South Coast Of Kenya Research Articles

Low Rate of Asymptomatic Dengue Infection Detected in Coastal Kenya Using Pooled Polymerase Chain Reaction Testing.

Asymptomatic dengue virus (DENV) infections have important public health implications but are challenging to identify. We performed a cross-sectional study of reverse transcription quantitative polymerase chain reaction on pooled sera of asymptomatic individuals from the south coast of Kenya at two time periods to identify cases of asymptomatic viremia. Among 2,460 samples tested in pools of 9 or 10, we found only one positive case (0.04% incidence). Although pooling of samples has the potential to be a cost-effective and time-efficient method for asymptomatic DENV detection, mass cross-sectional pooled testing may not provide accurate data on rates of asymptomatic infection, likely owing to a decrease in the sensitivity with pooling of samples, a short period of viremia, or testing in the absence of an outbreak.

Exploring factors associated with Trichuris trichiura infection in school children in a high-transmission setting in Kenya

ObjectivesKenya has implemented a national school-based deworming program, which has led to substantial decline in the prevalence of soil-transmitted helminths (STHs), although some pockets of infections remain. To effectively design an STH control program that leads to significant reductions of Trichuris trichiura, there is a need to understand the drivers of persistent infection despite ongoing treatment programs. MethodsThis study was conducted between July and September 2019 at the south coast of Kenya, using a two-stage sampling design. First, a school-based cross-sectional survey was conducted in 2265 randomly selected school children from selected schools in areas known to be endemic for T. trichiura. After this, we conducted a nested case-control study wherein all children positive for T. trichiura (142) were matched to 148 negative controls based on age and village. A household survey was then conducted with all household members of cases and controls. In addition, a subsample of 116 children found to be infected with T. trichiura were followed up to assess the efficacy of albendazole at day 21 post-treatment. The predictors of presence of T. trichiura were investigated through multilevel logistic regression, considering clustering of infection. ResultsOverall, 34.4% of the children were infected with at least one STH species; T. trichiura was the most common (28.3%), 89.1% of those with T. trichiura had light-intensity infections. The prevalence of T. trichiura was significantly higher in male children and was positively associated with younger age and number of people infected with T. trichiura in a household. The parasitological cure rate and egg reduction rate of T. trichiura were 35% and 51%, respectively. Other STHs identified were hookworm (9.6%) and Ascaris lumbricoides (5.7%). ConclusionsT. trichiura remains a significant public health challenge in the study area with albendazole treatment efficacy against the parasite, remaining lower than the World Health Organization–recommended thresholds. Because of the observed focal transmission of T. trichiura in the current area, control efforts tailored to local conditions and targeting lower implementation units should be used to achieve optimal results on transmission.

A peek into the population genetics of white teatfish (Holothuria fuscogilva) of Kenya's south coast.

The white teatfish, Holothuria fuscogilva, is widely distributed in coastal areas, including waters around coral reefs and seagrasses in the Indo-Pacific. In Kenya, the species is distributed in shallow reefs with higher landings reported from the Vanga-Shimoni-Gazi seascape on the Kenyan south coast. Despite its high exploitation for export and its vulnerable and endangered statuses under IUCN and CITES respectively, Kenya's H. fuscogilva populations and how they may have been impacted by the fishing pressure have not been studied. We estimated the genetic diversity and structure of H. fuscogilva population conveniently sampled from three sites in Kenyan south coast using the mitochondrial cytochrome oxidase subunit I (COI) gene sequences. We recorded 30 haplotypes with 43 polymorphic sites across the population. Furthermore, we estimated an overall high haplotype diversity and low nucleotide diversity of estimates of h = 0.970 ± 0.013 and π = 0.010 ± 0.001 respectively. These preliminary findings suggest several population outcomes, among them a fit population, which require confirming with more comprehensive study to inform strategies for the sustainable exploitation and management of the species.

