Projecting environmental suitability areas for the seaweed Gracilaria birdiae (Rhodophyta) in Brazil: Implications for the aquaculture pertaining to five environmentally crucial parameters

Climate change has affected the distribution of economically important marine organisms worldwide. Seaweeds are among the most cultivated marine organisms in aquaculture and whose production has been increasing annually. Environmental Suitability Modeling (ESM) has currently been applied to predict the future distribution of economically important species concerning impacts from climate change. In this context, this study aimed to project how a global change scenario (RCP8.5) will affect the cultivation of the red seaweed Gracilaria birdiae in the Brazilian coast based on ESM. Species occurrence data were obtained from the literature and bioclimatic data were acquired from Bio-ORACLE. The modeling was performed by integrating the MaxEnt algorithm to R software. Significant differences between future and present environmental suitability for the seaweed cultivation were validated by applying the Friedman test. Our results revealed a significant increase in suitable areas for G. birdiae cultivation in the future, mainly in the coast of the Northeast and Southeast regions of Brazil. Our projection is consistent with the assumption that ocean warming will expand warmer water species to formerly colder regions. Temperature and salinity were not the most limiting factors for G. birdiae cultivation, whereas high nitrate concentrations may limit it. Our data revealed that environmental suitability areas for G. birdiae cultivation in Brazil will not be negatively affected by climate change. The seaweed G. birdiae shows a great potential for being cultivated in the Brazilian coast in the present and future, which could be a relevant source of income for coastal communities.