An Atlantic cownose ray (Rhinoptera bonasus). Credit: Cecilia Hampton, FAU Harbor Branch
Key points:
- Researchers combined citizen science, photographs, and morphological and genetic data to show that the Atlantic cownose ray has recently made a new home in Bermuda.
- Dramatic oceanography changes in the North Atlantic Ocean likely shifted the rays’ range to Bermuda.
- The team hopes to track cownose rays’ reproductive success and interactions with other ray species in the region.
For hundreds of years, the whitespotted eagle ray was considered the only inshore stingray species in Bermuda – a group of oceanic islands and circular-like coral reefs. But now, in a study published in Frontiers in Fish Science, scientists have found evidence that the Atlantic cownose ray has joined the eagle ray and made a new home in Bermuda.
Researchers compiled communications with fisheries officers and staff, photographs from local citizen-scientists, and on-water observations and collections. They then combined these findings with extracted DNA from tissue samples of five individual cownose rays between 2021 and 2022.
With their extensive data, the team confirmed the presence of the cownose ray species and demonstrated that they had a novel migration to Bermuda. Researchers have not yet determined if the species is a full-time resident or a seasonal visitor, but their findings suggest that the rays have been in Bermuda for more than a decade.
To determine what triggered the outmigration of cownose rays along the Atlantic coast, researchers investigated sea surface temperature, timing, and oceanography. During the period that researchers examined, the North Atlantic Ocean experienced a southward shift in westerly winds that influenced current dynamics in the region.
“This climatological anomaly and associated oceanographic changes may have played a similar role in shifting cownose rays eastward from their established range to Bermuda,” explained study author Matt Ajemian, professor at Florida Atlantic University Harbor Branch.
In the future, the research team hopes to use systematic aerial surveys and monitoring to track reproductive success of the cownose ray population in Bermuda. They also want to examine if the species interacts or even competes with other ray species in the region.
“We need more research into the potential mechanisms that facilitated the arrival of cownose rays to Bermuda, as this could reveal whether additional introductions of this species and others are possible in the future,” said Ajemian.