19 Feb 2014
Conserving the World's Largest Population of Giant Manta Rays
The South East Pacific is home to the largest documented population of Manta Rays in the world, with over 650 individuals having been identified in Ecuador. Although protected in Ecuador, these rays are believed to migrate seasonally into Peru, where their presence is poorly studied, and they receive no protection at all.
In 2012, Planeta Océano started researching the occurrence of this highly vulnerable species in Peru, together with partners The Manta Trust and WildAid. By assessing landings and conducting on-board observations, we discovered that manta ray distribution in Peru coincides with 4 important fishery areas, leading to its bycatch and intentional capture.
Our study reported the capture of 7 manta rays (August 2012 - July 2013). Many of these were pregnant females, suggesting the existence of an important reproduction area in Peruvian waters. This photo shows one of the embryos unable to be born. Because of this species’ extremely slow reproductive rates – giving birth to one pup every two to five years on average after reaching maturity at ten or more years – its populations are unable to withstand continued fishery pressure.
In addition, four species of mobulas, closely related species of the Mobulidae family, are also harvested off the coast of Peru (Mobula japanica, Mobula thurstoni, Mobula munkiana, Mobula tarapacana). Although these are classified by the International Union for Conservation of Nature (IUCN) as either ‘Near Threatened’ or ‘Data Deficient’, over 95 tons of mobulas were landed in Peru (January - August 2013). The amount of landed individuals almost doubles the amount that is landed in Indonesia, a country well-known for its mobulid fisheries.
Of the captured mobulas, up to 60% of individuals of Mobula japanica and 100% of Mobula thurstoni were registered under the age of maturity. Presence of embryos observed in landings suggest that females had aborted with the stress of their capture.
Our extensive market surveys, thanks to support from the New England Aquarium, have revealed that mobulid meat in Peru is mainly used in typical dishes, such as “chinguirito” or “tortilla de raya”. To prepare these dishes, the meat is consumed dried and salted: a process that leads meat to lose 70% to 80 % of its weight in water, and that stimulates excessive harvest and exploitation.
Although these local dishes are common, artisanal fishermen earn an average of only US$0.33 per kilo of manta meat. Fishermen have confirmed that their monthly income depends little on these species, and that these are not reliable resources to encounter and harvest. Thus, many fishermen are thus supportive to protect and conserve them.
We are now working to promote alternate livelihoods that can promote manta conservation, while increasing fishermen income and enhancing sustainable development of local communities. With support from Project AWARE, we’re empowering 10 artisanal fishermen to offer ecotourism trips to observe manta rays in Peru. Current research expeditions with international volunteers are already being coordinated with fishermen.
Research and alternate livelihoods is coupled with education and outreach, to spread community awareness on manta ray conservation. To date, over 900 people have been reached through these efforts. In addition, with our findings, our team has presented a proposal for national protection of mobulids, which has received great interest from governmental authorities.
With these comprehensive efforts, we hope to contribute in creating the world’s first multinational, regional effort to protect these very vulnerable migratory species. Join us on Facebook in this mission!