Recent Submissions

  • The Stock Assessment of the Kenyan Demersal Offshore Resources, Surveyed in the Period 1979-1980-1981 - Work Report no. 8. Project KEN/74/023 ”Offshore Trawling Survey”

    United Nations Development Programme; Food and Agriculture Organization of the United Nations; Goverment of Kenya, Ministry of Environment and Natural Resources (Kenya Fisheries Department, 1982)
    From February 1979 until June 1981 the trawler R/V Ujuzl surveyed the offshore Kenyan waters. The results of this vessel, supplemented by the results of three other trawlers, have been used for this stock assessment. The method used is the swept-area method. Three-level stratification has been applied. to all data (twelve fishing-grounds, two monsoon-period, fifteen groups of species). For the total trawlable surface of 3234 m2 (see charts 3 and 2), the total standing stock amounts to approximately 33,000 ton, the maximum sustainable yield is approximately 9,000 ton (the totals of table 4 plus the ”KUSI-area” plus the MESYATSEV-area). About half of these quantities consist of small fishes without any commercial value. The densities vary from 4.5 ton/m2 (MESYATSEV-area to 25.2 ton/m2 (stratum I). The results show further that, compared with other parts of the world, the productivity of the offshore demersal resources of Kenya is very low. A simple feasibility-study for each defined sub-area is added, showing that offshore trawling in Kenya is not profitable.
  • Notes on the Macro-benthos of Kenyan mangroves.

    Vannini, M.; Cannicci, S. (Museum of Zoology, “La Specola”, University of Florence, 1997)
    The notes were made for a post-graduate course in “Tropical coast ecology, management and conservation”, organised by Free University of Brussels and University of Nairobi, hosted at Kenya Marine and Fisheries Research Institute, with a support by IOC (Gazi, Mombasa, Kenya, July 1997).
  • Rehabilitation of the former Northern Swamp Lake Naivasha – Kenya. On the modeling of the sediment trapping efficacy for two rehabilitation alternatives.

    Cornelissen, M.A.J.M. (University of Twente, 2014)
    Erosion, induced by natural processes such as wind and rainfall and enhanced by anthropogenic activities such as agribusiness and deforestation, produces sediments that are carried downstream by rivers. The deposition of the sediments in the downstream areas creates new landmass for various life forms to live. However, the downstream deposition also causes problems such as sediment accumulation in delta regions and near boat ramps hindering navigation, and altering of the species composition affecting the ecological state. Erosion and the related problems also occur in the Lake Naivasha Basin, which is situated 80 km northwest of Nairobi in Kenya. The siltation affects the turbidity of the water with indirect influences on water use for human activities, fisheries, tourism and agriculture such as the flower business. The higher erosion rates which cause increasing sedimentation of the lake also cause greater inputs of nutrients and pollutants to the lake. These nutrients and pollutants threaten the ecological state of the lake, i.e. by an increased nutrient concentration. A possible solution to decrease the siltation of the lake is to rehabilitate the former Northern Swamp, a former wetland of about 4 km² north of Lake Naivasha to retain sediments and prevent them from ending up in the lake. In 2009, Marula Estates, a large commercialized agricultural landholding bordering the former Northern Swamp, on its own initiative performed a study on the current state of the wetland and created a plan to rehabilitate the former Northern Swamp. The first phase of this plan was implemented already in 2009 and because the results are satisfying, the second phase of the project, which consists of the construction of a dam to buffer water from the Malewa River, will be implemented. The implementation of the second phase however is currently on hold due to the high lake water level, which needs to drop sufficiently to provide access for machinery to execute the necessary works. This forced break gives the opportunity to review the design from a Water Engineering perspective, which led to the research objective of this study: “To evaluate the functioning of two alternative rehabilitation alternatives, with in particular the sediment trapping efficacy, by modeling the sediment transport processes for various Malewa River discharges using a one-dimensional modeling approach”. The first rehabilitation alternative is a wetland through which the water flows from the Malewa River via a spillway channel and wetland into Lake Naivasha, based on the design as presented by Marula Estates (2013). The second alternative consists of the same spillway channel to divert the water from the Malewa River into a meandering channel flowing into Lake Naivasha. To achieve this research objective, a literature study and field work, in May – June 2013, are done to get insight in the former Northern Swamp and the rehabilitation plan. To model the sediment transport processes an empirical formula that relates sediment load and discharge is used together with an integrated software package for river management called SOBEK. With this model it is possible to make an estimation of the amounts of sediments entering through the inlet construction, and it is possible to get insight in the sediment transport processes within the two rehabilitation alternatives. The Wetland alternative turns out to be the best alternative when considering sediment trapping efficacy. For the year 2010, when taking into account the maximum discharge entering the wetland of 25 m³/s to prevent flooding of the spillway channel, the sediment inflow into Lake Naivasha could have been reduced with 15%. Due to the current wetland design specifications, based on discharge data from 1960 till 2010, on average only 1.25% of the time water can be diverted from the Malewa River through the spillway channel into the wetland. For 2010 however, water could have been diverted for almost 7% of the time and therefore, the reduction in sediment inflow into Lake Naivasha is likely to be lower for other years. Also, due to the limited possibility of utilization of the wetland, rehabilitation of the former Northern Swamp is going to be difficult.
  • Project KEN/74/023 Offshore Trawling Survey, Work Report no. 6: Line fishing during the survey period 1979–1981.

