Mobula tarapacana and their remora hitchhikers from a Mid-Atlantic aggregation.
Supervisor: Jorge Fontes (Univ. Azores)
Mobulids are often sighted in association with different hitchhiker fish species. Remoras have been identified as the most common hitchhiker for most mobulids species. They attach themselves to their host using a modified dorsal fin that acts as a suction cup. The remora receives protection from predation, enhanced foraging opportunities, increased encounters with conspecifics, and locomotor efficiency. What is still unclear is whether mobulids receive a significant return in benefits. Underlying patterns of symbiotic associations in mobulids have only started to be addressed and there is currently no data available for Mobula tarapacana. The present study substantiates M. tarapacana as a host for Remora remora and confirms this ecological relationship at seasonal aggregation sites at the Azores archipelago. We have demonstrated that remoras preferentially adhere to specific regions on M. tarapacana, both dorsal and ventral. Our study provides novel baseline information about the size distribution of remoras and their host and the remora load and distribution in the host. Using computational fluid dynamic analysis we were able to show that remora attachment was specific to regions with reduced frictional drag, which was even more stressed in smaller individuals. Further computational fluid dynamic studies aiming to assess the energetic cost or parasitic drag associated to the transport of remoras by mobulas should provide useful insights into potential biomimetic strategies to support the design of low drag/impact animal born biotelemetry tags.