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Item Seasonal variation of Primary productivity and Small Pelagic Fish Catches along the western Coast of Pemba Island.(University of Dar es salaam, 2020) Kizenga, H. JSeasonal variation of Primary productivity and Small Pelagic Fish Catches along the western Coast of Pemba Island. Hellen Joseph Kizenga Master of Science in Marine Science University of Dar es salaam, Institute of Marine Science, 2020. Understanding the relationship between phytoplankton and fisheries productivity is very crucial in identifying potential areas for fishing. This study aimed at determining the seasonal variation of primary productivity and small pelagic fish catches along the Western coast of Pemba Island waters. The data used for this study included: (a) Remotely- Sensed Data-Chlorophyll-a (Chl-a) and Sea Surface Temperature (SST) (b) in-situ measured data- Dissolved Oxygen (DO) Total Suspended solids (TSS), pH, Salinity, SST, Phosphates and nitrates (c) the small pelagic fish catch (landings ) data, and (d) qualitative information- Key Informant Interview (KII) and Nominal Group Technique (NGT). The satellite derived measurements along with the fish catch data were collected over an extended period of 8 years (2011-2018). The in-situ measured data were acquired on seasonal basis that is, the Northeast (NE) and Southeast (SE) monsoon season for duration of 2 weeks during each season. The results showed that both the in-situ and satellite Chl-measurements were higher during the (SE) Monsoon than during the NE monsoon season. Similarly, DO,TSS, phosphates and pH were significantly higher during the SE MONSOON season. In contrast, SST, salinity and nitrates were significantly higher during the NE Monsoon season than during the SE Monsoon season. Chl-a and SST showed a strong negative correlation (R=-07, P<0.05). The results of the analyses of the relationship between fish catches and environmental parameters revealed that sardines and mackerel were significantly positively correlated with Chl-a at a 1-month lag (RIIag = 0.7, p<0.05) =08, p<0.05), respectively. Furthermore, anchovies displayed a strong correlation with Chl-a at 4-months’ time lag (R4lag =0.8, p<0.05). From the presented results, it was concluded that the relationship between small pelagic fish catches and environmental parameters (Chl-a and SST) was species dependent. The catches of common small pelagic fish groups such as mackerel and sardines were favored by the abundance of phytoplankton productivity. Anchovies were the exceptions. This would therefore call for different management strategies for the two categories of pelagic fish.Item Fisheries status and management aspects of octopus in Unguja Island, Zanzibar; the case of Kizimkazi mkunguni and Uroa areas(University of Dar es Salaam, 2020) Khamis, Amina UssiThe study was conducted to assess the fishery status and management aspects of octopus in Unguja Zanzibar, using Kizimkazi Mkunguni as a managed site and Uroa as unmanaged site. The study used longitudinal mixed method design comprises both qualitative and quantitative approaches within longitudinal method. Data was collection over a period of 2 months from April to June 2018. Primary data were collected through questionnaires, key informant interviews, and focus group discussion. Secondary data were collected from online literature, octopus management reports and unpublished data from the Department of Fisheries Development, Zanzibar. In order to examine the catch status and management aspect of octopus fishery, information on total catches landed, fishing effort, methods and gears used, income earned by fishers and distribution of the fishing grounds along the study sites were collected. The findings of the study revealed that generally, the unmanaged (Uroa) site was found to have a larger number and larger sized octopus compared to the managed site (Kizimkazi Mkunguni). Among the factors found to influence the changes includes; fishing methods and gears used size of fishing area and management system. The numbers of foot fishers were higher compared to divers; however, divers were found to catch bigger octopus with regard to size and weight. The study also found that the octopus closure system has management benefits, as significant increase in catches of octopus was observed after opening of the closure area, although these benefits were observed to last only a few days. The study highlights the need for proper management and constant monitoring on the catch trend of octopus. It also stresses the need for effective law enforcement, awareness rising to local communities, and equips SFC with training and financial support to sustain the octopus closure system in ZanzibarItem Growth performance, survival and community perspective on sponges farmed in Jambian, Zanzibar- Tanzania(University of Dar es Salaam, 2019) Hamad, Asma AhmadaSponges are important components of marine benthos worldwide. While efforts continue to develop methods for large-scale production of bath sponge, the global supply is too low to satisfy the demand. The present study explored the growth performance, survival and community perspective on sponges farmed in Jambiani, Zanzibar Tanzania. The experiment was set to investigate growth and survival of two commercial both sponges Agelas mauritiana var. oxeata and Callyspongiidae sp using off-bottom and floating raft culture methods. Water displacement method was used to determine initial and final