Sitoki L.,Kenya Marine and Fisheries Research Institute |
Sitoki L.,University of Innsbruck |
Kurmayer R.,Austrian Academy of Sciences |
Rott E.,University of Innsbruck
Hydrobiologia | Year: 2012
The Nyanza Gulf is a large shallow bay of Lake Victoria suffering from eutrophication by human activities. In order to characterize the harmful algal bloom formation as a consequence of eutrophication, both spatially and seasonally, environmental conditions, phytoplankton community composition, and microcystin (MC) concentrations were investigated monthly from Kisumu Bay, and bimonthly from the center of the gulf, as well as quarterly from the Rusinga Channel and the main basin of Lake Victoria between July 2008 and September 2009. The sites located in Kisumu Bay and the central gulf were most strongly affected by eutrophication, including increased nutrient concentrations and phytoplankton growth. More than 90% of the samples obtained from the gulf were dominated by cyanobacteria, whereas diatoms only dominated in the samples obtained from Rusinga Channel and the main lake. In general, Microcystis accounted for the largest part (>50-90%) of cyanobacterial biovolume. MCs were found in 35 (54%) out of 65 samples and were detected throughout the study period in the gulf, but only in two out of eight samples from the Rusinga Channel and the main lake. A significant linear relationship between Microcystis biovolume and MC concentration was observed (n = 65, R 2 = 0.88, P < 0.001). The highest MC concentrations were recorded in Kisumu Bay between November and March (max. 81 μg l -1) when Microcystis showed max. biovolume (18 mm 3 l -1 in November 2008). The results suggest that seasonal variability did not outweigh the spatial differences in phytoplankton composition and MC production, which is seasonally persistent in Kisumu Bay. © 2012 The Author(s).
Agency: GTR | Branch: NERC | Program: | Phase: Research Grant | Award Amount: 1.21M | Year: 2013
This project aims to better understand the links between ecosystem services (ES) and wellbeing in order to design and implement more effective interventions for poverty alleviation. We do this in the context of coastal, social-ecological systems in two poor African countries; Kenya and Mozambique. Despite recent policy and scientific interest in ES, there remain important knowledge gaps regarding how ecosystems actually contribute to wellbeing, and thus poverty alleviation. Following the ESPA framework, distinguishing ecological processes, final ES, capital inputs, goods and values, this project is concerned with how these elements are interrelated to produce ES benefits, and focuses specifically on how these benefits are distributed to (potentially) benefit the poor, enhancing their wellbeing. We thus address the ESPA goal of understanding and promoting ways in which benefits to the poorest can be increased and more people can meet their basic needs, but we also identify conflicted tradeoffs, i.e. those which result in serious harm to either the ecosystem or poor people and which need urgent attention. Several fundamental questions are currently debated in international scientific and policy fora, relating to four major global trends which are likely to affect abilities of poor people to access ES benefits: (1) devolution of governance power and its impacts on local governance of ecosystems and production of ES, (2) unprecedented rates and scales of environmental change, particularly climate change, which are creating new vulnerabilities, opportunities and constraints, shifting baselines, and demanding radical changes in behaviour to cope, (3) market integration now reaches the most remote corners of the developing world, changing relationships between people and resources and motivations for natural resource management, (4) societal changes, including demographic, population, urbanisation and globalisation of culture, forge new relationships with ES and further decouple people from direct dependency on particular resources. Study sites have been chosen so as to gather empirical evidence to help answer key questions about how these four drivers of change affect abilities of poor people to benefit from ES. We aim for direct impact on the wellbeing of poor inhabitants of the rapidly transforming coastal areas in Mozambique and Kenya, where research will take place, while also providing indirect impact to coastal poor in other developing countries through our international impact strategy. Benefits from research findings will also accrue to multiple stakeholders at various levels. Local government, NGOs and civil society groups - through engagement with project activities, e.g. participation in workshops and exposure to new types of analysis and systems thinking. Donor organizations and development agencies - through research providing evidence to inform strategies to support sector development (e.g. fisheries, coastal planning and tourism development) and methods to understand and evaluate impacts of different development interventions - e.g. through tradeoff analysis and evaluation of the elasticities between ecosystem services and wellbeing. International scientific community - through dissemination of findings via conferences, scientific publications (open access), and from conceptual and theoretical development and new understandings of the multiple linkages between ecosystem services and wellbeing. Regional African scientists will benefit specifically through open courses offered within the scope of the project, and through dissemination of results at regional venues. Our strategies to deliver impact and benefits include (1) identifying windows of opportunity within the context of ongoing coastal development processes to improve flows of benefits from ecosystems services to poor people, and (2) identifying and seeking to actively mitigate conflicted tradeoffs in Kenya and Mozambique.