Assessment of Heavy Metal Pollution in Soil and Associated Risks in the Environs Adjacent to a Heavy Mineral Sand Mine on the South Coast of Kenya

Assessment of Heavy Metal Pollution in Soil and Associated Risks in the Environs Adjacent to a Heavy Mineral Sand Mine on the South Coast of Kenya

Conservation and Preservation of Immovable Heritage from Below: Local Community Involvement in the Management of Shimoni Caves in the South Coast of Kenya

Conservation and Preservation of Immovable Heritage from Below: Local Community Involvement in the Management of Shimoni Caves in the South Coast of Kenya

Retained fish catches of artisanal fishers is dependent on fishing area, season and fishing gear type: A case study from the south coast of Kenya

The artisanal fishery is one of the sources of livelihood along the Kenya coast. Catches of retained fish of artisanal fishers between two fishing areas on the south coast of Kenya were compared. Artisanal fishers usually retain a portion of their daily catch which is reserved for family consumption while the rest is traded for cash to meet other family needs. This study hypothesized that retained fish catches were influenced by fishing area, fishing gear type and season. Daily fish landings and retained fish catches among artisanal fishers were monitored between August 2020 to July 2021 covering the South East Monsoon (SEM) and North East Monsoon (NEM) in Msambweni and Vanga fishing areas. A total of 60 fishers (30 for each area) were randomly selected and their retained catch monitored on a daily basis. The overall total fish landings were 23.3 tons and 210 tons in Msambweni and Vanga, respectively. The mean catch rate at Msambweni was 3.3 ± 0.12 kg.fisher-1day-1 in the NEM season and 2.2 ± 0.09 kg.fisher-1day-1 in the SEM season. Fish catch rates in Vanga was 8.5 ± 0.28 kg.fisher-1day-1 in the NEM season and 7.9 ± 0.29 kg.fisher-1day-1 in the SEM season. A total of 0.98 tons (only 4.2 %) of fish was retained versus 22.32 tons (95.8 %) not retained by the artisanal fishers in Msambweni, while in Vanga a total of 1.64 tons (only 0.78 %) was retained versus 208.36 tons (99.22 %) not retained. Retained fish catch varied significantly with season and type of fishing gear used (p < 0.05). Among the retained species in Msambweni, Siganus sutor made the highest contribution (53 %), followed by Lethrinus mahsena, (5.08 %). The species Euthynnus affinis and Sphyraena obtusata were mostly retained in Vanga with a contribution of 10.4 % and 10.2 %, respectively. The same retained fish species represented the most abundant species in the overall fish landings, however sizes were significantly smaller than those not retained by fishers (p < 0.05). Results of non-Metric Multidimensional Scaling (nMDS) ordination showed differences in species composition between fishing areas, seasons and fishing gear types with implication on fishers’ retained catches.

Tropical marine faunal hazard knowledge, incidents and associated health burden among seascape users at the Kenyan coastline

Tropical shorelines, acclaimed as serene destinations and supporting local seascape user livelihoods, also harbour dangerous marine organisms, causing injury, envenomation and poisoning, that frequently challenge existing species and curative interventions. Documentation of indigenous knowledge on harmful marine biota is critical to develop cost-effective integrated management interventions. Dedicated cross-section interviews among indigenous seascape users in Mtwapa at the north and Gazi at the south coast of Kenya, elicited data on demographics and injury, envenomation and poisoning, as well as financial burden. Responses from 100 respondents, dominated by adult, Mijikenda males, participating in fishery (boat, foot) and beach services (trade, beach boys), were analysed. Over 24 dangerous marine fauna; causing injury (shark, urchin), envenomation (stingray, lionfish & stonefish) and poisoning (puffers), were documented. Over 39 biohazard incidents per year, mostly by urchin, stingray, stonefish and lionfish with an estimated yearly intervention cost of 151$, and corresponding burden of 18% of earnings, occurred. Biohazard events differed significantly (P < 0.01) between incident and livelihood. Injury prevalence (74 yr−1), cost (275$.yr−1) and burden (15%), were significantly (P < 0.001) higher than envenomation, while poisoning was rare. Foot fisher injury (66%) and envenomation (15%) burden, were significantly higher than other livelihoods, attributed to unprotected intertidal wading, inexperience and low incomes, leading to increased expenditure. Delivery of universal healthcare targets to coastal communities, should incorporate biohazard management, to reduce health burden.

