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UN unanimously approves proposal to list the largest living ray on CMS

Bergen, Norway Nov 25th 2011: Convention of Migratory Species of Wild Animals.

Focal points from around the world meet to vote on a proposal put forward by the Ecuadorian Government to protect the world’s largest ray, the giant manta ray Manta birostris. Manta rays, which were only recognized as two distinct species in 2009, were listed as globally threatened species in 2011 for the first time by experts from the IUCN Shark Specialist Group in recognition of the increased threat they face around the world.

Manta rays, which are worth an estimated US$100 million annually in the marine tourism industry, are already protected in nine Range States. However, previously they have had no protection outside these areas. Giant manta rays regularly migrate into the open ocean where they are killed by fishers after their gill rakers, which have become valuable in Chinese medicine.

Recent research headed by Dr. Andrea Marshall, president of the Marine Megafauna Association and lead author of the IUCN Red List conservation assessment for manta rays, has shown that giant manta rays migrate over 1000 km and can dive to over 1 km deep.

“Giant manta rays are a true international species. They ignore political boundaries and will happily swim into deep oceanic waters,” said Dr. Marshall. “Manta rays, in general, are long-lived, and only have one offspring every one to five years. Unregulated fisheries can quickly wipe out entire populations”

This recent listing obligates CMS member countries to provide strict national protections for giant manta rays and their key habitats. The listing also promotes regional conservation action amongst all Range States, many of which have directed fisheries currently operating within their boarders.

The Marine Megafauna Association, which has been critically involved in the proposal process for Manta birostris, commend the action taken by CMS parties on Friday and urges swift, formal action throughout the respective Range States. 

“This could not have come at a better time,” said Dr. Marshall. “Manta rays worldwide face significant threats, but there has been tremendous support and momentum for their conservation recently. CMS listing is a major step toward our shared goal of global protection.” 

Summary of Pertinent Information on Manta birostris 


Manta rays rate amongst the least fecund of all shark and ray species, with litter sizes consisting of a single pup, long 12- month gestation periods and reproductive periodicity ranging from 1-5 years in the wild. The conservative nature of their life history suggests a very low intrinsic rate of population increase, which limits their ability to recover from human induced threats. 

Distribution & Populations 

Giant mantas are widely distributed through the Atlantic, Indian and Pacific oceans in both coastal and offshore areas. Insufficient data exist to estimate global population  size for Manta birostris, but regional populations are generally small, with less than 350 individuals ever documented from a single aggregation site. Individuals show a degree of seasonal site fidelity to some critical habitats but the species largely appear to be transient.

Habitat & Behaviour

Giant manta rays occur in tropical, sub-tropical and temperate waters. This species appears to be largely oceanic and is often sighted in offshore habitats or inshore areas in close proximity to deep water. While they are most commonly encountered in surface waters, preliminary findings by researchers at the Marine Megafauna Association suggest that this species spends a significant proportion of time in deep water and are capable of dives to over 1,000 meters. Recent, satellite tracking results from the Marine Megafauna Association have revealed that M. birostris are capable of long migrations (over 1,000 km) and cross national borders, traverse large bodies of water and commonly move into international waters. 

Direct threats to populations

At present, most target Manta fisheries are directed towards Manta birostris. As an oceanic species, giant manta rays are vulnerable to capture in large-scale fisheries that are operating along continental shelves, in major waterways, or in international waters. Due to their migratory nature, concerns exist for national management strategies of M. birostris, which only provide protection when individuals visit their waters. 

The main threat to giant mantas is fishing, whether target or incidental. Manta rays are currently killed or captured by a variety of methods including harpooning, netting and trawling. These rays are easy to target because of their large size, slow swimming speed, aggregative behavior, predictable habitat use, and lack of human avoidance. Targeting giant mantas at critical habitats or aggregation sites, where individuals can be caught in large numbers in a short time frame, is also of particular concern.

Manta species have a high value in international trade, particularly their gill rakers which are used in Asian medicinal products. This market has led to directed fisheries for manta rays, which are targeting these rays in unsustainable numbers. Artisanal fisheries also target this species for local products. Aside from directed fisheries, manta rays are also taken as by-catch in everything from large-scale fisheries to bather protection nets. As a result of sustained pressure from fishing (both directed and by-catch) certain monitored sub-populations appear to have been rapidly depleted.

Note to Editors:

CMS is an intergovernmental treaty formed under the United Nations Environment Program. Conferences of the CMS Parties take place only every three years. The November 25th decision marks the first international agreement to protect the giant manta ray.

Manta birostris is the first ray ever to be listed on CMS and is also one of the only shark or ray species to have been approved for both Appendix I and Appendix II level protection.

CMS Appendix I, reserved for species that are threatened with extinction, obligates CMS Parties (currently numbering 116) to strictly protect the animals, conserve and restore their habitats, mitigate obstacles to their migration, and control other factors that might endanger them. CMS Appendix II includes migratory species that would significantly benefit from international co- operation for which CMS encourages global and/or regional agreements and concerted action.

To date, manta rays are only formally protected in New Zealand, Ecuador, the USA (Florida, Hawaii, Flower Garden Banks), Guam, Maldives, Yap, Indonesia (Raja Ampat), the Philippines and Mexico. 

The  Manta  birostris  listing  was  proposed  by  Ecuador.  The  European  Union,  Senegal, Madagascar, Australia, United States, Chile, Mozambique, and Uruguay took the floor to convey their support for the proposal. The host country, Norway, also voiced support and suggested that the reef manta ray (Manta alfredi) be listed at the next Conference of the Parties, in 2014.

Conservation groups actively supporting the manta ray proposal included: the Marine Megafauna Association, Shark Advocates International, The Ocean Foundation, Mantas Ecuador, Humane Society International, The Norwegian Shark Alliance, Project AWARE Foundation, Wildlife Conservation Society, and Shark Trust.

For more information on manta rays see: 

Marshall, A., Bennett, M.B., Kodja, G., Hinojosa-Alvarez, S., Galvan-Magana, F., Harding, M., Stevens, G. & Kashiwagi, T. 2011. Manta birostris. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <>.

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