Manta rays are enormous filter feeders that glide through tropical and subtropical waters worldwide. These charismatic animals, often called the gentle giants of the ocean, feed primarily on zooplankton, performing a crucial role in marine ecosystems. The question of whether these creatures are at risk depends on which of the two recognized species is being considered. Understanding their current status and the forces driving population decline is urgent due to their importance to ocean health and the global economy.
The Two Species and Their Current Conservation Status
The conservation status of manta rays is separated between the two distinct species: the Oceanic Manta Ray (Mobula birostris) and the Reef Manta Ray (Mobula alfredi).
According to the International Union for Conservation of Nature (IUCN) Red List, the Oceanic Manta Ray is listed as Endangered. This designation reflects significant population declines across its vast, open-ocean range, making it difficult to monitor and protect across international waters.
Conversely, the Reef Manta Ray is classified as Vulnerable. This species remains in more localized, shallower coastal habitats, allowing for easier monitoring and local protections. However, its proximity to shore makes it more susceptible to human pressures, such as habitat degradation and pollution. Both species are highly susceptible to threats because of their extremely slow life history traits, including late maturation and producing only one pup every one to five years.
Primary Threats Driving Population Decline
The greatest threat driving population decline is targeted fishing for their gill plates, also known as gill rakers. These feathery structures are highly sought after for use in certain Asian traditional medicine markets. This demand has created a high-value international trade that fuels legal and illegal fisheries, particularly in the Indo-Pacific. The lucrative market for gill rakers often outweighs the incentive for conservation, despite a lack of scientific evidence supporting their medicinal use.
Manta rays are also highly susceptible to incidental capture, or bycatch, in large-scale commercial fishing operations. Their large size and slow swimming speed make them vulnerable to entanglement in nets, longlines, and industrial fisheries intended for other marine species. Bycatch mortality is significant, especially for the pelagic Oceanic Manta Ray.
Furthermore, as filter feeders, both species are threatened by marine pollution, particularly the ingestion of microplastics. These tiny plastic particles mimic plankton, potentially causing internal injury, blocking nutrient absorption, and leaching harmful chemicals into the rays’ tissues.
Global Conservation and Protection Efforts
International treaties provide a foundation for global protection, most notably through the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Both manta ray species are listed under CITES Appendix II, which mandates that international trade in their parts, including gill plates, must be strictly regulated to ensure it is sustainable and does not threaten their survival. This listing, adopted in 2013, aims to reduce the economic incentive for the targeted fishing that has devastated populations.
At a local level, the establishment of Marine Protected Areas (MPAs) and sanctuaries offers a more direct line of defense. Countries like Indonesia and Ecuador have declared large swaths of their exclusive economic zones as manta ray sanctuaries, effectively banning fishing for them. Ecuador’s waters, for example, are home to one of the largest known populations of Oceanic Manta Rays, making localized protection measures especially impactful.
A growing economic argument for protection comes from responsible manta ray ecotourism, which provides a sustainable alternative to extractive fishing. A single live manta ray can generate millions of dollars in tourism revenue over its lifetime, far exceeding the one-time value of its gill plates. In contrast, a 2013 study estimated that the global direct revenue from manta ray watching tourism was approximately $73 million annually, with a total economic impact of $140 million, highlighting the financial benefits of keeping these animals alive. This economic shift incentivizes local communities to become active stewards of manta ray conservation.