Recent Submissions

  • The African Science-base for Coastal Adaptation: a continental approach. A report to the African Union Commission (AUC) at the United Nations Climate Change Conference in Copenhagen (7-18 December 2009).

    Abuodha, P. (Intergovernmental Oceanographic CommissionParis, France, 2009)
    A report to the African Union Commission (AUC) at the United Nations Climate Change Conference in Copenhagen (7-18 December 2009). “In Gambia ... In 1998, the high water mark (HWM) was 50 m from the new Banjul-Serekunda Highway; in 2003 the HWM was only about 15 m from the highway” (Adaptation to Coastal Climate Change Project, ACCC, 2006a). Between Cape Point and the Banjul dockyard and the area between the Palm Grove Hotel and the Muslim cemetery erosion rates of between 15 and 20 m were recorded from 1964 to 1982...” In one brief paragraph we see the relentless attacks of rising sea levels and growing storm surges on one coastline, threatening four significant elements of society – transport, trade, tourism and tradition.
  • KenSea – tsunami damage modelling for coastal areas of Kenya

    Tychsen, J.; Geertz-Hansen, Ole; Schjøth, Frands (2008)
    The tsunami modelling is based on the assumption that the height of a future tsunami wave would be comparable with the one that reached the coastal area of Kenya in December 2004. Based on the regional geology of the Indian Ocean, it appears that the epicentre for a possible future earthquake that could lead to a new tsunami would most likely be situated in the eastern part of the ocean. Furthermore, based on a seismological assessment it has been estimated that the largest tsunami that can be expected to reach eastern Africa would have a 50% larger amplitude than the 2004 tsunami.
  • Kenya Tuna Fisheries Development And Management Strategy 2013-2018.

    Republic of Kenya, Ministry of Agriculture, Livestock and Fisheries (Republic of Kenya, Ministry of Agriculture, Livestock and FisheriesKenya, 2013)
    The National Tuna Management and Development strategy provides a roadmap for the sustainable development of the Kenya's tuna fisheries resources occurring in the Exclusive Economic Zone (EEZ) and ensuring an efficient tuna fisheries value chain. The overall goal of the strategy is to transit tuna fisheries from artisanal-based fisheries to modern commercially oriented coastal and oceanic fisheries and accelerate economic growth of the marine fisheries with direct positive impacts to employment, wealth creation, improved incomes and foreign exchange earnings. Chapter two reviews the current situation of tuna fisheries from a global, regional and national perspective regarding the status of tuna stocks, exploitation and impacts on marine ecosystems, the obtaining trade regimes and value chain activities and the prevailing tuna fisheries governance system. The strategy identifies four main strategic issues namely; Unsustainable utilization of marine resources; Low economic benefits accruing from tuna fisheries to the national economy; Inadequate tuna fisheries governance and General cross-cutting issues including gender issues, and HIV and Aids. To address the strategic issues, four strategic objectives are prioritized for implementation. First, the maintenance of tuna stocks at sustainable levels and minimizing negative fishing impacts on the marine ecosystem. Secondly, transformation of tuna fisheries from artisanal fisheries to a modern commercially oriented coastal and oceanic fisheries and developing an effective tuna fisheries governance system that takes into account national, regional and international requirements and addressing the impact of HIV/ AIDS pandemic and gender issues in tuna fisheries. A detailed implementation matrix for each strategic objective with the relevant activities is outlined in chapter five. Mechanisms for measuring progress during implementation and financing arrangements are highlighted in Chapter six.
  • The Kenya Pearl Oysters.

    Kimani, E.N.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    This report provides a brief description of the pearl shell trade and the occurrence of pearl oyster species between Shimoni and Malindi, in Kenya and the population densities and structure of the most important commercial species, Pinctada margaritifera L from preliminary data collected in 1998 and 1999. Pinctada margaritifera L, and Pteria chinensis Leach, were widely distributed in the study area. The species, Pteria penguin Roding, only occurred in the Wasini Channel in Shimoni. P.margaritifera population density was highest in shallow sites dominated by seagrass within Gazi Bay. Pooled population density data showed that the oysters were more abundant in shallow water, less than 5 m depth. Most of the individuals in the samples were between 10 to 60 mm in size. The largest individual was 123 mm and was collected from a sheltered reef in Shimoni. There were more males than females and the mean size of females was larger than that of males. The size at first maturity of males was smaller than that of females. The proportion of males was higher in small-size class oysters and lower in large-size classes. These reproductive adaptations appear to be a strategy to sustain the oyster population.
  • Strategies Used by Local Fishers to Ensure access to and Control over Scarce resources in Galu and the Wider Implications for Marine Resource Management.

