuring component fraction in multiphase flows using tomographic techniques, it is desirable to use a high speed tomography system capable of generating 100 tomograms per second. The electrical capacitance tomography system in this regard is considered to be the best among the available tomographic techniques. However, due to its inherent limitations the system generates distorted reconstructed tomograms necessitating the use of extra signal processing techniques such as thresholding to minimize these distortions. Whilst thresholding technique has been effective in minimizing distortions, the additional computation associated with the process limits the speed of tomogram generation desired from the system. Further, …
Environmental Risks For Gemstone Miners With Reference To Merelani Tanzanite Mining Area, Northeastern Tanzania, Ep Malisa, Cp Kinabo
Environmental Risks For Gemstone Miners With Reference To Merelani Tanzanite Mining Area, Northeastern Tanzania, Ep Malisa, Cp Kinabo
Tanzania Journal of Science
Artisanal and small-scale gemstone miners are the workers with the highest health risk exposure in Tanzania. Gemstone mining at Merelani tanzanite mines which has gone to depths of 100 m or more in narrow straight and inclined shafts, underground artisanal miners work under a very harsh environment. Tanzanite deposits are located within sheared zones, lying along a deep-seated Lelatema fault zones. Rocks along these zones which are mainly graphitic and or/gypsum-bearing gneisses surrounded by limestone are soft, fractured and strongly weathered. Poor mining techniques, lack of geological background, chronic shortage of capital, and the lack of awareness on environmental pollution …
Influence Of Simultaneous Infestations Of Prostephanus Truncatus And Sitophilus Zeamaison The Reproductive Performance And Maize Damage, C P Rugumamu
Tanzania Journal of Science
This study examined the combined effect of Prostephanus truncatus and Sitophilus zeamais infestations on their reproductive performance and on the damage they cause to maize variety ZM 621 with 12.5% moisture content. The specific objective was to determine the number of the insect pests at F1 and F2 and the grain weight losses caused by the simultaneous pests\' infestations of shelled maize in the search for a control strategy. The results showed a change in adult insect numbers from F1 to F2. During single infestation the change in P. truncatus was 47.54% while in simultaneous infestations it was 41.66%. The …
Recent Trends In Accumulation Rate, Elemental And Isotopic Composition Of Organic Matter In The Magu Bay, Lake Victoria, Ann Muzuka, Jf Machiwa, C Lugomela
Recent Trends In Accumulation Rate, Elemental And Isotopic Composition Of Organic Matter In The Magu Bay, Lake Victoria, Ann Muzuka, Jf Machiwa, C Lugomela
Tanzania Journal of Science
Stable isotope composition of organic carbon (OC), 14C data, OC and nitrogen content of recently deposited sediments in Magu Bay of Speke Gulf, Lake Victoria are used to document accumulation rates, sources and distribution of organic matter in the bay. The stable isotope values of both organic carbon and nitrogen decrease towards offshore, and this trend is associated with increase in the contents of organic carbon and nitrogen. The isotope results show that the organic material deposited in the bay are generally derived from C4 type of plants and are not transported far from the river mouth. Also the results …
Fish Species And Size Distribution And Abundance In Different Areas In Lake Victoria, Tanzania, A I Chande, H A Mhitu
Fish Species And Size Distribution And Abundance In Different Areas In Lake Victoria, Tanzania, A I Chande, H A Mhitu
Tanzania Journal of Science
The study was carried out to investigate fish species distribution and abundance in different areas and size structure variations according to depth in Lake Victoria, Tanzania. Data were collected using a bottom trawl net during rainy and dry seasons in 2002. The results show that there were significant differences in catch rates between rainy and dry seasons (F (12, 12) = 2.69; p < 0.05). The rainy season recorded higher catch rates (36.25 - 106.61 kg/hr) than during the dry season (14.30 - 67.90 kg/hr). The haplochromines catch rates were higher during the dry season (11.08 kg/hr) than during the rainy season (7.72 kg/hr), however, the differences were not significant (c2 = 0.60, df = 1, p > 0.05). The distribution of the fish species in different areas recorded a significant difference during the dry season (Q = 18.254, df = 8, P < 0.001), while during the rainy season the difference was not significant (Q = 10.667, df = 8, P > 0.001). Moreover, the results show that small individuals dominated in shallow waters …