Agency: European Commission | Branch: FP7 | Program: CP-FP-SICA | Phase: KBBE.2011.2.5-02 | Award Amount: 3.97M | Year: 2012
Food security is a major concern for all countries in the face of population increase and diminishing energy and water supplies. Over one billion people in low and middle income countries suffer from malnutrition. To meet the UN Millennium Development Goals to eradicate hunger and poverty, it is essential to reduce post harvest losses, including in the fisheries sector. The overall objectives of SECUREFISH are to strengthen capacity in low cost technology; to improve the preservation of existing fish supplies; to utilise waste and bycatch to produce value-added products; to develop an integrated quality management tool and finally to test the developed technology and quality management tool in different real third country conditions. There are six work packages (WP). WP1 will ensure the efficient management of the project. WP2 will develop low cost innovative processing tools based on traditional technology for preserving fish including a solar tunnel drier, a modified solar assisted extruder and fast freezing/ continuous atmosphere freeze-drier (CAFD). In WP3, underutilised bycatch and waste by-products of fish processing will be recovered and converted to high value products. WP4 will develop an effective total quality management tool (safety and risk assessment; HACCP quality cost and traceability, nutritional and eating quality and carbon footprint) of three fish product chains (solar dried, extruded and frozen/CAFD) which will be tailored to suit local needs. The technological advances (WP2) and quality management tool (WP4) will be evaluated in the three fish product chain case studies in Africa (Kenya, Namibia, Ghana), Asia (India and Malaysia) and Latin America (Argentina) to include different economic, cultural and social conditions. The case studies involve stakeholders including SMEs to ensure sustained implementation of project results. WP6 details a strategy for education, training and dissemination to widely promote the results and guidelines.
Agency: GTR | Branch: NERC | Program: | Phase: Research Grant | Award Amount: 1.10M | Year: 2015
East Africa (EA) has one of the worlds fastest growing populations, with maxima around water-bodies and rapid urbanisation. Climate change is adding to existing problems increasing vulnerability of the poorest. HyCRISTAL is driven by EA priorities. EA communities rely on rainfall for food via agriculture. EAs inland lakes are rain-fed and provide water, power and fisheries. For EAs growing cities, climate impacts on water resources will affect water supply & treatment. HyCRISTAL will therefore operate in both urban & rural contexts. Change in water availability will be critical for climate-change impacts in EA, but projections are highly uncertain for rain, lakes, rivers and groundwater, and for extremes. EA Long-Rains are observed to be decreasing; while models tend to predict an increase (the EA Climate paradox) although predictions are not consistent. This uncertainty provides a fundamental limit on the utility of climate information to inform policy. HyCRISTAL will therefore make best use of current projections to quantify uncertainty in user-relevant quantities and provide ground-breaking research to understand and reduce the uncertainty that currently limits decision making. HyCRISTAL will work with users to deliver world-leading climate research quantifying uncertainty from natural variability, uncertainty from climate forcings including those previously unassessed, and uncertainty in response to these forcings; including uncertainties from key processes such as convection and land-atmopshere coupling that are misrepresented in global models. Research will deliver new understanding of the mechanisms that drive the uncertainty in projections. HyCRISTAL will use this information to understand trends, when climate-change signals will emerge and provide a process-based expert judgement on projections. Working with policy makers, inter-disciplinary research (hydrology, economics, engineering, social science, ecology and decision-making) will quantify risks for rural & urban livelihoods, quantify climate impacts and provide the necessary tools to use climate information for decision making. HyCRISTAL will work with partners to co-produce research for decision-making on a 5-40 year timescale, demonstrated in 2 main pilots for urban water and policies to enable adaptive climate-smart rural livelihoods. These cover two of three areas of need from the African Ministerial Council on Environments Comprehensive Framework of African Climate Change Programmes. HyCRISTAL has already engaged 12 partners from across EA. HyCRISTALs Advisory Board will provide a mechanism for further growing stakeholder engagement. HyCRISTAL will work with the FCFA global & regional projects and CCKE, sharing methods, tools, user needs, expertise & communication. Uniquely, HyCRISTAL will capitalise on the new LVB-HyNEWS, an African-led consortium, governed by the East African Community, the Lake Victoria Basin Commission and National Meteorological and Hydrological agencies, with the African Ministerial Conference on Meteorology as an observer. HyCRISTAL will build EA capacity directly via collaboration (11 of 25 HyCRISTAL Co-Is are African, with 9 full-time in Africa), including data collection and via targeted workshops and teaching. HyCRISTAL will deliver evidence of impact, with new and deep climate science insights that will far outlast its duration. It will support decisions for climate-resilient infrastructure and livelihoods through application of new understanding in its pilots, with common methodological and infrastructure lessons to promote policy and enable transformational change for impact-at-scale. Using a combination of user-led and science-based management tools, HyCRISTAL will ensure the latest physical science, engineering and social-science yield maximum impacts. HyCRISTAL will deliver outstanding outputs across FCFAs aims; synergies with LVB-HyNEWS will add to these and ensure longevity beyond HyCRISTAL.
