Years ago, on the Gulf of California, Palacios began implanting small acoustic devices in rays that transform them into data messengers. Fishermen, hired for the task, capture the animals and then return them to the water. This strategy is known as passive acoustic telemetry, and although seemingly invasive, is carried out with extreme care. Once released, the animals resume their swim.
Each time a tagged animal passes near an underwater receiver, the date and duration of its visit is recorded. With this data, in 2021 Palacio was able to describe for the first time a breeding area of M. munkiana in a bay in the Gulf of California. To further reconstruct the life history of these creatures, the scientist collects testimonies from fishermen and observes their monumental groups using drones.
Palacios sleeps little these days. He spends his nights watching the fishermen of bottom-spotted stingrays, a commercial and legally fished species in Mexico, as they cast their nets into the sea. In those nets, mobulas are caught incidentally. One experiment of his consisted of more than 40 nights documenting the situation and assessing whether the use of lighter nets could reduce bycatch.
A Lack of Strict Protection
Because of their supposed medicinal properties, the meat and gill plates of mobulas are increasingly in demand in Asia. Palacios recently led a study to try to understand the magnitude of the problem, which involved 100 surveys and interviews in 19 countries. The research team analyzed data from 75 nations, including photos and records of seizures in Palestine, Somalia, Vietnam, and Hong Kong.
The study revealed that meat is exported from countries such as Bangladesh (to mainland China, India, and Myanmar), Ecuador (to Peru), India, Madagascar, Madagascar, Mauritania, Myanmar (to Thailand), Oman (to United Arab Emirates), Senegal, United Arab Emirates, and Yemen. The highest prices for dried meat—up to $10/kg—were found in Bangladesh and Myanmar, while fresh meat reached $8/kg in Benin, Mexico, Brazil, and the Republic of Congo, with M. mobular and M. alfredi being the most hunted species.
Gill plates are harvested in 14 countries across Africa and Asia, and are imported mainly to mainland China and Hong Kong, where a kilogram can cost $1,260. They also reach Singapore, South Korea, and Thailand.
The researchers also found that although international mobula trade involves 20 countries, only five reported it to CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Since 2013, CITES has allowed regulated trade of mobulas in an effort to prevent their extinction, but trafficking of these animals’ meat and parts has not decreased. Some researchers therefore recommend moving to a full prohibition of trade.
Habitat care is also weak. UN biodiversity targets have called for nations to designate 30 percent of their waters as marine protected areas (MPAs) by 2030. While MPAs have increased dramatically in size over the past 15 years, currently only 16 percent of marine habitats critical to sharks and rays fall inside an MPA, and only 7 percent of these habitats are “no take” zones, where fishing is completely banned.
This story originally appeared on WIRED en Español and has been translated from Spanish.