Micron-Sized Polymeric Particles From Cashew Nut Shell Liquid: Influence Of Reaction Parameters On Particle Size, Ymm Makame, W Johnson, Ll Mkayula
Micron-Sized Polymeric Particles From Cashew Nut Shell Liquid: Influence Of Reaction Parameters On Particle Size, Ymm Makame, W Johnson, Ll Mkayula
Tanzania Journal of Science
Cashew nut shell liquid based polymer latexes of narrow size distribution and average particle sizes ranging from 0.1 to 0.4 µm were prepared by base catalysed emulsion polycondensation of cashew nut shell liquid of 820 centipoises viscosity with formaldehyde. The influence of emulsifier concentration, sodium hydroxide concentration and stirring rate on average particle size and size distribution was studied for the given geometry of the reactor and the stirrer. It was found that these variables have a significant effect on the particle size and particle size distribution and that average particles size can be predicted and controlled by the choice …
Distribution And Abundance Of The Edible Orchids Of The Southern Highlands Of Tanzania, Ams Nyomora
Distribution And Abundance Of The Edible Orchids Of The Southern Highlands Of Tanzania, Ams Nyomora
Tanzania Journal of Science
All orchids have showy flowers and many are therefore popular as exotic houseplants as well as contributing significantly to eco-tourism. A special attribute of some orchid genera is the production of edible tubers, an attribute that can contradict eco-tourism if harvesting is not done sustainably. Such is the case in the Southern Highlands where for example, Kitulo Plateau has been gazetted to be a National Park but where edible orchid harvesting is a serious conservation problem. Botanically, unsustainable harvesting can mean the loss of important germplasm even before some species are known to exist. A field survey was undertaken for …
Pesticide Residues In Water From Tpc Sugarcane Plantations And Environs, Kilimanjaro Region, Tanzania, H Hellar, Ma Kishimba
Pesticide Residues In Water From Tpc Sugarcane Plantations And Environs, Kilimanjaro Region, Tanzania, H Hellar, Ma Kishimba
Tanzania Journal of Science
We report herein, the analysis of water samples collected from TPC Sugarcane Plantation and its environs in Kilimanjaro region, which is the earliest intensive user of pesticides in Tanzania. A total of 50 water samples collected from 18 sampling sites between 2000 and 2001 were analyzed for pesticide residues. The organochlorines aldrin, dieldrin, heptachlor epoxide, HCHs, endosulfans and DDTs were detected with mean concentrations ranging from 1.1 to 636.7 ng/l. DDT and its metabolites were the most dominant in the detected residues whereas the endosulfans were the least dominant The residues\' concentrations were higher in the sugarcane fields than in …
Comparative Analysis Of Mercury Content In Human Hair And Cosmetic Products Used In Dar Es Salaam, Tanzania, C P Kinabo
Comparative Analysis Of Mercury Content In Human Hair And Cosmetic Products Used In Dar Es Salaam, Tanzania, C P Kinabo
Tanzania Journal of Science
Total mercury (T-Hg) concentrations were analysed in human hairs and cosmetic products sold in Dar es Salaam Tanzania. The average total mercury (T-Hg) concentrations in the scalp hair of females using mercury based cosmetic creams and soaps ranged from 7.0 ± 0.4 to 880 ± 12 ppm. Highest T-Hg concentrations were found in females who work in beauty hair salons and the lowest concentrations were found among students. The average values in non-cosmetic users were found to be lower, with mercury ranging from 0.57 ± 0.07 to 8.29 ± 1.22 ppm. Analysis of cosmetic products indicated high values, ranging from …
Levels Of Nitrate And Phosphate In Some Satellite Lakes Within The Lake Victoria Basin, Tanzania, Jj Kulekana