    King, A.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    An analysis of livelhoods and production systems in the community of Biga, Galu sub-location, showed that there was a high degree of socioeconomic differentiation within the community. Differences related to production methods. These included different fishing methods, land use activities, economic activities or different combinations of the above. The processes by which fishers tackled problems of resource access and control were investigated for three situations: the attempted implementation of the Diani-Chale marine reserve; the grabbing of Trust land earmarked for fisheries community use at Mwaepe; the conflict between local Digo fishers and migrant Wapemba fishers. Using social network analysis the importance of different actors (groups, individuals and organizations) in solving the fishers' problems was determined. The results showed that some unexpected actors, such as those without natural resource management remits, were very important in the process. The social network analysis also showed that although people's resource access and control are shaped by many interacting institutions, adhoc processes, where people simply seek whatever path is necessary to solve their problems, also play an important role. The wider implications for marine resource management relate to creating socio-political and institutional environments that enable problems to be solved. Discussion includes the need to have a better understanding of what is going on at the local level, both in terms of livelihoods and institutional arrangements. It also questions the validity and effectiveness of current over structured approaches to management that impinge on peoples' ability to safeguard their food security.
  • Shrimp Trawling in Ungwana Bay A Threat to Fishery Resources.

    Fulanda, B.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    This paper examines the landings of three trawlers fishing the Ungwana Bay (Kenya) over a seven day period totalling about 200 hrs fishing time. A critical analysis is made of the catch and its composition in terms of marketable catch (target species and commercial fish) and bycatch (non-commercial, juveniles and debris). Prawns made up 13.7% of the catch while commercial fish amounted to 14.4% of the total. The remainder (71.9%) comprised of bycatch. Further breakdown showed that non-commercial fish made up the bulk of the by-catch with 42.9%. This group included Branchyura, Apogonidae, Leiognathidae, Squillidae and Gobiidae families. Juveniles accounted for 23.6% of the by-catch. The latter consisted for almost two-thirds of juveniles of commercial fish among which Ariidae were the commonest. Other families included Atherinidae and Carangidae. In the shallow 'Kipini' area, trawling does considerable damage to the benthic fauna and flora. The trawling attracts a large population of piscivorous birds creating artificial and unstable food webs. A Turtle Excluder Device (Anthony Weedless) was used on one of the trawlers but it appeared to result in lower catch of commercial fish allowing only small species and undersized fish into the cod end. It is concluded that the trawlers pose a threat to both the Ungwana fishery and other marine resources.
  • Water Quality and Species Diversity of Intertidal Macroalgae.

    Mwayuli, G.A.; Manohar, S.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    Spatial and temporal changes in species diversity, abundance and composition of macroalgae in the intertidal zones at Kanamai and Da Gama Point along the Kenyan north coast were studied from March to September 1999 to investigate their relationship with water quality. A total of 63 species of macroalgae were collected, 23 belong to Chlorophyta, 23 to Rhodophyta and 17 to phaeophyta. There was an increase in the coliform number per 100ml of water from 60 to >1600 and from 90 to 1600 at Kanamai and Da Gama Point respectively. Phosphate levels showed an increase from 0.56 to 1.025 and from 1.420 to 1.750 mu g atoms P/litre for Kanamai and Da Gama Point respectively. Ammonia also incleased from 1.350 to 1.540 and from 3.800 to 4.250 mu g atom N/litre for Kanamai and Da Gama Point respectively. At Da Gama point there was a tendency towards dominance by fewer species. Pollution by sewage and elevated nutrient levels is evident. Kanamai is less nutrient-rich resulting in the higher species diversity, composition and eveness in distribution.
  • The Impact of Human Activities on Epibenthic Bivalve Communities.

