Abstract.Experiments were conducted to determine the decomposition rate of mangrove wood in two areas of differing water nutrient concentrations. Stakes were prepared from prop roots ofRhizophora inangleand from branches ofAvicennia. ConocarpusandLagguncularia. and tied in the natural habitat at two sites—Man‐of‐war Cay (high nutrient concentrations) and Twin Cays (low nutrient concentrations) — off the Belize coast. The stakes were retrieved after 4–24 months and the vertical zonation and succession of higher marine fungi was recorded. Consumption of wood by shipworms (Teredo bartschi), the major decomposers, was measured by digital analysis of the area of wood consumed by these boring organisms.SummaryA total of 20 species of marineAscomycotina, 2Basidiomycotina, and 6 anamorphic fungi were identified from the experimental stakes. Differences in species composition between the two sites of Twin Cays and Man‐of‐war Cay (Belize) were observed, as well as a certain degree of patterning in the vertical distribution of fungi. AmongAscomycotina, members ofHalosphaerialesshow a definite tendency to thrive at greater depths than other species. Mangrove decomposition by shipworms was clearly higher in the nutrient‐rich waters of Man‐of‐war, where the stakes were already heavily riddled after 8 months and had mostly disappeared after 2 years, while they were still intact at the other site. No significant difference in degradation of the 4 species of