Levels Of Nitrate And Phosphate In Some Satellite Lakes Within The Lake Victoria Basin, Tanzania, Jj Kulekana
Tanzania Journal of Science
Levels of nitrates (NO3-N) and phosphates (PO4-P) in some satellite lakes within the Lake Victoria basin were determined in Kagera (Lake Burigi), in Mara (River Mara) and in Mwanza region (Lake Malimbe) during August/September 2002 (dry season) and January/February 2003 (wet season). Water samples were collected using a van Dorn water sampler at chosen points from both deep and shallow areas of the water bodies. Results of the two surveys revealed that deep and shallow areas of the lakes had varying nutrient levels. In deep waters, PO4-P values ranged between 0.171-0.225mg/l, 0.067-0.364mg/l, and 0.043-0.096 mg/l in Lake Malimbe, Burigi and …
Zooplankton Communities Of Selected Stations Of Lake Victoria, Rk Waya, Ja Mwambungu
Zooplankton Communities Of Selected Stations Of Lake Victoria, Rk Waya, Ja Mwambungu
Tanzania Journal of Science
Species composition and diversity of zooplankton communities of Lake Victoria (Tanzanian waters) were studied. In the shallow waters zooplankton were collected between March and April, and between August and December 2000. In deeper waters zooplankton were collected in August 2001. Overall, 20 genera and 29 species of zooplankton were observed in the shallow waters whereas 12 genera and 20 species of zooplankton were encountered in the deeper waters. The highest abundance was recorded in the deeper waters (2,481,633-2). In the shallow waters the cyclopoid copepods dominated the zooplankton community, the common species being Thermocyclops emini and Thermocyclops neglectus. In the …
The Diversity Of Benthic Mollusks Of Lake Victoria And Lake Burigi, Ja Mwambungu
The Diversity Of Benthic Mollusks Of Lake Victoria And Lake Burigi, Ja Mwambungu
Tanzania Journal of Science
Molluscan diversity, abundance and distribution in sediments of Lake Victoria and its satellite lake, Lake Burigi, were investigated. The survey was carried out in January and February 2002 for Lake Victoria and in March and April 2002 for Lake Burigi. Ten genera were recorded from four zones of Lake Victoria while only three genera were recorded from Lake Burigi. In Lake Victoria the most diverse zone was Mara zone. The mollusca communities comprised of Bellamya, Gabbiella, Melanoides, Bulinus, Biomphalaria and Cleopatra (Gastropoda) and Corbicula, Eupera (Byssanodonta), Caelatura and Sphaerium (Bivalvia). Lake Burigi comprised of Melanoides, Bulinus and Biomphalaria. Melanoides tuberculata …
Phytoplankton And Nutrients Studies In Magu Bay, Speke Gulf, Lake Victoria, (Tanzania) Following The 2001 Principal Rain Season, Jf Machiwa, C Lugomela, Ann Muzuka
Phytoplankton And Nutrients Studies In Magu Bay, Speke Gulf, Lake Victoria, (Tanzania) Following The 2001 Principal Rain Season, Jf Machiwa, C Lugomela, Ann Muzuka
Tanzania Journal of Science
Phytoplankton abundance and species composition in relation to some physico-chemical parameters were studied in Magu Bay, Lake Victoria, in May 2001. Investigations on the influence of Simiyu River on the biological and physical characteristics of the Bay were carried out. Surface and bottom currents flowed in the northeast direction close to the river mouth but were completely reversed after about 1.5 km from the river mouth. Most suspended particles brought in by the river were deposited within 0.5 km after entering the lake. Nutrient concentrations were generally high towards the eastern part of the bay as compared to the rest …
Species Composition And Biomass Estimates Of Zooplankton In Some Water Bodies Within Lake Victoria Basin, Rk Waya, Ai Chande
Species Composition And Biomass Estimates Of Zooplankton In Some Water Bodies Within Lake Victoria Basin, Rk Waya, Ai Chande
Tanzania Journal of Science
Zooplankton communities were identified and their abundance and biomass estimated in some selected satellite lakes and Mara River in Lake Victoria basin, during wet and dry seasons in 2002. Samples were collected from eight water bodies. Three stations were sampled from each water body using a plankton net (40 µm mesh size) hauled vertically through the water column. The zooplankton community comprised mainly crustacea and rotifers. The results show that the number of species collected during the wet and dry seasons was 31 species and 28 species, respectively. The Shannon wiener diversity indices were not significantly different (Mann-Whitney U Test …