volume of sponges to assess their growth. Household questionnaire survey, focus group discussion and key informant interviews were used collect data on community awareness and perspective towards sponge farming. Descriptive statistics of mean and percentage were used. A multiple comparison test (post hoc analysis) was used to determine variation in survival and growth of sponges between the methods used. Results revealed that, final survival of Callyspongiidae sp varied significantly between farming methods (p<0.05) compared to Agelas Mauritian var. oxeata (p>0.05) Overall, the highest species survival was observed in floating raft method. In contrast, growth of Callyspongiidae sp in floating raft was higher than Agelas mauritiana var. oxeata farmed in both methods. The results showed that a large part of community were aware of sponge farming and are supportive. However, the study suggests that, introduction of sponge farming should not be taken up lightly; there are issues of importance to be considered which include long-term research of ecological feasibility with innovative methods and in-depth social feasibility study.Item Levels and distribution polycyclic aromatic hydrocarbons (PAHs) in interstitial water, surface sediments and Oysters from the intertidal areas of Dar es Salaam, Tanzania(University of Dar es salaam, 2007) Gaspare, LydiaInterstitial water, surface sediment and oyster samples from the intertidal areas of Dar es Salaam, Tanzania were analysed to determine the level and distribution of PAHs. Samples were extracted using shaking and Accelerated Solvent Extraction methods and cleaned up using column chromatography. Samples were analysed using GC/MS. The concentration of PAHs in interstitial water ranged from 47.15 ng/1 and in sediment ranged from 56.41 ng/g dry weight (dw) to 14815.84 ng/g dw. The concentration between sediment PAHs concentration was positively correlated to sediment fine grain size of <63 um (r=0.68, n= 18, p<0.05). the concentration of PAHs in oysters ranged from 16.82 ng/g dw. Oyster samples were enriched with 2-3 ring PAHs by 40 % of total PAHs at all sampling stations except at Ocean Road which had 31.4 % 2-3 ring PAHs. The results showed that Ocean Road was highly polluted by PAHs followed by Mzinga creek. Lowest levels of PAHs were found at Kunduchi and Tegeta. Analysis of the possible sources of PAHs suggests petrogenis and pyrolyic dominated PAHs origins. It was concluded that sediment bound PAHs were not readily bioavailable to oysters and it is recommended that monitoring program be established for PAHs, so that any exceedance in concentration overenvironmental quality standards can be detected and appropriate actions be taken.Item Dynamics in Shirati Bay, Lake Victoria Tanzania With Special Zooplankton Emphasis on the Copepods(University of Dar es Salaam, 2008) Waya, Revania KiduduyeThe population of dynamics of zooplankton with emphasis on the copepods were studied Shirati Bay, Lake Victoria, between March 2005 and March 2006. The study revealed spatio-temporal variations in zooplankton distribution and the factors influencing their distribution, abundance and composition. Factors affecting zooplankton density, biomass and distribution in Shirat Bay were found to include food condition, predation, temperature, wind, light and transparency. There was significant correlation between zooplankton abundance and the bacillariophytes (r = 0.9454,n=13,p<0.0001),Rotifera biomass and cyanophytes (r=08264, n =13,p<0.0001)there was a significant association between abundance of fish and zooplankton (Matel test: Standard normal Variate g(1,1000)=7.0834, p=0.009,r=0405, and abundance of haplochromines and zooplankton (g 1,1000) = 6.348, p=0.001,r = 0.888). also the linear correlation analysis revealed significant correlation between temperature and number of ovigerous female copepod (r= -05585, n=13, p=0.0473). three groups of zooplankton were recorded namely, Copepoda, Rotifera, and Cladocera. A total of 44 species were recorded, Rotifera showed highest diversity index (H’) of 2.321. Copepoda was the most important group in terms of abundance and biomass among them cyclopoid copepod dominated the zooplankton community throughout the study period. Nauplius and Cyclpopoid Copepodites in Shirati Bay During March 2005 –March2006 0 MAR-05 APR 05 MAY 05 JUN 05 JUL 05 AUG 05 SEP 05 0CT 05 N0V 05 MAR O5 0.000 0.741 0.647 0.816 0.789 0.800 0.989 0.929 APR 05 2.770 0.000 1.000 1.000 1.000 1.000 1.000 1.000 MAY 05 3.010 0.240 0.000 1.000 1.000 1.000 0.997 1.000 JUN 05 2.558 0.212 0.451 0.000 1.000 1.000 1.000 1.000 JUL 05 2.639 0.131 0.371 0.081 0.000 1.000 1.000 1.000 AUG05 2.606 0.164 0.404 0.048 0.033 0.000 1.000 1.000 SEP 05 1.624 1.146 1.386 0.935 1.015 0.983 0.000 1.000 OCT 05 2.139 0.631 0.871 0.419 0.500 0.467 0.515 0.000 NOV 05 1.324 1.446 1.686 1.234 1.315 1.282 0300 0.815 DEC O5 2.807 0.037 0.203 0.249 0.168 0.201 1.183 0.668 JSN 05 0.220 2.550 2.790 2.339 2.419 2.386 1.404 1.919 FEB 06 3.755 6.525 6.765 6.313 6.394 6.361 5.378 5.894 MAR 06 1.754 4.524 4.764 4.312 4.393 4.360 3.378 3.893 Values in bold indicate significant differences among months.Item Feeding ecology energetics of two sympatric jackal species in the Ngorongoro crater, Tanzania(University of Dar es Salaam, 2016) Temu, Steven ElisameheIt is energetically costly for a carnivore to travel long distances or spend a lot of time searching for food without securing enough nutrition for survival and reproduction. Feeding ecology