eManta: Global Threats to Manta Rays
Have you ever realized that manta rays — the majestic black and white rays that are often features of nature documentaries — are targeted by fishers for their rays and gills (‘gill rakers’ to be exact)?
In the eManta project — Global Population Trends and Human Use Patterns of Manta and Mobula Rays — we evaluated the global threats to manta rays to understand the protections that they need.
*Tip: Do an internet search for “manta gill rakers” to see what we’re talking about!
**NOTE: When we began the project, there was only one named species. By the time we finished, there were three named species. And, shortly after publication, manta rays merged with Mobula rays, or devil rays. This shows how much we’re still learning about even the largest charismatic megafauna, imagine how little we know about the lesser known species.
Project Overview?
People love to dive with manta rays. Tourists fly around the world just to see them. So alarms rang when they started to disappear, and that’s when we were recruited to help.
Like sharks, manta rays reproduce very slowly and are vulnerable to overfishing.
Our eManta project was set up and solicited observations and insights from local, experts in 90 regions of the world.
This comprehensive effort aimed to understand the distribution and threats faced by Mobulidae and we gathered information from 200 to 62,000 dives per region.
Key Findings?
Mobulids, comprising eleven species, exhibit globally and regionally restricted distributions, congregating in specific hotspots with low sighting frequencies (<1% of dives).
Nearly half (47%) of the surveyed regions reported declining Mobulid sightings over the past decade, indicating the urgent need for conservation measures.
While Mobulid ecotourism is prevalent in many regions (45% reported), only 32% of these areas have some layers of protection, emphasizing the need for improved conservation policies.
Mobulids are being fished and sold in local markets in 16% and 12% of regions, respectively, particularly in areas adjacent to mobulid abundance hotspots and ecotourism regions.
With the exception of only two countries, fishing and selling of Mobulid rays is not being reported — this means that IUU fishing (illegal, unreported, unregulated fishing) combined with international trade is a threat.
Implications for Conservation?
Our findings underscore the urgent need for improved conservation and monitoring efforts.
Identifying regions where ecotourism and exploitation are in conflict can guide prioritized conservation actions.
The eManta project is also a beacon for participatory and citizen science, and the need for timely, ongoing, scalable research that keeps pace with business and exploitation.
Outcomes?
The discrepancy between the number of countries reporting catch Mobulid rays and those that were actually catching them, suggested widespread unreported and unregulated (IUU) fishing of mantas. This finding was pivotal for advocating for their listing on the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).