    Boera, N.P.; Okeyo-Owuor, J.B.; Wangila, B.C.C.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    A total of 17 bivalve species belonging to 135 families were collected and identified in Malindi, Mombasa Marine National Parks, and Kanamai from Oct.'97 to Mar.'98. Bivalve fauna showed densities 2/m super(2), and low diversity. Modiolus auriculatus and Pinna muricata were the most represented. There was a significant difference in species diversity between Malindi and Mombasa reef flats at p>0.10. Shallow lagoons had very low density and diversity as compared to sea grass and reef flat zones. This was attributed to the high deposits of shell, coral, and sand. Swimming, goggling/scuba diving, walking/trampling and turning of rocks were identified as the main forms human activities causing disturbance to the bivalves. Frequencies of occurrence of these activities varied in the three areas with Kanamai exhibiting the highest. Trampling had the most notable impact and was used to show the impact of human activities on the most vulnerable species. Results show that the distribution of bivalve fauna in the protected and unprotected areas is density independent and is not only influenced by human activities and management strategy but rather by other biological and environmental factors such as substrate type, tide range and wave activity. Human activities however affect those bivalves with fragile shells such as Pinna muricata, through trampling resulting in injury and/or death. Presence of man affects the routine activities of the others such as Tellina flavum, Anadara antiquata, Tridacna squamosa and Codakia punctata. Therefore spreading out of human activities within the marine parks is recommended to reduce their impacts. These activities should be spread out into the reserves and unprotected areas.
  • Macrofaunal Assemblages of Littoral Seagrass Communities.

    Muthama, C.M.; Uku, J.N.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    A comparison of macrofauna found in vegetated seagrass areas and unvegetated areas was undertaken in Nyali Beach, Kenya. This study was aimed at establishing the importance of seagrasses to the Kenyan marine environment. Sampling was conducted during the N.E. and S.E. monsoon periods. The trends show that the vegetated areas had a slightly higher abundance of macrofauna compared to the unvegetated areas. Furthermore, the areas with a mixed vegetation cover supported a higher number of macrofauna during the N.E monsoon. The overall abundance of macrofauna was also found to be higher during the N.E. monsoon period. This paper discusses the importance of different seagrasses in the maintenance of coastal biodiversity.
  • Coastal Erosion at Mombasa Beaches Hydrodynamic and Morphological Interactions.

    Mwakumanya, M.A.; Tole, M.P.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    Complex interactions of various natural processes together with anthropogenic activities on the beaches have encouraged coastal erosion along the Kenyan coast. Inadequate information on site-specific hydrodynamic and morphological and morphological interactions on the shores has encouraged mitigation measures which are ineffective and expensive to implement. Hydrodynamic and morphological parameters were measured both in field and laboratory. Hydrodynamic variables contributed significantly to the morphological variability which consequently accelerated beach erosion and shoreline instability. Nyali beach which was dominantly fine sand (0 2.62-2.83), moderately well sorted (0 0.564.75) and negatively skewed was characterised by low energy surging waves with high swash and low backwash velocity at high periodicity. Sediment composition was mainly quartz. Bamburi beach was of medium sized calcareous sand (0 2.79-1.84), moderately to poorly sorted sand (O 1.34-0.87) and negatively skewed. Hydrodynamic conditions were of high energy pluging waves and high backwash velocities. Wave energy contributed about 74.2% to the slope changes and about 83.0% to sediment distribution on the beaches. Generally steep shores of coarse sediments showed active erosion activities with a rate of retreat of about 0.15m/month to 0.22 m/month of the shoreline. It is recommended that measures be taken to dissipate wave energy before wave break on the shoreline and to develop effective legislation to protect the shoreline for sustainable planning utilisation and management of the marine ecosystem.
  • Solid Waste Management in Mombasa District.

    Maende, S.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    Aspects of solid waste management in Mombasa District are analysed. The findings are from a survey conducted between November 1998 and February 1999, that covered educational Institutions, supermarkets, hospitals, hotels and restaurants, markets, recreational parks, industries, waste collectors, residential areas, and waste re-users and recyclers - all drawn from Mombasa District. The paper outlines issues of waste generation, handling, transportation, storage and disposal special emphasis on waste re-use and recycling. Brief recommendations are included.
  • Solid Waste Pollution Loads In Beach Hotels on the Kenyan South Coast.

