Agnes WN Muthumbi

University of Nairobi | UON · School of Biological Sciences

Nematodes are among the most abundant organisms in marine ecosystems where they play a critical role in nutrient cycling, provision of nourishment to the higher organisms in the food web, pest control, and act as disease-causing vectors. This study determined the abundance and community structure of nematodes in three plots of Rhizophora mucronata...

Nematodes are among the most abundant organisms in marine ecosystems where they play a critical role in nutrient cycling, provision of nourishment to the higher organisms in the food web, pest control, and act as disease-causing vectors. This study determined the abundance and community structure of nematodes in three plots of Rhizophora mucronata...

Traditionally basket traps, baited with gastropods, seagrass, among others, deployed in nearshore fishery, are typical to tropical coastlines. Although fish landings from such fishery are documented, bait utilized remains sketchy. The Indo-Pacific Mangrove mudwhelk ( Terebralia palustris ) are keystone species, threatened by habitat degradation but...

Meiofauna communities were analysed from samples collected at four stations on the Kenyan continental shelf (Shimoni, Kwale, Mombasa and Kilifi) during the maiden cruise of the RV Mtafiti, 12–21 December 2015. Nematodes were identified to genus level, and their distribution and composition were mainly influenced by grain size distribution, a findin...

Enhanced growth and survival indicate a quality diet important in the production of quality fish larvae. Diet’s quality heavily depends on the quality of its protein which varies with inclusion levels and sources. This Influences stress responses and compromises wellbeing larvae due to diets suboptimal provision of nutritional requirements. However...

The biodiversity of marine and coastal habitats is experiencing unprecedented change. While there are well-known drivers of these changes, such as overexploitation, climate change and pollution, there are also relatively unknown emerging issues that are poorly understood or recognized that have potentially positive or negative impacts on marine and...

Sustainable wetland management is a focus of many countries worldwide. These mainly use protection as a key policy directive for conservation. However, avoidance directives tend to disenfranchise local populations. Thus, such management is often resisted and rarely effective. Tailoring management strategies to user preferences allows conservation t...

Agricultural practices play a major role in influencing soil fauna abundance and diversity. Interest in these practices has increased owing to the growing need for sustainable agricultural systems in this era of increasing agricultural intensification. In this study, two paddy rice farming pathways (smallholder and large-scale commercial) and an ad...

In the Western Indian Ocean (WIO), more than 76 records from peer-reviewed and grey literature identified approximately 60 invertebrate taxa harvested for bait and food. The most diverse phyla were Mollusca, followed by Arthropoda and Annelida, with few records of Porifera, Nemertea and Echinodermata. Importance of each phylum differs according to...

Microplastic pollution has been recognised as a global threat in marine environments and a danger to prey, predators and humans. Yet, there have been few studies in the western Indian Ocean, specifically along the Kenyan coast, which makes it difficult to estimate the extent of such pollution in the region. This is the first study on microplastics...

Yellowfin tuna, Thunnus albacares (Bonnaterre, 1788) is a highly migratory and important commercial fishery species. Data on length-frequency, growth parameters and mortality rates of yellowfin tuna in the coastal waters of Kenya is limited. We assessed Catch Per Unit Effort (CPUE), size distribution, growth parameters and mortality rates based on...

Microplastics are plastic particles less than 5 mm in diameter. These plastics mostly result from degradation of larger plastics. Due to their small size, they are often accidentally ingested by sea faunas, particularly the deposit and filter feeders. However, information on the ingestion of microplastics by sea fauna such as jellyfish is rare. Thi...

Land use/cover (LULC) change is a major concern in Africa’s river basins and policy makers, environmentalists and other stakeholders tackling biodiversity and sustainable development issues in these watersheds require accurate information on past, present and future LULC projections to develop management strategies for the concerned watersheds. Thi...

Sediment disturbance in marine environments is caused by activities including polychaete bait harvesting, trawling, dredging, sediment erosion and treading. These activities affect the benthic communities by changing the densities, community assemblage and diversity. The aim of this study was to evaluate the potential of nematodes as indicators of...

Microplastic pollution has been recognized as a global threat in marine environments and a danger to prey, predators and humans. Yet there have been limited studies in the Western Indian Ocean (WIO) and along the Kenyan coast making it difficult to estimate the extent of such pollution. This is the first study on microplastics (MPs) in the surface...

The United Nations Decade of Ocean Science for Sustainable Development presents an exceptional opportunity to effect positive change in ocean use. We outline what is required of the deep-sea research community to achieve these ambitious objectives.

The ocean plays a crucial role in the functioning of the Earth System and in the provision of vital goods and services. The United Nations (UN) declared 2021–2030 as the UN Decade of Ocean Science for Sustainable Development. The Roadmap for the Ocean Decade aims to achieve six critical societal outcomes (SOs) by 2030, through the pursuit of four o...