energetics of two sympatric jackal species (golden jackal, Canisaureus and silver-backed jackal, Canismesomelas) was studied by both direct observation of focal animals and indirectly by scat analysis of known individuals. The research was done in the Ngorongoro crater between July 2014 and May 2015, a period that covered both dry and wet seasons. The results revealed that diets of both jackal species were broadly similar in the dry season and included carrion, insects, rodents and plant material while in the wet season the two species also consumed Thomson’s gazelle fawns. Furthermore, the golden jackal also fed on wildebeest placental and hunted for Abdim’s stork during the wet season. This seasonal variation in diets reflects seasonal availability of food items in jackal’s home ranges confirming the opportunistic feeding habit of the two jackal species. There was no significant difference in distance travelled per unit time of foraging between the two species in the dry season and in wet season. However, in the wet season, golden jackals secured significantly higher amount of food (per distance and time of foraging) than the silver-backed jackals (Mann- Whitney U test, p<0.05, U=1035.4, n1=35, n2=44). Effecicient foraging is very important especially in breeding seasons as more food is needed for survival of pups. It is recommended that future studies be conducted outside the crater within Ngorongoro Conservation Area where the jackals are also known to occur. NCAA should consider allowing the night data collection in future studies to enable both day and night sampling of the jackals in order to have better information on the sympatric jackals at night since the animals are known to be active at night too. Key words: Canisaureus, Canismesomelas, efficient foraging, Ngorongoro crater, opportunistic feeding, sympatricItem Seasonal distribution and abundance of the common carangid fishes found in Unguja island (Zanzibar) coastal waters, Tanzania(University of Dar es Salaam, 2016) Salehe, Hamis ShabaniThe study was carried out to investigate seasonal distribution and abundance variations, growth type and size structure of carangid fish species in Unguja Island coastal waters, Tanzania from April 2013 to March 2014. Sampling was done using catch assessment survey for adult and beach seining for juveniles. A total of 20 carangid species were identified, of which only 7 composed of sub-adult and adult fish and 4 of juveniles dominated. The most abundant species was Carangoides bajad with a composition of 31.2% with the highest peak in November, which coincides with North-East monsoon season and the least common species was Gnathanodon speciosus with 3.2% with highest peak in October. Juvenile Trachinotus blochii occurred year round and were found in sandy and sandy beach with some rockly outcrops whilst other carangid species were found seasonally in the sandy beaches and sandy-muddy habitats near the mangroves with peaks during the rainy seasons. The coefficient b of the length-weight relationships indicated negative allometric growth (b˂3) (p˂0.05) for juveniles, sub adults and adults of major species, except juvenile Caranx sexfasciatus which showed isometric growth (b=3). The overall sex ratios for seven major carangids were not significantly different from the expected value of 1:1 (p˃0.05). the length frequency distribution showed that six species were numerically dominated with fish sized ˂49 cm TL except C. sexfasciatus which is dominated with size ˃60 cm TL. These results will be convenient for fishery biologists and ecologists to recommend suitable guidelines for sustainable in the Zanzibar coastal waters, Tanzania and neighbouring countries.Item Mapping and characterization of fish landing sites and related infrastructures along the coast of Kinondoni and Bagamoyo Districts, Tanzania(University of Dar es Salaam, 2011) Semba, MasumbukoMapping artisanal fisheries activities for Bagamoyo and Kinondoni Districts based on spatial patterns of landing sites was carried out in a Geographic Information System (GIS) environment. Spatial attributes of the fish landing sites from fisheries frame survey database and field collected data was analyzed. The spat ial distribution of the fish landing sites was weighted using average nearest neighbour tool (ANNT. The ANNT revealed that fish landing sites were not scattered but statistically spatially dispersed (P<0.01) in the study area, and the hierarchy for the relative importance of the landing sites in the area was established. Msasani, Kunduchi and Custom were the most prominent ones. Moran I tool (MIT) showed a significantly high number of fishing vessels for fish landing sites at Kinondoni district (P<0.01). Analysis of the value of fish landing sites based on the price of filling vessels showed that Kunduchi had the highest investment value (532.65 Tsh Million), and was dominated by expensive fishing vessels (Boats), which constituted more than 52% of its total fishing vessel. Kunduchi was followed by Mlingotini (256.9 Tsh Million), and Msasani (152.05 Tsli Million), Nchipana(128.8 Tsh Million) and Custom (121.2 Tsh Million). It is important to highlight that price value of fishing vessels come from in situ data, while the number of fishing vessels come from fisheries frame survey database. Although, the number of fisheries records used for only ten fish landing sites, the study attempts to provide new insight on the spatial distribution, characteristic and investment value