Stability and spatial variance of Mobula yarae-associated fish aggregates in South Florida

Abstract

Despite their importance to organismal and ecosystem function, symbiotic associations in marine environments are often poorly understood. In the case of manta rays, casual and temporary associations with fish and other hitchhiker species have been documented, but the extent of these interactions and their stability over time remain largely unknown. Here we examined nine years (2016–2024) of Mobula yarae visual survey data collected by freedivers in south Florida. A total of 465 manta ray encounters were analyzed to assess individual identification, symbiont community composition, and abundance. A subset of 213 videos captured between 2022 and 2024 were further analyzed for symbiont species spatial position relative to their hosts. Manta-associated fish aggregates were composed of four groups of teleosts (Echeneidae spp., Rachycentridae spp., Decapterus spp., and non-Decapterus Carangidae spp.) and manta rays were most frequently associated with fish in the family Echeneidae. Teleost symbionts differed in where they were most likely to be seen on their manta host by species, but overall, symbionts were most often associated with the ventral side of their hosts in the posterior righthand quadrant of the manta’s body. Studying manta-associated fish aggregates and symbiont community structure provides insight into the broader role manta rays may play in their environments and the need for consideration of species interactions in effective conservation and management.