Microplastics (MPs) are plastics less than 5 mm in diameter. Their small size renders them invisible to deposit- and filter-feeding fauna, leading to unintentional ingestion. This study investigated the presence of MPs in an oyster (Saccostrea cuccullata) and three species of brachyuran crabs (Tubuca dussumieri, Cranuca inversa and Gelasimus vocans...

The study was conducted to evaluate the potential of selected seaweeds in Nile tilapia Oreochromis niloticus fingerlings diets. Two species of seaweeds, Hypnea cornuta, and Hypnea muscifomis were sampled from the Kenyan coast and their chemical composition determined. They both had crude protein content above 20%. Five diets with crude protein of 3...

Abstract Endobenthic fauna diversity, density and relative abundance were studied along the Kenyan continental shelf at four stations (Shimoni, Kwale, Mombasa and Kilifi) sampled during the R/V Mtafiti’s maiden cruise between 12th and 21st December, 2015. A total of 16 macrobenthic taxa were recorded, with Amphipoda and Polychaeta dominating at all...

Psammonema waweri is the third species in the recently described genus Psammonema, (Verschelde & Vincx, 1995) after the type species P. ovisetosum and P. kuriani ( Jacob et al., 2015). It is characterized by large loop-shaped amphids that overlap both the anterior and posterior part of the cephalic capsule, a lateral alae that begins posterior of t...

Intensification of aquaculture may result in more fish culture waste being discharged into adjacent rivers and streams. Due to composition of such wastes, ecological conditions in waterbodies may be adversely affected. We determined the ecological consequences of freshwater land-based Tilapia farms on headwater streams using macroinvertebrate commu...

Mangrove gastropods and hermit crabs are frequently harvested for use as bait by artisanal trap and hook fishers, along the Kenyan coastline and elsewhere. In addition to mangrove degradation, the harvesting of shelled invertebrates, can alter shell availability and hence survival of these interdependent fauna. This study compares shell morphometri...

Although artisanal commercial and net fishers landings has received attention, the morphometrics of bait fisher landings is poorly documented. This is in spite of the importance of such data to infer fished stock growth and developmental status in order to reduce excessive removal of immature and highly fecund fish. This study compares fish species...

This study investigated the presumed nursery function of mangroves for the ichthyofauna in East African swamp forests, Mida Creek. The species and size composition of the fish fauna and their trophic interactions were studied for five stations.Samples were collected during 5–6 consecutive days close to spring tide in mid-July 2011. Fish were caught...

AbstractA study was carried out across the continental shelf and slope in the Western Indian Ocean along the Kenyan margin to unravel depth‐related species diversity patterns portrayed by different nematode families. Sediment samples were collected along four bathymetric transects at 20, 50, 200, 500, 1000 and 2000 m. Three nematode families were s...

Recovery of Rhizophora mucronata mangrove ecosystems was investigated by assessing the physical characteristics of their sediments and the forest densities, community composition and diversity of macro-endofauna. This was done in 5- and 10-year reforested mangroves and natural and degraded controls. Natural and 10-year reforested sites were charact...

The great variety of geological and hydrological conditions in the deep sea generates many different habitats. Some are only recently explored, although their true extent and geographical coverage are still not fully established. Both continental margins and mid-oceanic seafloors are much more complex ecologically, geologically, chemically and hydr...

The great variety of geological and hydrological conditions in the deep sea generates many different habitats. Some are only recently explored, although their true extent and geographical coverage are still not fully established. Both continental margins and mid-oceanic seafloors are much more complex ecologically, geologically, chemically and hydr...

The great variety of geological and hydrological conditions in the deep sea generates many different habitats. Some are only recently explored, although their true extent and geographical coverage are still not fully established. Both continental margins and mid-oceanic seafloors are much more complex ecologically, geologically, chemically and hydr...

The decrease of nematode size with water depth is well documented in the literature. However, many nematode size data sets originate from bathymetric gradients, with strong bias towards deep-water, muddy sediments. This has narrowed our perception of the environmental factors that may influence nematode morphometry. Here we perform a morphometric a...

The biodiversity of meiofauna in the coral degradation zone along the Kenyan coast was examined with special emphasis on the most abundant taxa, Copepoda and Nematoda. Communities from three microhabitat types (coralline sediment, coral gravel and coral fragments) at two locations (Watamu and Tiwi Beach) were analysed. The total number of meiofauna...

The gastropod Terebralia palustris often dominates the surface of muddy to sandy substrates of intertidal mudflats and mangrove forests, where they clearly destabilize the sediment. In the present study, it was investigated whether and to what extent the behaviour of juvenile and adult snails differs among habitats (mudflat vs. mangrove stand) in a...

This study investigated the distribution of Molgolaimus species (Nematoda) at different hierarchical spatial scales and observed the turnover of species along bathymetrical transects and among transects in two separate geographical regions. Samples from six transects (200–2000 m) from the Southern Oceans (SO) and four bathymetric transects (50–2000...