of landing sites, however, further studies will be needed to cover the whole coastline.Item Assessment of growth performance and feed utilization of the nile Tilapia (Oreochromis niloticus) fingerlings to pumpkin (Cucubrita Maxima) seeds meal as possible altenative fish feed to fish meal in Tanzania(University of Dar es Salaam, 2017) Kanyandenge, Zakaria MichaelThis study was designed to determine the effects on growth performance of feeding pumpkin seeds meal as a source of protein to Oreochromis niloticus. Triplicate tanks containing twenty specimens of Oreochromis niloticus of initial average weight of 0.37 ± 0.14 g to 0.43 ± 0.18 g were stocked per concrete tanks for 15 weeks. Three experimental diets each with 40 % crude protein and 1O % crude lipid were formulated and named as fish meal diet (FMD), mixture meal diet (MMD) and pumpkin seed meal (PSM) whereby diet named fish meal diet acted as a control diet without inclusion of pumpkin seeds. Fish were fed two times at rate of 10 % of their body weight per day. Data were analyzed by using one-way ANOVA. There was a significant difference in growth performance and feed utilization efficiency among experimental diets at significance level of 0.05 %. Fish fed fish meal diet (FMD) showed significantly higher average daily weight gain (0.16 ± 0.03 g), final body weight (5.68 ± 0.77 g) and specific growth rate (2.40 ± 0.77 g) followed by mixture meal diet with average daily weight gain (0.14 ± 0.02 g), specific growth rate (2.13 ± 0.63) and final body weight (4.64 ± 0.67 g). Low average daily gain of 0.13 ± 0.25 g and specific growth rate of 1.88 ± 0.44 were realized in pumpkin seed meal. The higher protein efficiency ratio (PER) of 2.59 ± 0.03 was obtained in fish meal diet followed by mixture meal diet (2.49 ± 0.03) and pumpkin seed meal diet (2.34 ± 0.04). Higher feed conversion ratio of 1.89 ± 0.05 was found in fish fed with pumpkin seed meal followed by mixture meal diet and fish meal diet with 1.77 each and survival rate was (SR) 77.87 %. Water quality parameter was within acceptable optimal level for fish growth and survival. The mean observed was water temperature (26.95 ± 0.44 °C), dissolved oxygen (6.8 ± 1.5 mg/L to 9.5 ± 0.3 mg/L) and water pH (7.84 ± 0.18). The result of total replacement of fish meal by using pumpkin seeds meal as dietary plant protein source in Oreochromis niloticus meals was negative.Item Genetic stock structure and life History of euthynnus affinis cantor (1849) and scomberomorus commerson lacepede (1800) fishes in the northern coastal waters of Tanzania(University of Dar es Salaam, 2016) Grayson, Johnson MshanaThe population genetic structure and life history traits of Kawakawa Euthynnus affinis Cantor (1949) and Narrow barred Spanish mackerel Scomberomorus commerson Lacepede (1800) in the northern coastal waters of Tanzania, Western Indian Ocean were studied using sequence analysis of mitochondrial DNA (mtDNA) control region. A 475bp and 500bp segment of the control region was sequenced and analyzed (38 and 46 samples of Narrow barred Spanish mackerel and Kawakawa, respectively). The study revealed high levels of haplotype and nucleotide diversities. Analysis of molecular variance (AMOVAL), nearest neighboring statistic (Sm) and exact test of genetic differentiation did not show evidence for population subdivision (p>0.005); hence a null hypothesis that studied fish species constitute a single genetic stock in the northern Tanzania coastal waters could not be rejected. The Tajima’s D and Fu’s Fs models showed a significant deviation from neutral condition (p<0.005), indicative of a recent population expansion. The study revealed a single clade of individual fish species, suggestive of similar genealogical history. The genetic data were also supported by life history traits, which revealed geographical similarities in the spawning patterns, size at maturity and fish condition. In addition, number and size of eggs (µm) for females collected from Dar es Salaam was not statistically higher than those from Pangani (p>0.005). The Presence of genetic similarities for studied fish species was a result of gene flow, short geographical distance (IBD) and homogeneity in environmental distances (IBED, p>0.005). A single-stock model and regional shared management along with further similar research covering the whole Indian Ocean is therefore recommended.Item Genetic stock structure and life History of euthynnus affinis cantor (1849) and scomberomorus commerson lacepede (1800) fishes in the northern coastal waters of Tanzania(University of Dar es Salaam, 2016) Grayson, Johnson MshanaThe population genetic structure and life history traits of Kawakawa Euthynnus affinis Cantor (1949) and Narrow barred Spanish mackerel Scomberomorus commerson Lacepede (1800) in the northern coastal waters of Tanzania, Western Indian Ocean were studied using sequence analysis of mitochondrial DNA (mtDNA) control region. A 475bp and 500bp segment of the control region was sequenced and analyzed (38 and 46 samples of Narrow barred Spanish mackerel and Kawakawa, respectively). The study revealed high levels of haplotype and nucleotide diversities. Analysis of molecular variance (AMOVAL), nearest neighboring statistic (Sm) and exact test of genetic differentiation did not show evidence for population subdivision (p>0.005); hence a null hypothesis that studied fish species constitute a single genetic stock in the northern Tanzania coastal waters could not be rejected. The