    Muthini, M.; Tole, M.P.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    During the high tourist season between September 1996 and February l997, solid waste types and quantities from six popular beach hotels in Mombasa and Diani were determined. The factors and processes that affect solid waste management in the region were examined and baseline data on quantities of waste generated in coast hotels are provided. The mean percapita waste generation rate was found to be 1.90 kg/person/day and the relative proportions by weight of the respective waste categories were: paper 3.5%, plastics 3.3%, tins 1.7%, glass 4.5% food waste 79.1%, cartons 2.0%, and residual waste 6.0%. The rates of generation of waste components were also calculated. The annual waste load was found to be 362 tons for Jadini Beach Hotel and Africana Sea Lodge; 200 tons for Leopard Beach Hotel; 159 tons for Diani Sea lodge; 192 tons for Severin Sea Lodge and 150 tons for Mombasa Beach Hotel. Limited recycling, re-use and composting practices were undertaken by some of the hotels such as Mombasa Beach Hotel, Severin Sea Lodge and Dianl Sea Lodge. Tins were re-used for planting tree seedlings and flowers. Glass waste and cartons were collected by dealers for recycling. Food waste was used to feed pigs. The results of the study make it possible to develop a feasible waste management concept for the hotels. There is potential for recycling re-use and composting of the waste generated. It is recommended that hotels effectively separate waste at source to ensure high quality waste components for further processing. This will help to reduce the costs of waste disposal, minimise health risks and improve the quality of the environment.
  • The Effect of a Marine Protected Area and the Exclusion of Beach Seines on Coral Reef Fisheries.

    Mangi, S.; McClanahan, T.R.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    Fish landing data from adjacent the Mombasa Marine National Park (MNP) and seven sites in Diani (Kenya) were studied from 1995 to 1999 to determine the influence of the park and restrictions of beach seines on fisheries catches. Data were based on sampling for 10 days per month, where fish were separated into the major families, the wet weights estimated by a spring balance, and data analysed based on gear, numbers of fishers, and the area from which the fish were caught. In the case of the Mombasa marine reserve, the beach seine exclusion was done nearly simultaneously with a reduction in the size of the Marine Protected Area. These two factors combined resulted in increased fish catches on a per area and fisher basis. It was, however, difficult to distinguish the effects of the two changes, but the initial pulse (< 6 months) in catch is largely due to opening a previously unfished area to fishing. After the large initial increase in the catch there was a decline over time, but catches were still above those before the management changes. In Diani the two landings that restricted beach seines for over 20 years had the highest per fisher catches, being 13% greater than sites with beach seines, while those that still adopt beach seines had the lowest catches (ANOVA, F = 4.5). Data shows a progressive decline in per man catches in all the sites irrespective of the management in place or the exclusion of the beach seines. Nevertheless, the marine reserve had the highest catch per area (5.5 kg/ha) despite having the highest number of fishers per area basis (7~c2 fishers/ha/month). There were no strong seasonal patterns from time series plots for the catch statistics. We show that parrotfishes (Scaridae), rabbitfishes (Siganidae), scavengers (Lethrinidae and Lutjanidae) and octopuses (Octopo-didae)are the major groups dominating these fisheries.
  • Awareness of Resource Degradation among Artisanal Fishers in Kilifi and Lamu.

    Tunje, J.G.; Hoorweg, Jan; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    The study was carried out in Kilifi (including Malindi) and Lamu Districts of Kenya, focusing on the activities of artisanal fishermen. The fishing methods that the fishermen use and the extent they contribute to coral reef degradation were the major study objective. The fishing methods used, factors for their choice, and their perceived impact on coral reefs were investigated. Indigenous environmental conservation efforts, fishermen's alternative source of income, and attitudes towards environmental conservation were also examined. Fishermen mainly use the gear they have experience with and gear that brings them high catches. They did not consider the environmental impacts of the gear they used. The results also revealed that there were few signs of indigenous marine conservation in this part of the coast. Half of the fishermen interviewed observed certain cultural restrictions relating to personal safety at work, good hygiene and fish handling. The other half did not. Finally, local fishermen are willing to initiate and participate in programmes of marine environmental conservation aimed at the fishery resource as long as it enables them to improve their incomes.
  • Food Security Benefits of the Kisite Marine National Park for the Surrounding Fishing Communities.

    Malleret-King, D.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    This paper aims at investigating if and how Marine Protected Areas (MPA) benefit the surrounding communities. The food security status of five fishing communities surrounding the Kisite Marine National Park on the south coast of Kenya was examined. The underlying assumption was that if MPAs benefit the surrounding fisheries, it would show in the socio-economic status of the fishing communities. Effects of the presence of the park were detected in several ways. First, it was found that households depending for their livelihoods on tourism around the parks were more food secure than the others. Secondly, it was established that the economic structure of the communities was affected by the distance of the communities from the main tour operators linked to the park. Finally, the households fishing nearer the protected reefs were found to be more food secure than others. However, these benefits of the park are constrained by the distance of the communities from the park.
  • Environmental Factors in Coral Bleaching: The 1997/8 El Nino in Kenya.

