Coastal breeding aggregations of threatened stingrays and guitarfish in the Levant

Abstract

Stingrays and guitarfish are globally threatened by overexploitation, particularly so in the Mediterranean Sea. Nevertheless, very little information is known about their ecology, behaviour, and taxonomy in the Mediterranean, and especially in the Levant, where water temperature, salinity, and the impact of invasive species are 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. Visual surveys were conducted, which allowed the documentation of stingrays and guitarfish behaviour, and which was not available from data based on fishery catches. The census took place within a marine protected area over a period of 3 years. Altogether, we documented 675 batoid observations. One of the observed species is Endangered (Glaucostegus cemiculus) and one is Vulnerable (Dasyatis pastinaca), whereas the others are classed as Least Concern (Torpedo torpedo and Torpedo marmorata), Data Deficient (Taeniurops grabatus), non‐assessed within the Mediterranean (Dasyatis chrysonota), and Not Evaluated (Himantura uarnak). Results show clear seasonal patterns, with dense aggregations recorded during spring and early summer, when densities reached 85 observations per kilometre. In addition, there were clear indications of breeding behaviour in D. pastinaca and D. chrysonota, including the first recorded 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 previously. This highlights the importance of conserving shallow habitats as potential breeding grounds. As these sites are easily reached while both snorkelling and diving, the aggregation of these charismatic species can serve as potential ecotourism sites. Finally, this study shows the benefits of using simple visual census, as opposed to catch‐based methods, to record both the diversity and the behaviour of batoids.

Integrating Literature, Biodiversity Databases, and Citizen-Science to Reconstruct the Checklist of Chondrichthyans in Cyprus (Eastern Mediterranean Sea)

“…Our data also confirm the findings of [49], who suggested that Cyprus should be considered a crucial area for the conservation of G. cemiculus, a species listed as critically endangered by the IUCN Red List and whose populations have drastically decreased all along the African coastline due to overfishing [51]. In addition to Cyprus, this taxon now only survives in few locations in the Mediterranean Sea, namely, the Gulf of Gabes [52], the Israel coast [53], and Iskenderun Bay [54]. In addition, we recorded a pregnant G. cemiculus, suggesting that members of this species nurse and potentially spawn in Cyprus; a specimen of A. bovinus observed on different days in Akrotiri Bay (south coast of Cyprus), suggesting site fidelity by this species; migration routes by M. mobular, with aggregations of large specimens occurring in late winter-early spring; and in general, spawning aggregations of stingrays (Dasyatis pastinaca and Bathytoshia lata), with pregnant females observed during spring and summer seasons.…”

The use of fishers’ Local Ecological Knowledge to reconstruct fish behavioural traits and fishers’ perception of conservation relevance of elasmobranchs in the Mediterranean Sea

“…Nonetheless, LEK suggests the occurrence of such aggregations in 4 GSAs (6,9,11,16), in close correspondence with the main Mediterranean distribution of the species (Follesa et al, 2020). Among Mediterranean batoids, aggregation records have been published only for D. pastinaca in the Levantine Sea (GSA 27) (Chaikin et al, 2020), but this species occurrence has been documented in other coastal areas of the central Mediterranean Sea (GSA 16, Tiralongo et al, 2020). This study highlighted two more GSAs (11 and 17) where D. pastinaca aggregations occur according to LEK.…”

“…Additionally, the incorporation of specific information on these aspects is essential for developing appropriate and effective management strategies (Jacoby et al, 2012;Chapman et al 2015;Braccini et al, 2016). While several studies in the Atlantic and Pacific Oceans have been performed on the social behaviours, movements and migration of elasmobranchs (see, for review, Jacoby et al, 2012;Braccini et al, 2016), very little information is currently available in the Mediterranean Sea (Abudaya et al, 2018;Barash et al, 2018;Chaikin et al, 2020).…”

Trends in sightings of the stingrays of southern Mozambique

“…Seasonal changes in elasmobranch abundance have been linked to reproductive behaviour, ontogenetic habitat shifts and changing abundances of prey and predator species (Chaikin et al 2020;Le Port et al 2012;Schlaff et al 2014). Megatrygon microps and T. meyeni, although sighted throughout the year, peak in abundance in opposite seasons, when they can be seen in groups of up to four and five individuals respectively.…”