The government of Peru has passed a resolution that bans fishing of giant manta rays in its waters and requires fishermen to release any accidentally caught mantas immediately back into the ocean. Peru joins a dozen other countries with manta protection laws, including its northern neighbor, Ecuador; between them, Peruvian and Ecuadorian waters hold the largest known population of the species in the world.

The move follows years of efforts by environmental organizations such as Planeta Océano, WildAid and The Manta Trust to advocate for the species’ protection and also promotemanta tourism, and comes eight months after Peruvian fishermen caught a 1-ton manta with a wingspan of 23 feet.

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Found mostly in tropical and subtropical waters around the world, giant mantas are especially vulnerable to over-exploitation because of their low reproductive rate: They produce one pup on average every two to five years. They are declining throughout their range not just because of accidental capture in nets but also as a result of targeted fishing for their meat and for their gill plates, which filter out plankton as they swim and which are sold in China as a culinary delicacy and a medicinal cure-all.

In the words of a recent article in the New York Times, retailers there “claim that the gills are a time-tested panacea for modern ills, that they can increase the amount of breast milk, detoxify the blood, cure chickenpox, heal tonsillitis and clear a smoker’s lungs.”

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WildAid estimates that the Chinese trade in manta gill plates is worth up to $30 million a year, and has found that it more than doubled between 2010 and 2013, likely in response to declining availability of large shark fins. However, a WildAid campaign may be nudging China toward adopting a ban on the gill trade, reports the NYT.

In the meantime, countries such as Peru are taking steps to protect the mantas in their waters — and, while lamenting that the new ban does not also cover the similarly threatened mobula rays, the Peruvian move has been warmly welcomed by the organization’s CEO, Peter Knights.

“Manta rays reproduce very, very slowly, and can be impacted by even limited fishing,” he said. “Peru’s new level of protection is vital to their survival and paves the way for the development of a sustainable manta ray tourism industry, which globally generates $140 million every year.”