Feikin D.R.,Centers for Disease Control and Prevention |
Tabu C.W.,Centers for Disease Control and Prevention |
Gichuki J.,Kenya Marine and Fisheries Research Institute
American Journal of Tropical Medicine and Hygiene | Year: 2010
Cholera outbreaks continue to occur regularly in Africa. Cholera has been associated with proximity to lakes in East Africa, and Vibrio cholerae has been found experimentally to concentrate on the floating aquatic plant, water hyacinth, which is periodically widespread in East African lakes since the late 1980s. From 1994 to 2008, Nyanza Province, which is the Kenyan province bordering Lake Victoria, accounted for a larger proportion of cholera cases than expected by its population size (38.7% of cholera cases versus 15.3% of national population). Yearly water-hyacinth coverage on the Kenyan section of Lake Victoria was positively associated with the number of cholera cases reported in Nyanza Province (r = 0.83; P = 0.0010). Water hyacinth on freshwater lakes might play a role in initiating cholera outbreaks and causing sporadic disease in East Africa. Copyright © 2010 by The American Society of Tropical Medicine and Hygiene.
Mwamburi J.,Kenya Marine and Fisheries Research Institute
Lakes and Reservoirs: Research and Management | Year: 2016
No detailed studies have been conducted on the spatial distribution of sediment characteristics within Nyanza Gulf of Lake Victoria, especially after the invasion of water hyacinth. Accordingly, a rapid, inexpensive method was used to determine the spatial sediment organic matter variations, expressed as loss on ignition (LOI). Surficial sediments were collected during different survey periods from about thirty-two sampling sites between 1994 and 2012, in order to characterize the sediments. Although the deeper (>40 m) depositional areas are located in the open lake, visual observations indicate that most of the offshore sediments consist of muddy deposits, plus significant shell remains, with a more sandy type of sediments located in some areas off the inflowing river mouths. The surficial sediments were characterized by a relatively high water content, with over 89% of the samples containing water contents greater than 75%. The sediment organic matter contents from the 2012 survey were more variable, ranging from 1.90% to 33.47%. The sediment organic carbon contents varied spatially, although there were no significant variations between the different sampling periods. Evaluating the SOM at different heating durations at a constant temperature (550 °C) and a very high temperatures (950 °C) did not identify any significant differences. High primary production and greater settling in the deeper areas contribute to the nature of sediments deposited, also being reflected in the relatively high OC contents. Spatially, it is thought that detritus from water hyacinth and terrestrial external loads are important sources of organic matter deposited on the lake bottom within the gulf and may support its growth because of enrichment of nutrient elements. The importance of sediments in adsorption of contaminant substances and influencing geochemical processes within the lake is also emphasized. © 2016 John Wiley & Sons Australia, Ltd
Otwoma L.M.,Kenya Marine and Fisheries Research Institute |
Kochzius M.,Vrije Universiteit Brussel
PLoS ONE | Year: 2016
The coral reef sea star Linckia laevigata is common on shallow water coral reefs of the Indo-West Pacific. Its large geographic distribution and comprehensive data from previous studies makes it suitable to examine genetic differentiation and connectivity over large geographical scales. Based on partial sequences of the mitochondrial cytochrome oxidase I (COI) gene this study investigates the genetic population structure and connectivity of L. laevigata in the Western Indian Ocean (WIO) and compares it to previous studies in the Indo-Malay-Philippines Archipelago (IMPA). A total of 138 samples were collected from nine locations in the WIO. AMOVA revealed a low but significant ÖST -value of 0.024 for the WIO populations. In the hierarchical AMOVA, the following grouping rejected the hypothesis of panmixia: (1) Kenya (Watamu, Mombasa, Diani) and Tanzanian Island populations (Misali and Jambiani) and (2) the rest of the WIO sites (mainland Tanzania and Madagascar; ÖCT = 0.03). The genetic population structure was stronger and more significant (ÖST = 0.13) in the comparative analysis of WIO and IMPA populations. Three clades were identified in the haplotype network. The strong genetic differentiation (ÖCT = 0.199, P < 0.001) suggests that Indo-West Pacific populations of L. laevigata can be grouped into four biogeographic regions: (1) WIO (2) Eastern Indian Ocean (3) IMPA and (4) Western Pacific. The findings of this study support the existence of a genetic break in the Indo-West Pacific consistent with the effect of lowered sea level during the Pleistocene, which limited gene flow between the Pacific and Indian Ocean. © 2016 Otwoma, Kochzius. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Mbaru E.K.,Coral Reef Conservation Project |