    Mdodo, R.M.; Tole, M.P.; Obura, D.; Muthiga, N.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    Elevated sea water temperature in March and April 1998 caused by the El Nino Southern oscillation caused mass coral bleaching along the Kenyan coast. Over 90% bleaching and mortality was recorded in the region. Chlorophyll-a concentration ranged between 0.002-0.284 mg/cm super(2) for bleached corals and 0.176-0.795mg/cm super(2) for normal corals. Zooxanthellae density ranged between 0.7x10 super(6)-5xl0 super(6) per cm super(2) for normal corals and 0.02x10 super(6)-0.2x10 super(6) per cm super(2) for bleached coral (total loss of zooxanthellae and pigment was recorded in a few coral fragments).
  • Disturbance, Recovery and Restoration of Kenyan Coral Reefs.

    McClanahan, T.R.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    Evidence for the degradation of Kenyan coral reefs is abundant but the means to restore and manage them is less well understood. Degradation studies show that there are often two terminal states of coral reefs: one where the reef is dominated by large fleshy algae and the second by abundant sea urchins. Summaries of studies are presented where sea urchins and fleshy algae were reduced in order to determine the effect of algal and sea urchin dominance on coral reefs as well as the effect of elimination of fishing on one coral reef. Studies indicate that reducing coral reef plant and animal pests work best if done in areas where fishing is reduced. Reduction of fishing in one coral reef produced a number of predicted changes in the reefs, including increased fish and coral cover and reduced sea urchin and algal turf abundance. There are few options to restoring reefs that will not require reduced fishing effort. Many reefs presently have low coral cover due to the coral bleaching and mortality in March 1998, so there is a need to increase coral reef restoration activities.
  • Antiprotozoal Activities of Lyngbya MajuscuIa, Abudefduf Sexfasciatus and Thallassodendron Ciliatum.

    Dzeha, T.M.; Halevy, S.M.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    Methanol (MeOH) extracts of the pan-tropic marine Cyanophyte Lyngbya majuscula, Thallassodendron ciliatum (sea grass) and gill extracts of the Striptail damsel Abudefduf sexfasciatus were examined for in-vitro antiprotozoal activity against Ochromonas danica cultured in hemin enriched media at room temperature using a 50% serial dilution technique. Respiratory inhibition at the 660 nm wavelength was shown to be proportional to the concentration of the extracts with R2 values of 0.992, 0.996 and 0,542 for L. majuscula,Asexfasciatus and T. ciliatum respectively. T. ciliatum exhibited lower inhibition potential where as Asexfasciatus had the highest. Malnourished O. danica at the elevated dilutions of 75% were especially susceptible. In addition to the anticipated antibiosis, rhodamine toxicity and brine shrimp anemia bioassay suggest a role by haemolysin toxins of L. majuscula and A.sexfasciatus in the 24 hour respiratory inhibition process.
  • Die-Back in Sonneratia Alba in Kenyan Mangroves is due to Attack by a Cerambycid Beetle and a Metabellid Moth.

    Gordon, I.; Maes, K.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    Extensive die-back in the pioneer mngrove tree, Sonneratia Alba along the Kenyan Coast was investigated. It was caused by a cerambycid beetle (Bottegia spinipennis) and a metabellid moth (Salagena obsolescens). The beetle attacked small branches, laying its eggs singly, while the moth attacked large branches, laying its eggs in batches. The beetle was found at two sites, Mida Creek in the north and Gazi in the south. The moth was found at Gazi. Three parasitoids belonging to two species of Echthromorpha were reared from the beetle larvae. Some basic observations on the life histories of the two species are reported. Both species are Afrotropical in their distribution.
  • Biodiversity and the Kaya Forests.

    Luke, W.R.Q.; Githitho, A.N.; Hoorweg, Jan; Muthiga, Nyawira (African Studies CentreLeiden, Netherlands, 2003)
    This paper contains a review of the work of the Coastal Forest Conservation Unit in protecting the traditional kayas with their large biodiversity. Ongoing botanical research as well as research of a wider nature is listed and activities such as afield herbarium and an indigenous plant nursery are briefly described. A list of selected references on coastal flora is attached.

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