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Microbioerosion rates and microbioeroder community structure were studied in four Kenyan protected coral-reef lagoons using shell fragments of Tridacna giant clams to determine their response to the influence of terrestrial run-off. Fourteen different microbioeroder traces from seven cyanobacteria, three green algae and four fungi species were identified. The river discharge-impacted reef and ‘pristine’ reef showed similar composition but higher microbioeroder abundance and total cyanobacteria- and chlorophyte-bioeroded areas when compared with the other study reefs. Cyanobacteria dominated during the north-east monsoon (NEM) relative to the south-east monsoon (SEM) season, with algae and cyanobacteria being major microbioeroders in the river-impacted and pristine reefs. The rate of microbioerosion varied between 4.3 g CaCO3 m−2 y−1 (SEM) and 134.7 g CaCO3 m−2 y−1 (NEM), and was highest in the river-impacted reef (127.6 g CaCO3 m−2 y−1), which was almost double that in the pristine reef (69.5 g CaCO3 m−2 y−1) and the mangrove-fringed reef (56.2 g CaCO3 m−2 y−1). The microbioerosion rates measured in this study may not be high enough to cause concern with regard to the health and net carbonate production of Kenya’s coral reefs. Nevertheless, predicted increases in the frequency and severity of stresses related to global climate change (e.g. increased sea surface temperature, acidification), as well as interactions with local disturbances and their influence on bioerosion, may be increasingly important in the future. [ABSTRACT FROM AUTHOR]

The potential to improve the management of fisheries in Pemba, Mozambique, were explored by evaluating stakeholder's preferences for management and the key institutional design elements of the fisheries organisations or community councils of fisheries (CCPs). We interviewed fishers, community leaders and government fisheries officers regarding (1) their perceptions about different fisheries restrictions, (2) their socio-economic conditions, and (3) the institutional design and rules of the CCP arrangements. Fishers had low levels of education (<4 years) and biweekly expenditures of around US$100, and they were permanent residents of their villages, being part of large households (9–12 members). Apart from effort restrictions, respondents’ perceptions were similar and strongly supported a range of fisheries regulations, particularly gear and minimum size restrictions. The suggested minimum size of captured fish was 20.6 cm (SD 3.0), whereas the suggested size of closed areas was 8.4 km2(SD 2.0). Fishers associated with community or conservation groups generally had more positive views of spatial closures and other less-preferred management restrictions. A number of the essential design principles for fisheries rules were in place with the exception of graduated sanctions. There is a need for strengthening groups, forums, leadership training in finance, and means to implement transparency and graduated sanctions. [ABSTRACT FROM AUTHOR]