The Mayor Island (Tuhua) marine reserve was created in January 1993. A pre-reserve survey had already compiled algae, invertebrate, and fish species lists, with distributional data and habitat descriptions (Jones & Garrick 1991). They recorded a total of 54 fish species and presented the relative abundances of each. These data were essential for site selection and replication in the present survey,which was undertaken in March/April 1993, only 3 months after the reserve was established. Fieldwork for the present survey was undertaken by Department of Conservation (Bay of Plenty Conservancy) and NIWA-Oceanographic staff, as well as 2nd-year marine biology students from the Bay of Plenty Polytechnic. It was designed to provide background data on numbers of fish species present, numbers of individuals, their distribution within sites and depth, and to ascertain whether there were differences between "reserve" and "control" sites. These data would then be available for comparisons with those obtained after the reserve had been in place for some time, and would provide assistance for reserve management as well as the wider scientific questions recently outlined by Rowley (1992) on whether marine reserves act as spillover areas to enhance fisheries adjacent to their boundaries. Only the presence data is presented in this dataset. The analysis of the fish length data is given in the final report by Grange (1993).