Effect of selected environmental factors on microalgae diversity and abundance in Gazi Bay, south coast Kenya

Microalgal community structure of Gazi Bay, Kenya and association with environmental factors was studied between February, June 2019 and October 2020. Non-Metric Multidimensional Scaling (NMDS) and the Rarefaction curves were used for the analysis of community structure; while Principal Component Analysis (PCA) was used to determine correlation between environmental factors with abundance and species diversity of microalgae. A total of 79 microalgae species belonging to 10 classes were recorded, with diatoms dominating in all the sampling sites. The three most abundant species of microalgae observed were Scripssiela sp, Peridinium quinqeucorne, and Striatella sp. There was temporal and spatial distribution of microalgae in the study area. Microalgae abundance ranged from 942 cells/L to 14,990 cells/L, with the highest mean abundance recorded in February during the dry season. Western creek indicated the highest abundance and species diversity compared to other stations at the bay with a significant difference in sample compositions (R = 0.236, P = 0.002). Pearson correlation coefficient showed that the environmental parameters; Total Dissolved Substances (0.61) and salinity (0.59) had a positive correlation with microalgae abundance. This relationship was significant at p < 0.05 for N = 12. In addition, these parameters had a strong influence on microalgae composition and abundance in the Western creek at Gazi Bay. While the microalgae in Mapononi and Doa were influenced by nitrate levels and pH respectively. Gazi Bay is recognized as an important breeding site for fisheries in the south coast of Kenya. Therefore, our findings may be useful in identifying areas within the bay that may be conserved in order to sustain the coastal community livelihood, and justify effective management of hinterland activities to minimize eutrophication.

March 2019 dengue fever outbreak at the Kenyan south coast involving dengue virus serotype 3, genotypes III and V.

The first description of a disease resembling dengue fever (DF) was in the 15th century slave trade era by Spanish sailors visiting the Tanzania coast. The disease, then associated with evil spirits is now known to be caused by four serotypes of dengue virus (DENV1-4) that are transmitted by Aedes mosquitoes. Kenya has experienced multiple outbreaks, mostly associated with DENV-2. In this study, plasma samples obtained from 37 febrile patients during a DF outbreak at Kenya's south coast in March 2019 were screened for DENV. Total RNA was extracted and screened for the alpha- and flavi-viruses by real-time polymerase chain reaction (qPCR). DENV-3 was the only virus detected. Shotgun metagenomics and targeted sequencing were used to obtain DENV whole genomes and the complete envelope genes (E gene) respectively. Sequences were used to infer phylogenies and time-scaled genealogies. Following Maximum likelihood and Bayesian phylogenetic analysis, two DENV-3 genotypes (III, n = 15 and V, n = 2) were found. We determined that the two genotypes had been in circulation since 2015, and that both had been introduced independently. Genotype III's origin was estimated to have been from Pakistan. Although the origin of genotype V could not be ascertained due to rarity of these sequences globally, it was most related to a 2006 Brazilian isolate. Unlike genotype III that has been described in East and West Africa multiple times, this was the second description of genotype V in Kenya. Of note, there was marked amino acid variances in the E gene between study samples and the Thailand DENV-3 strain used in the approved Dengvaxia vaccine. It remains to be seen whether these variances negatively impact the efficacy of the Dengvaxia or future vaccines.

Politics by night: histories of extraversion and rumours of body part theft on the south coast of Kenya

AbstractThis article analyses an episode of public anxiety when, in late 2013, word spread throughout Kenya’s rural Lunga Lunga constituency that politically connected gangs calledmumianiwere abducting and killing children for their eyes, tongues and genitals. The rapid spread of these rumours coincided with a regional drought, parliamentary election campaigns, and the apparent discovery of ‘devil worship paraphernalia’ inside a shipping container at the nearby port of Mombasa. I analyse the 2013mumianiscare in relation to histories of famine survival strategies, predatory patronage and occult speculation to argue that the 2013mumianipanic condensed and expressed these histories in figural rather than temporal form. As ‘constellations’ of coastal Kenyan historical consciousness,mumianiare (and have long been) a key feature of, and at the same time iconic of, a broader critical discourse about the dark side of political largesse – ‘politics by night’.

