Coastal breeding aggregations of threatened stingrays and guitarfish in the Levant

Stingrays and guitarfish are globally threatened by overexploitation, particularly so in the Mediterranean Sea. Nevertheless, very little information is known about their ecology, behavior, and taxonomy in the Mediterranean, and especially in the Levant where water temperature, salinity, and the impact of invasive species is relatively high.

Although it has been suggested that some species may aggregate in the Levant, this has not been formally documented and the scale of this phenomenon, the taxonomic composition, and the temporal dynamics are unknown.  We conducted visual surveys, which allow the documentation of stingrays and guitarfish behavior and differ from most available data based on fishery catches. The census took place within a marine protected area over a total period of three years.

Altogether, we documented 675 batoid observations. One of the observed species is endangered (Glaucostegus cemiculus), one is vulnerable (Dasyatis pastinaca), while others are either least concern (Torpedo torpedo, Torpedo marmorata), data deficient (Taeniurops grabatus), or non-assessed within the Mediterranean (Dasyatis chrysonota), and not evaluated (Himantura uarnak). Results show clear seasonal patterns, with dense observations during spring and early summer, where densities reached 85 observations per kilometer. In addition, we found clear indications of breeding behavior in D. pastinaca and D. chrysonota. We also recorded the first documentation of D. pastinaca courtship in the Mediterranean.

Large seasonal stingrays and guitarfish aggregations in shallow waters have not, to our knowledge, been documented in the Mediterranean Sea. This stresses the importance of conserving shallow habitats as potential breeding grounds. As these sites are easily reached using both snorkeling and diving, the aggregation of these charismatic species can serve as potential ecotourism sites. Finally, this study shows the benefits of using a simple visual census, as opposed to catch-based methods, to record both the diversity and behavior of batoids.

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Batoid monitor report -2023