Distribution and Characterization of Threatened Common Eagle Ray Aggregations in the Central–Western Mediterranean Sea: Opportunities for Regional Conservation Actions

ABSTRACT

Many sharks and rays aggregate in critical habitats to migrate, rest, feed, mate or give birth. These predictable events, often involving dozens to thousands of individuals, represent important and vulnerable phases in their life cycles. However, fishing activities and unregulated tourism can threaten these aggregations, disrupting natural behaviours. Identifying when and where these events occur is essential to inform conservation strategies and spatial management. In this study, we combined a systematic literature review and social media data mining to investigate spatial and temporal aggregation patterns of the critically endangered common eagle ray ( Myliobatis aquila ) across the Mediterranean Sea. We identified seven aggregation sites and extracted biological indicators useful for their characterization. Additionally, we conducted a 4‐year underwater video survey at Marettimo Island (Italy), within the Egadi Islands Marine Protected Area, to describe a previously undocumented aggregation and assess potential impacts from underwater tourism. Up to 100 individuals were recorded together in summer months, with interannual site fidelity. Aggregations were mostly female dominated, with 4% of females observed pregnant. Courtship and mating behaviours were documented for the first time in this species. Our observations revealed a significant decline in eagle ray abundance in the presence of scuba divers, indicating potential disturbance from this human activity. This study provides critical insights into the aggregation pattern of a threatened species and highlights the need for management in high‐use coastal areas. We propose a set of biological indicators to support the identification and monitoring of eagle ray aggregation events, especially in data‐poor regions, offering a valuable tool for marine conservation planning.