Dwindling Fish Catch in Kwale, Kenya: Vulnerable Southern Coast Marine Fisher Communities and Alternative Sustainable Livelihoods

Marine fisher communities of Kwale in the South Coast of Kenya have, for generations, depended nearly exclusively on fisheries and fish-based livelihoods. In recent times, dwindling fish catch has threatened their livelihoods. Diversification of livelihood sources is touted as a potential remedy, but much less is understood about the available alternative sustainable options and their viability. This study examined the potency and viability of the alternative livelihood options for the fishermen communities. It used a cross-sectional descriptive survey design premised on mixed qualitative and quantitative methods to collect and analyse the data from 346 randomly selected households. Emerging livelihood options with potency for adoption include apiculture, seaweed farming, agriculture, small business enterprises and mangrove conservation, among others. Preference is given to supplemental livelihood sources as opposed to alternative livelihoods. Implications for policy include the need for public extension services and training to invigorate households’ income.

Spatial patterns and environmental risks of ringnet fishing along the Kenyan coast

Ringnet fishing began in the early 20th century and is practised worldwide, mainly to target nearshore pelagic species. The method was introduced to Kenya’s coastal waters by migrant fishers from Tanzania. However, the impacts of this fishing gear remain poorly assessed. We assessed the spatial distribution of ringnet fishing effort and its possible effects on ecosystem components, such as coral reefs, marine megafauna and marine protected areas, on the south coast of Kenya. We tracked 89 ringnet fishing trips made from December 2015 to January 2016 and used spatial multicriteria analysis to determine hotspots of possible environmental risks. The results showed that habitat type and bathymetric profile influenced the spatial distribution of ringnet fishing effort. Mixed seagrass and coral habitats had the highest concentration of the effort. Most of the habitats in the study area were moderately exposed to the impacts of the ringnet fishery. The study identifies high-risk areas that require spatial measures to minimise possible environmental risks of the gear both to habitats and to endangered sea turtles.

Stock status and some biological aspects of Lethrinus lentjan (Lacapede, 1802) from the south coast of Kenya

The Pinkear Emperor (Lethrinus lentjan, Laćepède, 1802) is among the three demersal species dominating fish catches in the artisanal fishery on the Kenyan coast. Available data indicate that total landings of L. lentjan have declined over the past decade due to possible over-exploitation. This paper provides a brief account of the stock status of this species and biological aspects including length-weight relationship, body condition, and reproduction from a total of 575 fish specimens sampled. Sampling was done at Msambweni, Shimoni, Majoreni and Vanga fish landing sites on the south coast of Kenya from September 2016 to February 2017. Individual total length (TL, cm) and body weight (BW, g) was measured on site while some specimens were dissected for sex and gonad maturity analysis. Mortality, exploitation rate, length-weight relationship, condition factor, fecundity, and size at maturity (L50) were determined. Length frequency analysis indicated that L. lentjan was exploited above the optimum level, at E = 0.55 (exploitation rate). Growth was allometric with the length exponent (b = 2.95) being significantly &lt;3. Mean fecundity was 89,573 ± 9,841 eggs/female/year. Gonadosomatic index was highest in January (2.08 ± 0.20) suggesting a possible peak spawning period at this time. The study provides a brief scientific overview of L. lentjan as a baseline for future in-depth biological studies of this species along the Kenyan coast.