Nematode genus assemblages were identified from four locations in coral degradation zones (CDZs) along the African east coast: Watamu and Tiwi Beach (Kenya) and Matemwe and Makunduchi (Zanzibar). Three microhabitat types were distinguished: coralline sediment, coral gravel and coral fragments. Nematode community composition was comparable to that o...

This book contains 22 chapters on various aspects of freshwater nematode ecology and taxonomy. Subjects covered include the techniques for processing freshwater nematodes, the composition and distribution of free living freshwater nematodes, their abundance, biomass and diversity, the production of freshwater nematodes, their feeding ecology, patte...

Metazoan meiofauna and in particular nematode densities, diversity, community structure were studied in relation to water depth (20 m, 50 m, 500 m, 1000 m and 2000 m) along four bathymetric transects in the Western Indian Ocean off the Kenyan coast. Nematode densities ranged between 276–944 ind./10 cm2, which is comparable to values from other olig...

Meiofauna and macrofauna communities and several sediment characteristics were compared between a slope situated far from the coast (Goban Spur) and two transects across the Iberian Margin with steep slopes and close to the shore. The northern Galician transect (off La Coruña) was situated in an area subjected to wind-induced upwelling events. The...

We studied the composition and variation of nematode body size as a function of nematode depth in the sediment and water depth at 18 stations, ranging from 137 to 4951 m depth, along the Galician margin (NE Atlantic). The analysis is based on more than 10000 individuals and demonstrates that nematodes have adapted mainly in response to the vertical...

Nine species are described from the genera Aponema Jensen, 1978, Bolbolaimus Cobb, 1920, Calomicrolaimus Lorenzen, 1976, Ixonema Lorenzen, 1976 and Microlaimus de Man, 1880. Aponema decraemerae sp. n. is characterised by sexual dimorphism in the size of the amphids, short cephalic sensilla, spicules with a poorly developed capitulum and conical cyl...

Seventeen new and known species of the familyChromadoridae are described. The genus Dichromadora is represented by five species. Dichromadora longicaudata sp.n. is characterised bya slender body and thin long tail; Dichromadoragathuai sp.n. is characterised by a blunt anteriorend, a raised lateral alae and a gubernaculum that isserrated on the post...

Twelve new and known species of the genera Sabatieria, Cervonema, Paramesonchium, Hopperia and Dorylaimopsis and one new genus, Kenyanema are described from the Indian Ocean and S. pisinna Vitiello, 1970 from the Mediterranean Sea. Sabatieria lucia sp. n. is characterised by short but distinct inner and setiform outer labial sensilla and long (4–5...

The diagnostic characteristics of ActinonemaCobb, 1920 and Rhips Cobb, 1920 are reviewed andtheir importance for genera diagnosis assessed. Threespecies of Actinonema and one species of Rhips are described. Actinonema longicaudatumSteiner, 1918 is characterised by short (2–3 mlong) anterior sensilla, cylindrical body with arather narrow anterior en...

Seven species of the Acantholaimus aredescribed. Acantholaimus vermeuleni sp.n. ischaracterised by labial and cephalic sensilla thatare located at the same level, two post amphidialsetae on the dorso-lateral side and a poorlydeveloped stoma without distinct teeth. Acantholaimus verscheldi sp.n. is characterised bya narrow elongate pharyngeal region...

Six new species of the genus Molgolaimus DITLEVSEN, 1921 are described from the Indian Ocean. Molgolaimus abyssorum n.sp. is characterised by a small body (L = 287-370 μm), amphids close to the anterior end (2-3 μm behind the anterior end), short (2 × abd) curved spicules and absence of pre-cloacal supplements. Molgolaimus tyroi n.sp. is characteri...

A new genus, Papillonema gen.n., is erected to accomodate the two species P. danieli gen. et sp. n. and P. clavatum (Gerlach, 1957) comb.n. from intertidal sediments of a tropical mangrove. Papillonema gen.n. is characterized by prominent papilliform labial sensillae, an elongate muscular terminal bulb (up to 60% of pharyngeal length), and three pr...

Three new species of nematodes (Chromaspirina okemwai sp.n., Pseudochromadora interdigitatum sp, n. and Eubostrichus africanus sp. n.) from Ceriops mangrove sediments and one new species (Eubostrichus longosetosus sp. n.) from the North Sea, along the Belgian coast, are described. Chromaspirina okemwai is characterized by four cephalic sensillae an...

Samples were taken for meio-, meso-(not yet sorted) and macrofauna and for sediment analyses along two transects at the Iberian Margin in June/July 1997. The first transect was from the coast off La Coruña to the abyssal plain at water depth ranging from 175 to 4909 m and the second transect from the Galicia Bank perpendicular to the coast. Macrofa...