Whale shark abundance, spatial distribution and effective tourism areas in the northern Mexican Caribbean

Every year, from June to September, the whale shark (Rhincodon typus) is present in the Mexican Caribbean and has become a highly attractive tourist resource. In this study, we assess the spatial and temporal distribution of whale sharks and estimate the size of the effective tourism area from data collected between 2016 and 2021. The main whale shark aggregation site in the Mexican Caribbean is called 'El Azul', it has an average size of 400 km2. Using aerial survey data, we found 37 whale shark aggregations where we counted 1–170 individuals and 16–150 tourist boats. The average size of the area covered by these groups was 2.9 km2. The highest density of whale sharks was recorded in 2020 (48 whale sharks per km2) and the lowest in 2021 (5 whale sharks per km2). Estimating the effective tourism area (where whale shark tourism takes place) within the entire aggregation area is important to refine tourism carrying capacity calculations and to avoid miscalculations that could lead to over-exploitation of whale shark tourism activities with negative consequences for the species. The information from this study is directly applicable to adaptive ecotourism management, improving the sustainability of whale shark tourism, and biological monitoring.