Stock status and some biological aspects of Lethrinus lentjan (Lacapede, 1802) from the south coast of Kenya

The Pinkear Emperor (Lethrinus lentjan, Laćepède, 1802) is among the three demersal species dominating fish catches in the artisanal fishery on the Kenyan coast. Available data indicate that total landings of L. lentjan have declined over the past decade due to possible over-exploitation. This paper provides a brief account of the stock status of this species and biological aspects including length-weight relationship, body condition, and reproduction from a total of 575 fish specimens sampled. Sampling was done at Msambweni, Shimoni, Majoreni and Vanga fish landing sites on the south coast of Kenya from September 2016 to February 2017. Individual total length (TL, cm) and body weight (BW, g) was measured on site while some specimens were dissected for sex and gonad maturity analysis. Mortality, exploitation rate, length-weight relationship, condition factor, fecundity, and size at maturity (L50) were determined. Length frequency analysis indicated that L. lentjan was exploited above the optimum level, at E = 0.55 (exploitation rate). Growth was allometric with the length exponent (b = 2.95) being significantly &lt;3. Mean fecundity was 89,573 ± 9,841 eggs/female/year. Gonadosomatic index was highest in January (2.08 ± 0.20) suggesting a possible peak spawning period at this time. The study provides a brief scientific overview of L. lentjan as a baseline for future in-depth biological studies of this species along the Kenyan coast.

Projecting Wet Season Rainfall Extremes Using Regional Climate Models Ensemble and the Advanced Delta Change Model: Impact on the Streamflow Peaks in Mkurumudzi Catchment, Kenya

Each year, many African countries experience natural hazards such as floods and, because of their low adaptative capabilities, they hardly have the means to face the consequences, and therefore suffer huge economic losses. Extreme rainfall plays a key role in the occurrence of these hazards. Therefore, climate projection studies should focus more on extremes in order to provide a wider range of future scenarios of extremes which can aid policy decision making in African societies. Some researchers have attempted to analyze climate extremes through indices reflecting extremes in climate variables such as rainfall. However, it is difficult to assess impacts on streamflow based on these indices alone, as most hydrological models require daily data as inputs. Others have analyzed climate projections through general circulation models (GCMs) but have found their resolution too coarse for regional studies. Dynamic downscaling using regional climate models (RCMs) seem to address the limitation of GCMs, although RCMs might still lack accuracy due to the fact that they also contain biases that need to be eliminated. Given these limitations, the current study combined both dynamic and statistical downscaling methods to correct biases and improve the reproduction of high extremes by the models. This study’s aim was to analyze extreme high flows under the projection of extreme wet rainfall for the horizon of 2041 of a Kenyan South Coast catchment. The advanced delta change (ADC) method was applied on observed data (1982–2005), control (1982–2005) and near future (2018–2041) from an ensemble mean of multiple regional climate models (RCMs). The created future daily rainfall time series was introduced in the HEC-HMS (Hydrologic Engineering Center’s Hydrologic Modeling System) hydrological model and the generated future flow were compared to the baseline flow at the gaging station 3KD06, where the observed flow was available. The findings suggested that in the study area, the RCMs, bias corrected by the ADC method, projected an increase in rainfall wet extremes in the first rainy season of the year MAMJ (March–April–May–June) and a decrease in the second rainy season OND (October–November–December). The changes in rainfall extremes, induced a similar change pattern in streamflow extremes at the gaging station 3KD06, meaning that an increase/decrease in rainfall extremes generated an increase/decrease in the streamflow extremes. Due to lack of long-term good quality data, the researchers decided to perform a frequency analysis for up to a 50 year return period in order to assess the changes induced by the ADC method. After getting a longer data series, further analysis could be done to forecast the maximum flow to up to 1000 years, which could serve as design flow for different infrastructure.

Parental Attitudes, Roles and Influences on Decision Making for Child Well-being on the South Coast of Kenya—a Descriptive Study

