A cage experiment was used to exclude the epibenthos from the Cenops tagal mangrove sediment at Gazi Bay, Kenya. This made it possible to study Interactions with the melobenthos (in terms of predation, food competition and food enhancement). The density of the meiobenthic taxa and nematode genera and a broad range of abiotic variables were followed in a depth profile over 1 yr of caging. There was a signif~cant exclusion effect in the upper sediment layer for total meiofauna, nematodes and oligochaetes dunng the first 2 mo and for copepods during the last 6 mo of caging. The density of the most common predatory and microalgae-feeding nematodes in particular tended to increase in the surface layers as well as the percentage of muddy detritus and pigment concentration. Food competition with the epibenthos seems to be most important in structuring the nematode community. This is suggested by the parallel exclusion effect on muddy detritus, pigments and nematode composition and the lack of evidence for upward nematode migration in the cage during the experiment. The same can be concluded for the oligochaetes, whereas copepod densities are believed to be controlled more by predation. These findings indicate that the meiofauna community of the C. tagal mangrove sediment (consisting of about 95% nematodes and oligochaetes) is part of a rather isolated, detrital food web with only minor predator-prey interactions with the epibenthos

Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissemination of high quality research generated in the Western Indian Ocean (WIO) region, in particular on the sustainable use of coastal and marine resources. This is central to the goal of supporting and promoting sustainable coastal development in the region, as well as contributing to the global base of marine science. The journal publishes original research articles dealing with all aspects of marine science and coastal management. Topics include, but are not limited to: theoretical studies, oceanography, marine biology and ecology, fisheries, recovery and restoration processes, legal and institutional frameworks, and interactions/relationships between humans and the coastal and marine environment. In addition, Western Indian Ocean Journal of Marine Science features state-of-the-art review articles and short communications. The journal will, from time to time, consist of special issues on major events or important thematic issues.

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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 sediments disturbance following polychaete bait harvesting. The study was conducted in three sites experiencing different bait harvesting intensities in Mida Creek, Kenya. Sediment samples were collected from the mudflats during low tide, preserved in 5% formalin and transported to the laboratory for processing and identification of nematodes. The highly disturbed site recorded the lowest nematode genus richness while the less disturbed sites had the highest. Overall, the most abundant nematode genera in the non-disturbed (Dabaso) and less disturbed sites (Kirepwe) were selective deposit feeders (Spirinia and Terschellingia), while most disturbed sites (e.g. Mayonda) had predators/omnivores (Pheronus, Aporcelaimellus) and selected members of the genus Spirinia. The disturbed site was characterised by low nematode diversity (H’) and low dominance (D) while the non-disturbed and less disturbed sites had higher diversity and dominance. Clearly, nematode community assemblage, diversity and feeding guilds changed following disturbance to a low diversity that favoured higher proportions of predator/omnivore taxa.

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