Spatial Distribution Of Parasites Along The Gut Of The Catfish Clarias Gariepinus (Burchell, 1822) (Clariidae) From The Mwanza Gulf, Lake Victoria, G Nkwengulila, C Mwita
Spatial Distribution Of Parasites Along The Gut Of The Catfish Clarias Gariepinus (Burchell, 1822) (Clariidae) From The Mwanza Gulf, Lake Victoria, G Nkwengulila, C Mwita
Tanzania Journal of Science
The diversity, abundance and spatial distribution of parasites in the alimentary tract of Clarias gariepinus from the Mwanza Gulf were investigated. Ten parasite species were recovered; the Trematoda, Cestoda and Nematoda were each represented by three species while Dolops ranarum was the only crustacean recovered from the posterior part of the buccal cavity. Parasites diversity was highest in the small intestine and the stomach. Although the gut community of C. gariepinus studied was rich in intensity and individual numbers of helminth species, helminth infection in most sections of the gut comprised of monospecific infection and thus cohabiting interspecific interaction was …
Phytoplankton Species Diversity And Abundance In Satellite Lakes Of Lake Victoria Basin (Tanzanian Side), Bc Sekadende, Ase Mbonde, S Shayo, Tj Lyimo
Phytoplankton Species Diversity And Abundance In Satellite Lakes Of Lake Victoria Basin (Tanzanian Side), Bc Sekadende, Ase Mbonde, S Shayo, Tj Lyimo
Tanzania Journal of Science
Studies on phytoplankton species diversity and abundance were carried out in 8 selected satellite lakes within the Lake Victoria basin during two wet seasons (March-April 2002 and January-February 2003) and one dry season (August-September 2002). Higher species richness (76 species) of phytoplankton species was recorded in rain season than in dry season (47 species). The observed species represents six classes, cyanophytes, chlorophytes, cryptophytes, basillariophytes, euglenophytes and dinophytes, of fresh water algal flora. Species diversity was generally low, with diversity indices (H\') ranging from 0.21 for Lake Kyarano to 0.09 for Lake Ikimba. On the contrary, Lake Katwe was richer in …
Diurnal Feeding Patterns And Food Habits Of Lates Niloticus In The Speke Gulf, Lake Victoria, Ha Mhitu, Ai Chande
Diurnal Feeding Patterns And Food Habits Of Lates Niloticus In The Speke Gulf, Lake Victoria, Ha Mhitu, Ai Chande
Tanzania Journal of Science
Twenty four hour sampling sessions were conducted to investigate the feeding patterns and food habits of Lates niloticus in the Speke Gulf, Lake Victoria during January/February, July/August and December 2002. Feeding activity was more pronounced during daytime mostly in morning hours than during the night. The most dominant food item was haplochromines. There was a significant difference in the occurrence of food items in the gut of L. niloticus with time. However, there was no significant difference in the occurrence of food items in the habitat at different times. The study concludes with a recommendation for fishermen to set their …
Relationship Between Water Transparency And Species Richness Of Surviving Haplochromines In Selected Habitats In Mwanza Gulf - Lake Victoria, Hdj Mrosso, Bs Msuku, O Seehausen
Relationship Between Water Transparency And Species Richness Of Surviving Haplochromines In Selected Habitats In Mwanza Gulf - Lake Victoria, Hdj Mrosso, Bs Msuku, O Seehausen
Tanzania Journal of Science
Several of the surviving haplochromine species have been recorded in habitats of different water transparencies within the Mwanza Gulf. Sampling for the haplochromines was carried out in muddy, rocky, sandy and vegetated habitats. All of the recorded species had been reported previously. Fewer species were encountered than previously reported in the same sampling stations. There was evidence for positive correlation between species richness and water transparency that was reinforced with data on ecological differentiation. Further exploration and conservation measures of diversity have been suggested for Lake Victoria haplochromines.
