ABSTRACT: This study aimed to determining the manner in which salinity influenced growth of macroalgae Gracilaria birdiae, with objective identifying its tolerance limits this abiotic variable. The specimens were submitted nutrient-enriched water varying salinities (0, 10, 20, 30, 40, 50, and 60 ppt) for a 30-day period. Initially, under extreme conditions (0 G. birdiae suffered negative impact...