ABSTRACT While it is well-accepted that mothers play a key role in child health outcomes, the role of the father is less well understood. This study, the first of two investigations of the relationship between the social environment and child health, growth and development, was nested in a child nutrition programme carried out in Kwale County. At present child health services are largely administered through government Mother and Child Health programmes. Previous community consultations have raised the need to include all family members, particularly fathers, in the process of addressing child health and development issues. To provide a background to planning for inclusion of the wider family this study investigated local attitudes and beliefs towards parenting and how these may influence child health outcomes. In this study, we used qualitative in-depth interviews of 61 co-habiting couples with fathers and mothers interviewed separately, analysed using NVivo 10 software, to look for patterns of responses with regards to attitudes and behaviours relevant to child health. The study findings suggested that both mothers and fathers overall valued their status as parents and were willing to be involved in promoting the well-being of their children. Fathers and mothers saw that they carried out a different role, and drew on different influences in their decision making and role definition. The main barrier to direct paternal involvement in the health care of their children was reported to be the cost of attendance at clinics, both in terms of time and money. Innovation in how medical services engage with families is required to increase the supportive role that fathers can provide by using opportunities such as community meetings where men gather to explain child health risks and preventative measures.

Impact of pollution on the feeding, bioturbation and biomass of Uca annulipes in Gazi and Mikindani mangroves, Kenya

Owuor MA, Aloo-Obudho P, Cannicci S, Gitundu JK. 2017. Impact of pollution on the feeding, bioturbation and biomass of Uca annulipes in Gazi and Mikindani mangroves, Kenya. Ocean Life 1: 61-68. Marine pollution is one of the main anthropogenic factors globally recognized that affect the estuarine and coastal ecosystems. Mangroves received the pollutant since they are intercepting between land and ocean. Despite the utilization of natural mangrove as pollution buffers, how these pollutants might impact the biodiversity of the ecosystems remains a great question. Here, we aimed at determining the impact of pollution on the feeding, bioturbation, and biomass of the fiddler crab Uca annulipes in two regions, Gazi and Mikindani, all along the Kenya Coast. The mangroves in Mikindani on Tudor creek represented peri-urban mangroves that are heavily impacted by municipal wastewater. Meanwhile, the mangroves in Gazi Bay in the South Coast of Kenya served mangroves not affected by direct sewage input. Furthermore, Crabs U. annulipes are one of the most important groups of mangrove epifauna. We adopted a stratified nested design to investigate the impacts of pollution on the feeding, bioturbation, and biomass of U. annulipes. We applied a layered random sampling approach at each site that spanned in 2 × 2 m2 quadrats in desert and Avicennia zones during July, August and October 2005. The data collection depended on each full moon springs and new moon springs. Different parameters were measured, chlorophyll a (Chl a) concentrations in the feeding pellets and unprocessed soils, amount of bioturbated clays (expressed as dry weight of excavated material and feeding pellets), and biomass (dry weight) of U. annulipes. Four-factor Analysis of Variance (ANOVA) tests were applied to determine whether there was a significant difference in feeding, bioturbation, and biomass of U. annulipes within the two sites. Our findings show substantial differences in chlorophyll a concentration in the feeding pellets in the Avicennia zone of the peri-urban mangroves. Moreover chlorophyll a level did not vary between the processed and unprocessed soils in the Avicennia zone. In Gazi, a significant difference in the bioturbated material was recorded compared to Mikindani. The results demonstrate a consistent increase in crab biomass at the peri-urban site, then the non-urban mangroves. The Avicennia zone of the suburban location had a higher U. annulipes biomass compared to the non-urban Gazi. There was no association between the mass of bioturbated material and Uca biomass. The results also show that the amount of excavated material did not relate to the Uca biomass.

Drivers, patterns and velocity of saltwater intrusion in a stressed aquifer of the East African coast: Joint analysis of groundwater and geophysical data in southern Kenya

