Novel insights into coastal site affinity and habitat connectivity of a benthic stingray with implications for management

The blue stingray Dasyatis chrysonota is an important and endemic coastal inhabitant of southern African coastal waters however, it is listed as Near Threatened with declining populations. Understanding it's spatial ecology in the context of current Marine Protected Areas (MPAs) is vital to not only inform population dynamics and ecological roles, but to determine whether currently zoned MPAs can provide sufficient protection to this species. Twenty-seven individuals were monitored using the Acoustic Tracking Array Platform (ATAP-a nation-wide collaborative network of acoustic receivers) for up to 4.5 years. Individuals displayed site affinity to defined regions of the coast, with the majority of detections for most individuals being recorded in the shallow bay/coastal shelf they were tagged in. However, important movement corridors linking different habitats were also identified (inshore vs offshore and coastal bay vs coastal shelf habitats). This habitat use varied monthly and was influenced by temperature, with individuals displaying restricted movements to the shallow bay habitat in summer when deeper waters were much colder. The large collaborative nature of the ATAP allowed for the monitoring of a benthic ray across large spatial scales for the first time, challenging preconceived notions that small undulatory batoids cannot travel large distances (many individuals were found to travel up to 200 km). Insights can also assist in local management of this species, and highlight that current MPA zonation may not be sufficient to protect blue stingrays from further population declines.

Automated summary

The blue stingray is an important and endemic species in southern African coastal waters but is currently facing population declines. A study using acoustic tracking revealed that the species displayed site affinity and movement corridors between different habitats. The findings highlight the importance of understanding the species' spatial ecology in the context of Marine Protected Areas for effective conservation.