Mbaru E.K.,Kenya Marine and Fisheries Research Institute |
McClanahan T.R.,Wildlife Conservation Society
Fisheries Research | Year: 2013
There is increasing effort to develop fishing methods that increase sustainability of the fishery and reduce bycatch without sacrificing the incomes of fishers. Consequently, we explored the use of modified African basket traps (experimental traps) retrofitted with 4. cm. ×. 30. cm escape gaps and compared their catches with those from unmodified traps lacking these gaps (controls). Studies were undertaken in a heavily fished Kenyan coral reef lagoon dominated by sand, seagrass, and coral reef. Of the 1202 fish captured, we distinguished 64 species from 23 families with significant differences in catch composition between the two trap types. Among the bycatch, numbers of butterflyfish and other low value species were reduced in the experimental traps. Overall, at the trap level, there were no significant differences in terms of mean length, weight and value of the target species. Nevertheless, fish captured in experimental traps were 31% longer and 55% heavier and a decline in the capture of low value species accounted for the lack of difference at the whole trap level. Due to a strong size-price relationship in this fishery, there was a 25% increase in the economic value of the gated compared to control traps. © 2013 Elsevier B.V.
Guya F.J.,Kenya Marine and Fisheries Research Institute
Lakes and Reservoirs: Research and Management | Year: 2013
Land-use changes have been implicated a lot in the eutrophication of many lakes while forgetting the role of internal loading as influenced by the hydrological regimes of a given lake. The phosphorus loading of Nyanza Gulf is influenced both by internal and external loading with the internal loading playing a greater role in its eutrophication. The shear on the Apatite Phosphorus (AP) rich residual rock in the western end of the gulf through strong currents across the Rusinga Channel erodes the rock into non-apatite inorganic phosphorus (NAIP) which is readily available for primary productivity. The current suspends the phosphorus rich apatite sediment together with the reserved phosphorus within sediments to the water column. The NAIP concentration on the western end of the gulf is exceptionally high, >1500 mg kg-1, and together with the hydrological forcing; is believed to be the driving force of Nyanza Gulf eutrophication. External loading through rivers and municipal discharges exacerbates the problem. The external loading mainly influences the inner gulf on the eastern shore while the internal loading affects mainly the western end of the gulf. Nyanza Gulf eutrophication can be managed by adopting the following measures: (i) the Mbita Causeway needs to be opened and a bridge erected in its place in order to reduce the strong current through the Rusinga Channel and the residence time within the gulf, by increasing the flushing rates; (ii) the farming communities within the basin need to be sensitized on the controlled use of fertilizers; (iii) the municipal wastes should be treated to tertiary level before discharge into the lake; and (iv) reduce erosion within the basin through re/afforestation. © 2013 Wiley Publishing Asia Pty Ltd.
Okuku E.O.,Kenya Marine and Fisheries Research Institute |
Okuku E.O.,Catholic University of Leuven |
Peter H.K.,Tanzania Fisheries Research Institute
International Journal of Environmental Research | Year: 2012
The study aimed to come up with a list of specific macroalgae species, which could be used to biomonitor specific metal elements in the coastal waters of East Africa. Water extraction, EDTA, aqua regia extraction and optimized BCR 3-step sequential extracts were used to mimic bioavailable metals under various environmental conditions. The results indicated that Ulva lactuca could be used as a biomonitor to predict BCR 3-step sequential bioavailable Al, Cd, Co, Fe, Mn, Zn and Ni whereas Sargassum species could be used as a biomonitor for BCR 3-step sequential bioavailable Co, Cu, Fe, Mn and Zn. In Sargassum spp. only Co showed significant correlation with concentration in sediment's aqua regia extracted metals whereas in Ulva lactuca only Al, Co, Cu and Fe showed significant correlation with total metals extracted through aqua regia procedure. This study therefore recommends the use of Ulva lactuca and Sargassum for biomonitoring of Al, Cd, Co, Fe, Mn, Zn, Ni and Co, Cu, Fe, Mn, Zn respectively. The study recommends the use of labile fraction of BCR sequential extraction for screening of macroalgae to be used for heavy metal pollution monitoring in East Africa region.