Importance of Mangrove Shorelines for Rainbow Parrotfish Scarus guacamaia: Habitat Suitability Modeling in a Subtropical Bay

Rainbow parrotfish Scarus guacamaia is a coral-reef herbivore that requires both mangrove and coral-reef habitat to complete its life cycle. This species is listed as ‘vulnerable’ by the International Union for Conservation of Nature. The present study used a long-term visual survey of mangrove fishes to develop a predictive habitat model for juvenile S. guacamaia . The factors tested were temperature, dissolved oxygen, salinity, average depth, distance from offshore channel openings, temperature variation (Δ T ), and salinity variation (Δ S ). The average depth, distance from offshore channel openings, Δ T , and Δ S emerged as significant within the model evaluations. The results suggested that high variation in salinity reduces mangrove habitat suitability for this species. Salinity variation along many of south Florida’s coastal bays is largely driven by water management-related freshwater canal discharges. Everglades restoration efforts seek to reduce Δ S along south Florida’s mainland shoreline; thus, if successful, restoration may also confer benefits to Scarus guacamaia through the subsequent expansion of suitable mangrove habitat.