Tajima’s D and Fu’s Fs models showed a significant deviation from neutral condition (p<0.005), indicative of a recent population expansion. The study revealed a single clade of individual fish species, suggestive of similar genealogical history. The genetic data were also supported by life history traits, which revealed geographical similarities in the spawning patterns, size at maturity and fish condition. In addition, number and size of eggs (µm) for females collected from Dar es Salaam was not statistically higher than those from Pangani (p>0.005). The Presence of genetic similarities for studied fish species was a result of gene flow, short geographical distance (IBD) and homogeneity in environmental distances (IBED, p>0.005). A single-stock model and regional shared management along with further similar research covering the whole Indian Ocean is therefore recommended.Item The reproductive biology of the squid, sepioteuthis lessoniana ( lesson, 1830 ) in the coastal waters of Zanzibar.(University of Dar es Salaam, 1997) Mhitu, Hassan AhmedA study on the reproductive biology of the bigfin reef squid, Sepioteuthis lessoniana f Lesson, 1830) in the coastal waters of Zanzibar, was conducted with a view to obtaining basic information that will be relevant to proper management of the squid fishery in the area. Data collection involved field sampling and laboratory work. A total of 664 specimens of the species were collected from artisanal fisheries at Chwaka, Zanzibar during 1994/1995. The body weight and the morphometric length measurements (DML, FW and FT) of S. lessoniana taken before and after freezing had no significant difference (P>0.05). However, the difference between the measurements made on 20 specimens while fresh and after freezing was less than 4%. The maximum size of S. lessoniana was 347 mm DML and 277 mm DML for males and females, respectively. The minimum size for males was 63 mm DML and 72 mm DML for females. The maximum weight was 1617.3 g for males and 969 g for females whereas the minimum weights were 20.8 g and 26.3 g for males and females, respectively. Mature squids migrate from the coastal waters from July to offshore waters to spawn. The length-weight regression equations were: Males W=0.0005L2547 , Females W=0.0004L2576 and Combined W=0.0005L2 555. The slopes for length-weight regression lines for both males and females showed no significant difference (P>0.001) when compared. Both male and female S. lessoniana exhibited allometric growth. The mean condition factor was generally higher for females than for males in all months except for August. Females were therefore heavier than males. Sexual dimorphism was evident in this species where 344 females and 320 males were identified. Sex ratio in S. lessoniana was not significantly different from 1:1 throughout the year except in May, June and November. Two maturity indices, the gonadosomatic index (GSI) for both sexes, and the ratio of nidamental gland length to dorsal mantle length (NGL/DML ratio) for females coincided in their peaks in July. This coincidence may imply that, the individuals were mature and were ready to spawn. Statistical and graphical methods were used to determine size at maturity. Size at maturity for S. lessoniana was 138.9 ± 6.4 mm DML for males and 162.9 ± 4.3 mm DML for females through the statistical method. The graphical method yielded 149.5 mm DML and 162.8 mm DML for males and females, respectively. The estimated fecundity for female S. lessoniana from Zanzibar ranged from 450 to 1180 with a mean of680 eggs for individuals of 140 mm to 249 mm DML. The number of eggs in a capsule was 6 and mean size of the eggs was 6 mm in length and 4.5 mm in breadth. Fecundity was related to the size of the female.Item Ecology of the intertidal zone of selected sandy/muddy shores in the Dar es salaam area(University of Dar es Salaam, 2000) Mlay, Angela PeterAn ecological study was conducted on four shores in the Dar es Salaam area, Kunduchi, Ocean Road, Mjimwema/Kendwa, and Mtoni. The following were determined monthly for a period of one year: particle size, organic matter content, and percent pore water of the substrate; depth of the hydrogen sulphide layer; temperature; salinity; dissolved oxygen concentration in tidal pool water; and density, biomass, and species diversity of benthic macrofauna. In a comparison of the four shores, there was a very significant difference in density (randomized block analysis of variance, F = 22.751, p = 3.609 x 10"8), and biomass (Friedman’s test, Chi-square = 23.900, p = 2.576 x 105). Kunduchi and Ocean Road were similar in all the abiotic factors measured. Both shores had moderate species diversity, but low density and biomass of macrofauna. Besides being under environmental stress due to desiccation, these shores have been exposed to anthropogenic impacts due to excessive movement of boats and people, destructive fishing methods and pollution. In comparison with Kunduchi and Ocean Road, Mjimwema/Kendwa had higher percent pore water, lower organic matter content, thinner hydrogen sulphide layer, but approximately the same dissolved oxygen and salinity levels. Due to the physical contours of the surrounding area, this shore never completely drains and there are relatively few anthropogenic effects. Compared to the other three shores, Mjimwema/Kendwa had the highest biomass and species diversity of macrofauna. It also had high density. At Mtoni, the substrate was determined to be very fine silt, poorly