    Government of Kenya; UNDP; FAO (Food and Agriculturel Organization, 1981)
    With four hand operated snapper reels have been fished on, for R/V UJUZI, non trawlable grounds mainly on the North Kenya Bank. The catches have been analysed by region, season and depth and compared with handline oatches. Average catch rates on the North Kenya Bank ranged from 2-3-6.4 kgs/reel-hour, highest in the depth range 16-75 meters during the south-east monsoon period. In other areas the average catch rates were below 1 kg/reel-hour. In the north-east monsoon period the family Lutjanidae formed the bulk of the catches, with two species Lutjanus sanguineus and Pristipomoides (~ clearly depth restricted. In the south-east monsoon period the family Serranidae dominated with its speoies EPinephlus tauvina especially in the shallower waters.
  • Impacts of Tree Harvesting on the Carbon Balance and Functioning in Mangrove Forests.

    Lang'at, J.K.S. (Edinburgh Napier University, 2013)
    The importance of mangrove forests to the livelihoods of the local communities as well as to the ecological functioning of coastal ecosystems has been widely recognised. However, mangrove forests are at a high risk of being degraded and lost due to rapid growth of human populations and the economic pressures subjected to the coastal ecosystems. The implications of mangrove deforestation and degradation on the ecological functioning of these systems are far reaching and hence need to be investigated. This study experimentally explored the impacts of small scale cutting of mangroves on the functioning of the ecosystem. Secondly, it aimed to estimate belowground productivity of mangroves, as well as relating aboveground biomass production to belowground root production. Chapter one gives an over-view of the role of mangroves in carbon sequestration. Particular emphasis is given on the roles of mangroves in climate change mitigation and adaptation, as efficient carbon sinks, coastal stabilization and protection. The controls of carbon fluxes in mangrove forests as well as the impacts of deforestation on mangrove ecosystem functioning are explored. The patterns of mangrove productivity are also discussed. Chapter two experimentally explores the implications of small scale cutting on carbon fluxes in mangrove forests. The findings indicate that mangrove cutting can enhance additional C emissions of 9.8 ± 7.1 tCO2 ha-1 yr-1. Similarly, small scale cutting can also induce subsidence at the rate of -32 mm yr-1 within 2 years of cutting. Chapter three discusses the impacts of tree canopy removal on the biotic attributes of the mangrove ecosystems. The results show that removal of all vegetation can drastically affect the ability of the forest to rejuvenate. Furthermore, canopy removal significantly influences species composition of macrofaunal communities, whereby, gap-preferring species would colonize and dominate open areas created by canopy removal. Chapter four gives an insight on the patterns of mangrove forest productivity on a local scale. The findings indicate that even at a local level variation in forest productivity exists, probably due to micro topographic differences and soil factors. The results also confirm the high investment in belowground components. There also exist a possibility of significant relationship between above- and belowground biomass productivity. It is also shown that below-to-aboveground productivity ratios follow similar patterns to below-to-aboveground biomass ratios. Chapter five provides general conclusions of the preceding chapters putting the findings in line with the current trends in mangrove forest decline. The strategies of reversing mangrove decline are also suggested, including the financial initiatives such as Payment for Ecosystem Services (PES) schemes through strategies such as Reducing Emissions for Deforestation Degradation (REDD+). Finally, a number of recommendations are given including sound management options and further issues arising from this study.
  • Lake Victoria’s Nile Perch Fish Cluster: Institutions, Politics and Joint Action.

