Expansion of aquaculture parks and the increasing risk of non-native species invasions in Brazil

Aquaculture is the main vector for introduction of non-native species in Brazil and around the world. Despite the potentially serious and irreversible ecological impacts caused by non-native species, they continue to be in many cases the preferred option in aquaculture farms, of which the recent plans of aquaculture expansion promoted by the Brazilian Government are an emblematic example. In this study, we present a survey of publicly available information on aquaculture parks to be installed across the Brazilian territory, with emphasis on species status as native or non-native, and discuss the implications for the conservation of aquatic biodiversity. One hundred and thirty-nine aquaculture parks (APs), with a total of 1556 sites covering 941.38 hectares, have been called for bids. Among these, 122 APs will contain at least one non-native species, and 68 APs will be based exclusively on their cultivation. A predictable consequence is the enhancement of propagule pressure in surrounding aquatic ecosystems, increasing the risk of non-native species establishment or persistence, which will likely intensify the environmental impacts already in course in four major river basins and along the Brazilian coast. These impacts will add up to more direct effects of aquaculture farming – for example elevated input of nutrients and organic matter – and include changes in habitat and water quality, spread of diseases, biotic homogenization, loss of population viability resulting from hybridization and outbreeding depression, and the local extirpation of native species.