sorted, with very low percent pore water, a high build up of organic matter, and a thick hydrogen suphide layer. Since it is in an estuary, salinity was lower than on the other shores and showed the greatest drop during the rainy season. Compared to the other three shores, Mtoni had the lowest species diversity, lowest biomass, yet highest density. This was due to the high density of two species of very small organisms that seem to be adapted to that stressful environment, i.e., Arcuatula arcuatula and Modiolus sp Mtoni had greater biomass of bivalves, crabs, and polychaetes than on the other shores. Gastropods were found in the greatest biomass at Mjimwema and were not observed at all at Mtoni. Total macrofauna, bivalve, and polychaete biomass were highest during the principal and secondary rainy seasons at Mjimwema/Kendwa. Crabs had greater biomass during the principal rainy season at both Ocean Road and Mjimwema/Kendwa. Kunduchi and Ocean Road showed the greatest biomass on the lower part of the shore, while Mjimwema and Mtoni showed the greatest biomass in the middle of the shore. All shores showed the lowest biomass on the upper part of the shore, which was dominated by crabs. In this zone, Dotilla fenestrata was dominant on all shores along with either Ocypode spp. (Kunduchi, Ocean Road and Mjimwema) or Uca spp. (Mtoni). At Kunduchi and Ocean Road, midshore was dominated by a variety of polychaetes, sipunculids, bivalves and crabs, while holothurians dominated the lower shore. At Mjimwema/Kendwa, midshore was dominated by a variety of gastropods, bivalves, sponges, holothurians, sea urchins, and brittle stars.Item The effects of exploitation on habitat, reproductive potential and assessment of knowledge for management of sea cucumbers (echinodermata: holothuria scabra and h. nobilis) in Tanzania(University of Dar es Salaam, 2017) Mmbaga, Twalibu KithakeniWhile the impacts of high exploitation on fish populations and aquatic ecosystems are well documented for commercial and small-scale fishing particularly in the marine environment, such impacts on the fishery of sea cucumbers have not received as much attention. The current thesis examines the impacts of exploitation on sea cucumbers’ basic ecological, biological, fishery, and knowledge of management aspects by focusing on Holothuria scabra and H. nobilis. The study sites selected are associated with different exploitation intensities and pronounced selective exploitation along the coast of Tanzania. The impacts range from effects on the habitats (diminished natural ecological parameters, habitat modifications, and habitat disturbance), exploited population (size, structure, and reproductive potential), changes in fishery characteristics (gear, and fishing methods), to lack of biological knowledge for management. The main findings of the study are that, fishers of sea cucumbers fall under four categories, namely collectors, processors, middlemen and exporters. Middlemen are either fishers of sea cucumbers or rich non-fishers/dealers. Sea cucumbers fishing, associated activities and mismatch between stakeholders and knowledge have led to a decline in habitat quality, species abundance, and reproductive potential. The study further showed that fishery characteristics and knowledge for management of fishers are affected. In conclusion, management options (closed areas, closed season) for sustainable sea cucumber fisheries and areas for future research are outlined, with an emphasis on co-operation from all stakeholders in terms of knowledge, experience and actions (indigenous knowledge and experience, scientists and government help) to ensure livelihood success. It is recommended that stakeholders in the management processes should include government, exporters, marine and fishery researchers, grant/funding agents, leaders and fisheries extension officers.Item Temporal and spatial variation in stable isotope and heavy metals in sediment and coral reef of the coastal marine areas of Tanzania(University of Dar es Salaam, 2017) Ilomo, Ophery OziasTrace metals concentrations, carbon and total nitrogen contents, coral growth rates, CaCO3 content, Sr/Ca ratio, δ13C, δ15N and δ18O of both the bulk sediment and coral cores retrieved mainly between the land and the fringing reefs off Dar es Salaam City and off Zanzibar Town were used to (i) assess levels of contamination; (ii) document temporal and spatial variation in anthropogenic perturbation of the marine environment and (iii) reconstruct sea surface temperature (SST) on different timescales. The results showed metal concentrations in both sediments and coral samples were significantly higher off Dar es Salaam as compared to Zanzibar sites (P<0.01). The elevated degree of heavy metals contamination (Cd>2) and enrichment (EF>1) suggesting an increase in anthropogenic pollution resulting from discharge of untreated industrial and domestic effluents. The δ13C and δ18O averaging 1.18‰ and 1.79 ‰ respectively were more enriched in 13C and 18O, suggesting that the sediment contains carbonate originating mainly from marine shallow waters. Lower enrichment of 15N (average 1.96 ‰) were probably due to low primary productivity and inflow of terrestrial sources in the Zanzibar channel. The Porites coral growth rate was between 7 to 12 mm yr-1 and SST variability was observable. The lowest SST was in the year 1710 probably representing the little ice age. The reconstructed and recent instrumental SST data are positively correlated (r=0.7, P<0.01). Remarkable temporal increase in N-content in corals (0.01 to 0.30%) and the elevated δ15N at Tanga (7.04‰) and Dar es Salaam (9.78‰) might be due to anthropogenic activities. Authorities are advised to establish a strict industrial and domestic effluents management framework to municipalities and industries to prevent further pollution.Item Land use conflicts and their implications on wildlife management in Ugalla ecosystem- western Tanzania(University of Dar es Salaam, 2017) Hochi, Rajabu ShabaniLand use conflict is a global wildlife management challenge. Understanding ecosystem specific patterns of land use are a key to addressing this challenge. The study assessed land use conflicts and their implications on the management of wildlife in the Ugalla ecosystem in Western Tanzania. Literature review, household survey, focus group discussions, key informant interviews methods and direct observations were used to collect data in two villages each from Urambo and Sikonge Districts. A total of 68 head of household and about 15 key informants were interviewed. Methods used for data analysis included Statistical Package for Social Science (SPSS) and Microsoft excel. Findings from the study has revealed that, there are different categories of land use conflicts such as wildlife authority versus pastoralist, farmers versus livestock keepers, investors versus communities and livestock keepers among themselves. Most of these conflicts are caused by competition for natural resources such as pasture land, water point and land for agricultural activities. Other causes include conflicting policies such as wildlife, livestock, land and agricultural policies to mention but a few. However, land use conflicts has resulted into decline of some wildlife species, encroachment into protected areas and unwilling of local communities to support wildlife conservation. Different initiatives has been undertaken to resolve land use conflicts including political leader mediation and meeting with traditional and cultural leaders. This study has concluded that there is frequent land use conflict in Ugalla ecosystem due to completion for land and other natural resources such as wildlife. It is recommended that further studies should be undertaken to assess the significant impacts of land use conflicts by looking at the wildlife population trend and land use cover change for the period between 10 to 20 years in Ugalla Ecosystem.Item Socio-economic determinants of mangrove exploitation and management in Pangani River Estuary, Tanzania(University of Dar es Salaam, 2017) Nyangoko, Baraka PaulMangroves in Tanzania are gazetted forest reserves, albeit they continue to be threatened by human pressures and mismanagement. This study explored socio-economic determinants of exploitation patterns and management of mangroves in Pangani River Estuary, using two communities of Bweni and Pangani Magharibi as case study sites. Data were collected through focus group discusions (FGDs), key informant interviews (KIIs), househould questionnaire (HHQ) and field observations. Quantitative data were analysed for both descriptive and statistical inferences while qualitative information was subjected to content analysis. Residence time of household, household main occupation, household size and cost of alternative resources to substitute use of mangroves as source of fuel wood were positively correlated with mangrove resource use. The two communities differed in perception on the role of local institutions in management of mangroves.Over 56% of respondents in Bweni agreed that interventions of Beach Management Units (BMUs) enhanced mangrove condition and only about 16% in Pangani Magharibi had similar perception. Overall, more than 50% of respondents were not impressed with effectiveness of state management agencies in implementing conservation measures and sustainable use of mangroves. Loss of coastal fisheries resources was perceived as the major negative impact of mangroves overuse. This study recommends promotion of feasible alternative livelihood activities especially to fishermen and improved stakeholders’ collaborative arrangements for sustainable exploitation and management of mangroves in the area.Item Ecophysiology of mangrove seedlings: Responses to Waterlogging, Salinity, Light and Nutrient Enrichment(University of Dar es Salaam,, 2012) Mangora, Mwita MarwaAlthough flooding and salinity variations occur commonly in mangrove systems, their frequency and severity have, however, been increasing with increased global warming (GW) to an extent that GW induced phenomenon such as heavy rainfall and subsequent floods, increased terrestrial runoff, and sea level rise are frequently associated with massive mangrove mortality and/or failure to regenerate. Manipulative mesocosm experiments were therefore set to assess the interactive stress effects of mimicked waterlogging/submergence, salinity, light and nutrient enrichment on growth and photosynthesis of seedlings of the mangroves Avicennia marina (Forssk.) Vierh., Bruguiera gymnorrhiza (L.) Lamarck and Heritiera littoralis Dryand. Three main experiments were conducted: (i) interactive effect of waterlogging, salinity and light, (ii) interactive effect of waterlogging, salinity and nutrient enrichment and (iii) underwater photosynthesis in varied salinities. Growth was assessed through structural and biomass traits, and photosynthesis through assessment of photosynthetic yield and leaf chlorophyll content. It was