ABSTRACT This study evaluates the habitat characteristics, fishing effort, and production, as well as changes in the individuals, such as changes in size frequency, of the spawning aggregations of mutton snapper Lutjanus analis and grey triggerfish Balistes capriscus, caught in the Chinchorro Bank Biosphere Reserve (CBBR), Mexico. The mutton snapper aggregation was located in coral patches, while the spawning aggregation of grey triggerfish was located on the windward terrace of the reef flat. Fishery data was obtained for the duration of the spawning event in 2008, with a total of 5 days for mutton snapper and 4 days for grey triggerfish. The fishery recorded a total of 830 mutton snappers, with individual sizes ranging from 40 to 77 cm in fork length (FL). Individual size and catch per unit effort (CPUE) decreased through time, with the lowest values presented at the end of the 5 days. In contrast, a total of 665 grey triggerfish were recorded in the catch, ranging from 45 to 61 cm (FL) with the largest sizes caught at the end of the fishing period, concurrently with the lowest CPUE. A lack of governance allowed both species to be harvested during their spawning aggregations. The creation of an international body composed of fishers, managers, conservationists, and scientists from the countries belonging to the Mesoamerican Reef System is urgently required to look for agreements in conservation and management strategies of these commercially important species.