A frequent expectation of the use of marine reserves in management of coral reef fisheries is maintenance or enhancement of yields to areas adjacent to reserves by adult (post-settlement) movements from reserve to fished areas (the so-called spillover effect ). This paper reports on some circumstantial evidence derived from underwater visual census monitoring of densities of large predatory coral reef fish [Serranidae (Epinephelinae), Lutjanidae, Lethrinidae and Carangidae as a group] inside and adjacent to a small marine reserve at Apo Island over a 10 yr period (1983 to 1993). Significant positive correlations of both mean density and species richness of large predatory fish with duration of reserve protection (from 1 to 11 yr) were observed in both the reserve and non-reserve areas surveyed. The visual census data is consistent with a proposed model of adult fish export from the reserve to the non-reserve areas.