    Mitullah, W. (Institute of Development Studies, University of Nairobi, 2000)
    The collective efficiency model contends that joint action is essential for coping with new challenges. This paper discusses how enterprises in the Lake Victoria fish cluster operate, interact and address common challenges facing the industry. It suggests that the lack of effective institutions and the existing power relations explain the inability of the cluster to respond effectively to recent crises. Both the Co-operative Society and the Fisheries Department are weak, whereas the existing welfare based associations merely exploit social capital in sub-ethnic groups. These groupings have not transcended welfare concerns into the economic realm, and their potential for taking strategic joint action is limited. The cluster’s strongest joint action has been vertical, between one successful trader and one Industrial Fish Processor (IFP). This action saved the cluster from imminent collapse, but it did not result in the creation of institutions or organisations capable of dealing with other problems. The results uphold the collective efficiency model in the sense that they underscore the need for joint action in the face of new challenges. The findings also call for extension of the model to consider more explicitly the institutional framework that appears necessary for effective joint action to take place.
  • Trends in the distribution of macroalgae in a bleached Kenyan reef ecosystem.

    Uku, J.; Ndirangu, S.; Muthama, C. (CORDIO-SAREC, Stockholm University, 2002)
    In May 1999, two sites were selected within the Mombasa Marine Park and Reserve for the study of macroalgal succession due to bleaching. One of the sites was Starfish, which lies within the Mombasa Marine Park and is protected from fishing and the other site was Ras Iwatine, which lies in the Reserve area and is Subjected to fishing activities. The study revealed that the Starfish site had a significantly higher hard coral cover, which did not change over the study period. A comparison of the density of macroalgae revealed that a higher proportion of the substrate in Ras Iwatine was dominated by macroalgae. Settlement tiles, used to study algal recruitment, indicated that the succession process in the Starfish site passes through more stages compared to the Ras Iwatine site. This succession process suggested the influence of grazers in Starfish and their importance in maintaining a lower cover of macroalgae in this site.
  • IOC/LUC/KMFRI Workshop on RECOSCIX/WIO in the year 2000 and beyond (and training course for librarians), Kenya Marine and Fisheries Research Institute, Mombasa, Kenya, 12-17 April 1999

    Description The Workshop was held in order to provide an opportunity to evaluate the activities of the project RECOSCIX-WIO, launched in February 1989 by IOC, and also to redefine the priorities of the project. Details are given of the report of the RECOSCIX-WIO Regional Despatch Centre and the reports of the various cooperating institutions are included as annexes to the publication -- National Museums of Kenya (NMK) Library, Institut Halieutique et des Sciences Marines, Albion Fisheries Research Centre, Instituto Nacional de Hidrografia e Navegacao (INAHINA), Seychelles Fishing Authority, Institute of Marine Sciences, RECOSCIX-CEA Report, International Association of Aquatic and Marine Science Libraries and Information Centres (IAMSLIC) Report, and ODINAFRICA-II. Four Working Groups were held, covering the following themes: 1) Review of project objectives and structure; 2) Services and products -- new technologies that can be used to improve them; 3) Capacity building -- equipment and personnel available in CIs and RDC and what needs to be done to improve on them; and, 4) WIOLIB structure. It was concluded that the original objectives of RECOSCIX-WIO are still valid, and a list is given of recommended actions to be implemented.
  • Towards Integrated Management and Sustainable Development of Kenya's Coast: Findings and Recommendations for an Action Strategy in the Nyali-Bamburi-Shanzu Area.

    Coastal Development Authority; Mombasa Municipal Council; Kenya Marine & Fisheries Research Institute; Kenya Association of Hotelkeepers and Caterers; Kenya Wildlife Service (1996-07)
    This document – an integrated Coastal Area Management (ICAM) Action strategy for the Nyali-Bamaburi-Shanzu area is the outcome of a participatory process to reach a broad consensus on how to address these critical coastal management issues at the site, as well as gain experience in ICAM for application to other areas in Kenya. Foe each issue, Findings of fact are presented. These provide background information about the topic, focusing on its significance and the causes and consequences of the problem. Management objectives and implementation strategies are set forth.