Fish Species Composition, Size Structure And Distribution In Non-Trawlable Areas Of Lake Victoria (Tanzania) With Emphasis On Mwanza Gulf And Mori Bay, Jdr Bayona, B Msuku, S Mzighani
Fish Species Composition, Size Structure And Distribution In Non-Trawlable Areas Of Lake Victoria (Tanzania) With Emphasis On Mwanza Gulf And Mori Bay, Jdr Bayona, B Msuku, S Mzighani
Tanzania Journal of Science
Fish diversity studies in littoral non-trawlable areas of Lake Victoria (Tanzania) were undertaken during six systematic surveys (November 2000 to December 2002). Information on fish species composition, size structure as well as spatial and temporal distribution was generated from gill-netting, beach-seining and electric fishing. Lates niloticus, indicated a declining trend in composition from 78.9% in March 2001 to 5.1% in July 2002. The species, however, increased to 40.6 % in catch composition as of December 2002, exhibiting somewhat inverse trends in distribution with Oreochromis niloticus and haplochromines in the lake fisheries. The surveys identified over 50 species for which 42 …
Diel Vertical Migration Of Zooplankton In The Tanzanian Waters Of Lake Victoria, Rk Waya
Diel Vertical Migration Of Zooplankton In The Tanzanian Waters Of Lake Victoria, Rk Waya
Tanzania Journal of Science
The diel vertical migration of zooplankton was studied in the Southern part of Lake Victoria in January and July 2002. A van dorn water sampler was used to collect zooplankton. In January 2002, zooplankton showed a pronounced diel vertical migration whereby zooplankton were moving upward at around sunset and swimming downward at sunrise. In July 2002 zooplankton showed diel vertical migration, but at around midnight Thermodiaptomus galeboides, Thermocyclops emini, Tropocyclops tenellus, cyclopoid copepodites, nauplius larvae and some rotifers showed downward movement. The diel vertical migration of zooplankton seems to be influenced by food, predation and light.
Preparations Of Spherical Polymeric Particles From Tanzanian Cashew Nut Shell Liquid By Suspension Polymerization, L L Mkayula, Y M M Makame, T H Matechi
Preparations Of Spherical Polymeric Particles From Tanzanian Cashew Nut Shell Liquid By Suspension Polymerization, L L Mkayula, Y M M Makame, T H Matechi
Tanzania Journal of Science
Spherical Polymeric Particles (SPP) have been prepared from Tanzanian Cashew Nut Shell Liquid (CNSL) by suspension polymerization technique involving either step-growth or chain- growth polymerization mechanisms. The sizes of the SPP, which ranged from 0.1 to 2.0 mm were strongly influenced by the amounts of stabilizers in polymerization recipes used. The particles showed variable surface areas, indicative of the presence of pores in some of the preparations and the highest surface area recorded was about 260 m2g-1. The particles were found to exhibit Langmuir-type adsorption isotherms with saturation capacity of about 9.0 and 44.2 mg/g for Na+ and Ca2+, respectively. …
Total Mercury Concentration In Common Fish Species Of Lake Victoria, Tanzania, J F Machiwa
Total Mercury Concentration In Common Fish Species Of Lake Victoria, Tanzania, J F Machiwa
Tanzania Journal of Science
Total mercury (THg) concentration was analysed in muscles of common fish species of Lake Victoria in the eastern and southern parts of the lake using cold vapour Atomic Absorption Spectrophotometric technique. Mercury concentration in all fish species was generally lower than the WHO maximum allowable concentration (500 ng/g ww) in edible fish parts. The maximum concentration of THg in Lates niloticus samples was 396 ng/g ww. Samples of Oreochromis niloticus had THg concentration ranging between <0.01 and 419 ng/g ww. Clarias gariepinus had THg concentration ranging between 1.2 and 239.1 ng/g ww. All less common fish species, such as, Labeo victirianus, Synodontis victoriae, Oreochromis leucostictus, Schilbe intermedius, Brycinus jacksonii, B. sadleri, Tilapia rendalii, Tilapia zilii and Haplochromines had THg concentration below the WHO maximum allowable limit (500 ng/g ww). The study showed that Hg from small-scale gold mining activities in Lake Victoria basin is not transported to the lake by fluvial discharge. Other possible pathways of Hg input to Lake Victoria are discussed.
