The marine ornamental market in Brazil (Southwestern Atlantic) frequently trades prohibited and endangered species, and threatens the ecosystem role of cleaning mutualism

The marine aquarium trade often depends on organisms collected from reef environments. However, reefs are declining because of multiple anthropogenic stressors, and sustaining functional diversity is critical for main-taining reef resilience. Collection of organisms for the aquarium trade is growing in the Southwestern Atlantic, particularly in Brazil, but there is a lack of studies on its potential ecological impacts on Brazilian reefs. Therefore, we (i) gathered data on the native fish and invertebrate species exported (2012-2018) and traded internally (2019) through governmental databases and use of the snowball method, and (ii) using interaction network analyses, assessed whether overharvesting the most targeted cleaner species would disrupt the ecological function of cleaning mutualisms. Results show that 90 % of the fish exported between 2011 and 2018 belonged to 10 species, with three of them considered cleaner and with no prohibited and endemic species. The internal trade, however, included two prohibited species, three endemics and four cleaners within its top five. For invertebrates, there were four prohibited species and three cleaners in the top ten. Removal of the three most traded cleaner fish species from the mutualistic networks severely reduced number of interactions. Therefore, unlike the external trade, the internal market of marine ornamentals in Brazil is often associated with illegal practices and targets cleaning organisms in a way that may add pressure to an already fragile environment. We argue that this scenario is a consequence of lack of ordinance and adequate policies, that need prompt reassessment.