found that H. littoralis growth was drastically suppressed and its photosynthetic yield significantly declined during prolonged waterlogging and submergence, increased salinity, and when shifted from shade to light. Comparably, B. gymnorrhiza seedlings maintained high tolerance across the variably interactive stresses than A marina and H. littoralis. Nutrient enrichment did not provide enhancing effect to override the stressful conditions of waterlogging and elevated salinities. The varying ability of B. gymnorrhiza and A. marina to acclimatisation and the inability of H. littoralis to withstand the stresses suggest possible disruptions in mangrove forests regeneration in conditions of prolonged inundations due to flooding or sea-level rise. Results of the present study demonstrated that climate change driven environmental conditions may influence the performance of seedlings. They are useful in explaining the phenomenon of retarded natural regeneration in mangrove stands in major river estuaries of the region following flooding events, like that of 1997/98 El Nino. They are also useful in guiding management decisions on mitigation and adaptive mangrove restoration and management especially where reforestation and afforestation may be necessary.Item Modelling coral-corallimorpharia interaction under varying anthropogenic inputs along the coast of Tanzania(University of Dar es Salaam,, 2012) Rushingisha, GeorgeCoral reefs are valuable resources for humanity, but are increasingly threatened by natural and anthropogenic stresses. The increased corallimorpharian abundance on reefs located close to urban centers is alarming as it appears to outcompete and inhibit recruitment of corals. This study investigated the interaction between corals and corallimorpharians under varying anthropogenic inputs using observational, experimental and modelling approaches. The Line Intercept Transect method (LIT) was used to determine changes on corals, corallimorpharians, macro-algae, turf-algae and coral rubble and the changes were correlated to (a) water visibility (b) phosphate and (c) nitrate concentrations. Nutrients and iron were enriched within Porites and Rhodactis rhodostoma interactin plots. A cellular automata (CA) model was applied to investigate the interaction between corals and corallimorpharians under a nutrient gradient. Results indicated no significant changes on corals, corallimorpharians, turf-algae and coral rubble covers during the study period. Porites and Galaxea genera were found to be susceptible and not susceptible to corallimorpharians overgrowth, respectively. Corallimorpharians cover correlated positively to phosphate and nitrate concentrations but negatively to water visibility. The experimental results indicated higher R. rhodostoma growth rate in nutrient enriched plots (1.7cm/month) than controls with and without iron nail (0.5cm/month). The model showed that corallimorpharians spread was faster and their cover was higher on high nutrient zone. The study suggests nutrient as the major factor facilitating corallimorpharians overgrowth on corals. Therefore, coexistence between corals and corallimorpharians is only possible under low nutrient conditions.Item Molecular ecology and photo—physiology of symbiodinium harboured by Tanzania reef Building coral(University of Dar es Salaam,, 2012) Chauka, Leonard JonesEstablishment of symbiosis with thermal tolerant Symbiodinium type is widely believed to be amongst the functional adaptation mechanism employed by reef-building corals (RBCs) to bleaching. In this study, Symbiodinium types found in 66 most common RBC species have been studied together with photo-physiology of the selected corals and their respective Symbiodinium with a view to evaluate Tanzanian reefs' capacity to adapt to current trends of climate change. Internal transcribed spacer two (ITS-2) regions of nuclear ribosomal DNA genes (rDNA) was used to identify the symbiont types. In addition, changes in photosynthetic pigment concentrations and ratios, synthesis of ultra violet absorbing substances, changes in Symbiodinium types and abundances, maximum quantum yield (Fv/Fm) and excitation pressure on PS II (Qm) were used to assess responses of corals and/or their associated Symbiodinium types to both thermal and photo-radiations in situ and/or ex-situ. It was found that, Symbiodinium cells harboured by RBC from Tanzania do not constitute a distinct genetic group from those in other parts of the world. Although they were found to be thermal and irradiance susceptible, Symbiodinium C3u and C3z dominate in Tanzanian reef-building corals. Shuffling of algal symbionts that hypothetically provide corals with thermal resistance is limited to few Tanzanian RBCs. The renown high bleaching resistance of Porites cylindrica as compared with other species was found to -be contributed by its Symbiodinium C15's ability to synthesize significantly higher concentrations of both carotenoids and UV-absorbing compounds. Besides, this study recognizes the contribution of the host to this ability. It is generally concluded that the rate at which Tanzanian RBC develop adaptations to current trends of climate change is not enough to survive from devastating effects of bleaching. Because a reverse of current trends of climate change is not a possibility, this thesis recommends useful management information and an urgent need of alleviating local anthropogenic threats on Tanzanian coral reef ecosystems to enhance their resilience.