Contamination Of Water And Sediments By Obsolete Pesticides At Vikuge Farm, Kibaha Distric, Tanzania, M J Mihale, M A Kishimba
Contamination Of Water And Sediments By Obsolete Pesticides At Vikuge Farm, Kibaha Distric, Tanzania, M J Mihale, M A Kishimba
Tanzania Journal of Science
Sediments and water from Vikuge State Farm, Coast Region, Tanzania, where, in 1986, a “donation” of 170 m3 of partially expired pesticides were stored in an open shed- which eventually collapsed, were analysed for 80 different pesticide residues and metabolites. DDT and HCH, two of the most persistent organochlorines pesticides, were the most dominant pesticides found in both matrices. In sediments the levels were up to 99,620 mg/kg dry weight of ΣDDT and up to 7,400 mg/kg dry weight of ΣHCH. The mean total HCH concentrations were 0.95 μg/l in tap water, 0.28 mg/l in surface water and 3.09 μg/l …
Studies On The Fisheries And Biology Of Oreochromis Urolepsis (Pisces: Cichilidae) In The Mtera Resorvoir (Tanzania), F M M Chale
Studies On The Fisheries And Biology Of Oreochromis Urolepsis (Pisces: Cichilidae) In The Mtera Resorvoir (Tanzania), F M M Chale
Tanzania Journal of Science
The fisheries and some aspects of the biology of Oreochromis urolepis of the Mtera Reservoir (Tanzania) were examined in August 2002. It was observed that there was no proper management of the reservoir's fisheries. Beach seine fishing dominated the fishery. Nearly all the O. urolepis caught by this type of gear were juveniles. The number of fish caught by the beach seines was very high, some times up to 4,000 fish per haul. The beach seines also destroy the spawning sites for the tilapias. Mean total lengths of O. urolepis caught in gillnets of legal mesh sizes (ranging from 88 …
Performance Analysis Of Cdma-Based Wireless Communication Systems Using The Simplified Improved Gaussian Approximation Method, H N Kundaeli
Performance Analysis Of Cdma-Based Wireless Communication Systems Using The Simplified Improved Gaussian Approximation Method, H N Kundaeli
Tanzania Journal of Science
The limitations initially prevalent in CDMA-based systems have been gradually solved thereby making CDMA a very promising access mode for future communication systems. Following the move towards higher data transmission rates, however, a number of other problems have emerged that need to be tackled. As a result, current world-wide research on CDMA-based systems is geared towards high speed, highly mobile multimedia communication applications. In this paper, the performance of a multi-user DS-CDMA communication system operating in a Rayleigh fading environment is investigated. Performance expressions are derived and the variation of the performance with various system parameters is presented.
Changes In Population Structures Of The Major Species In Selected Satellite Lakes Around Lake Victoria Following Changes In Fishing Effort, E F B Katunzi, M A Kishe
Changes In Population Structures Of The Major Species In Selected Satellite Lakes Around Lake Victoria Following Changes In Fishing Effort, E F B Katunzi, M A Kishe
Tanzania Journal of Science
This paper evaluates the impacts of reduction in effort, increase in mesh sizes, and prohibition of illegal fishing gears in selected satellite lakes around Lake Victoria. The study was carried out in six satellite lakes by making investigations on fish collected from experimental and artisanal fisheries. The fishes were analysed for length frequencies, weight and numbers caught to determine the population structure of the fishes. Indiscriminate fishing by deploying illegal gears and increased fishing effort due to open access policy, the catch and diversity of the species in these lakes has declined. Establishment of Conservation Management Units (CMUs) as an …
A Comparison Of Shell Size And Meat Weight Between Population Of The Bivalve Anadara Antiquata (Linnaeus 1758) From Four Sites Experiencing Different Levels Of Exploitation Pressure In Zanzibar, J P Shunula
Tanzania Journal of Science
A comparative study on the shell size and meat weight between Anadara antiquata populations harvested from four intertidal mud flats subjected to varying exploitation pressure in Zanzibar was undertaken between August and December 2000. An analysis of the data from the four study locations Mazizni, Mbweni, Kisakasaka, and Jambiani showed that much smaller sized Anadara , with low meat weights were being harvested from Mazizini and Mbweni in comparison to those harvested from Kisakasaka and Jambiani. The first two sites were areas in which there was heavy exploitation of the animals in comparison to the last two. Mazizini and Mbweni …
Elemental And Isotopic Compositions Of Organic Carbon And Nitrogen Of Recently Deposited Organic Matter In Empakai Crater And Its Implication For Climatic Changes In Northern Tanzania, A N N Muzuka
Tanzania Journal of Science
A 29 cm long core recovered from a water depth of 5 m in a small closed lake located in the Empakai crater northern Tanzania, is used to document the contents of organic carbon and nitrogen, stable isotopes composition of organic carbon and nitrogen, and C/N ratios and to infer climatic changes from these data. The δ 13C and δ15N values for this core, which averages - 16.5±2.1l and 11.0±5.6l respectively, show a general downcore decrease below 5 cm. However, within this general trend, two peaks enriched in 13C are observable at about 8 cm and 13 cm. The peak …