Manta Sandy — 2024-12-18 — guide log
Depth: 12m | Time In: 09:15 WIT | Time Out: 10:02 WIT | Conditions: Mild southerly current, 30m visibility, 29°C
The objective was to log cleaning behavior for my ongoing study of Mobula alfredi social dynamics. We positioned our four-person group on the sandy bottom, 15 meters from the primary coral bommie that serves as the cleaning station. Within five minutes, the first reef manta, a large female with a distinctive propeller scar on her left cephalic lobe, arrived. She initiated a cleaning sequence with a group of bluestreak cleaner wrasse (Labroides dimidiatus), hovering motionless for 12 minutes. Over the 47-minute observation period, we documented five separate individuals, three females and two males, using the station. We noted a clear hierarchy; the larger females commanded longer, uninterrupted cleaning sessions, while the smaller males performed quicker passes. The mild current seemed to aid their ability to remain stationary with minimal effort. An interesting observation occurred at 09:48, when a juvenile male attempted to approach the station while the scarred female was present. She responded with a slight pectoral fin flick, a clear signal that caused the male to divert his path. This subtle, non-aggressive assertion of dominance is a key data point for our research.