Fresh groundwater resources in coastal East Africa are crucial for the region's socio-economic development but are under threat of salinization caused by changes in recharge patterns and increasing abstraction. With the aim of establishing the drivers behind saltwater intrusion and its current spatial extent, we studied the Kenyan South Coast aquifer, a representative, strategic aquifer under increased pressure. Investigations included electrical resistivity tomography (ERT) surveys and in-situ groundwater measurements (water table and basic quality) together with the analysis of available long-term climatic and borehole monitoring data. Over the last 40 years, groundwater electrical conductivity values at the well field increased by about three times and groundwater levels declined by 1–3 m over the last decade. When put in perspective with the long-term climate (rainfall, temperature) and abstraction records, these trends in groundwater appear to be primarily driven by increased borehole abstraction (+400 m3/day per year in average), whereas observed increasing temperature (+0.02 °C per year) and decreasing rainfall (−0.8 mm per year) could potentially act as a secondary control through reduced recharge. However the low statistical significance obtained for both rainfall and temperature trends over the observation period suggests that no clear conclusion can be made with regards to long-term climate impact on groundwater. Groundwater quality mapping showed that proximity to the ocean, presence of abstraction well-fields and regional geology control groundwater salinity patterns at regional scale. Locally, geophysical data showed that, saltwater intrusion spatial patterns are controlled by local aquifer lithology, groundwater abstraction and freshwater recharge in floodplains. Comparison with previous (1984) resistivity data showed that the saltwater front has advanced toward the well-field by up to 2 km and rose by up to 80 m over the last 30 years, which corresponds to a maximal velocity of about 60 m/y horizontally and 2 m/y vertically. Implementation of groundwater management strategies such as sustainable groundwater exploitation, sourced alternative water supply, and managed aquifer recharge are required to mitigate the effects of seawater intrusion along the East African coastal strip.

Comparing an ecosystem approach to single-species stock assessment: The case of Gazi Bay, Kenya

Abstract Gazi Bay located on the Kenyan South Coast is a semi-enclosed shallow tropical coastal ecosystem supporting an economically important multi-species and multi-gear artisanal fishery. In this study, we integrated the available scientific information of the system to develop a preliminary trophic mass-balance model to characterize the ecosystem structure and functioning, evaluate the ecological impacts of fishing on the ecosystem, and compare the results of the ecosystem assessment to those of previous single-species stock assessments. The model includes 23 functional groups aggregated into linear food chains, which resulted in nine discrete trophic levels sensu Lindeman (1942). Results from the mixed trophic impacts showed a bottom-up control in the system where herbivory dominated the energy flow to higher trophic levels but with a significant export of detritus out of the system. With a mean transfer efficiency of 12.6%, Finn cycling index 7.3%, path length 2.7, system omnivory index 0.19, and system ascendency and overhead 27 and 73%, respectively, it would appear that Gazi Bay is immature and perturbed likely due to fishery-induced exploitation. Overall, the fishery is operating at a level of primary consumers with a mean trophic level of the catch of 2.38. Fishing mortality is by far the leading cause of total mortality with the computed exploitation rates suggesting heavy exploitation of the key commercial species (F/Z > 0.5). A comparison of the results of the percentage of primary production required to sustain fisheries and the average trophic level of catch (%PPR–TLc) with those from similar tropical coastal systems shows that Gazi Bay is comparable to some of the most intensively exploited coastal ecosystems. This implies the impacts of the fishery are evident both at the species and ecosystem level, and there may be a need for precautionary measures for fisheries management.

Risk factors associated with rural water supply failure: A 30-year retrospective study of handpumps on the south coast of Kenya

An improved understanding of failure risks for water supplies in rural sub-Saharan Africa will be critical to achieving the global goal of safe water for all by 2030. In the absence of longitudinal biophysical and operational data, investigations into water point failure risk factors have to date been limited to cross-sectional research designs. This retrospective cohort study applies survival analysis to identify factors that predict failure risks for handpumps installed on boreholes along the south coast of Kenya from the 1980s. The analysis is based on a unique dataset linking attributes of >300 water points at the time of installation with their operational lifespan over the following decades. Cox proportional hazards and accelerated failure time models suggest water point failure risks are higher and lifespans are shorter when water supplied is more saline, static water level is deeper, and groundwater is pumped from an unconsolidated sand aquifer. The risk of failure also appears to grow as distance to spare part suppliers increases. To bolster the sustainability of rural water services and ensure no community is left behind, post-construction support mechanisms will need to mitigate heterogeneous environmental and geographical challenges. Further studies are needed to better understand the causal pathways that underlie these risk factors in order to inform policies and practices that ensure water services are sustained even where unfavourable conditions prevail.