The government of Mexico added 10 species of parrotfish to its national registry of protected species in October.

In a letter to the government, the environmental NGO AIDA argued that parrotfish and other herbivorous fish, whose numbers have been declining due to fishing, are necessary to maintain the health of coral reefs.

AIDA has embarked on a three-year project to work with policymakers to protect herbivorous fish in Mexico and five other Latin American countries.

Mexico protected 10 species of parrotfish in October, a move that conservationists say will help the country’s coral reefs recover, in addition to safeguarding the species’ numbers.

“It’s really good news for Mexico,” María José González-Bernat, a marine biologist and scientific adviser to the Interamerican Association for Environmental Defense, said in an interview.

Known by the acronym for its name in Spanish, AIDA backed a proposal to the Mexican government from the Healthy Reefs Initiative to codify the legal protection of these 10 species, which argued that they are critical to robust and resilient coral reefs. The group has also launched a three-year project to shore up populations of parrotfish and other plant-eating fish that live in the waters off Mexico and five other Latin American countries.

The health of many of the coral reefs in these places has declined, González-Bernat said, and AIDA believes that safeguarding herbivorous fish is crucial to allowing coral-anchored ecosystems to come back. They graze on the algae that, left unchecked, can blanket reefs and choke off corals’ supply of oxygen and light. These algae inhibit corals’ growth and their ability to withstand the damaging effects of climate change, such as bleaching.

Until recently, parrotfish and other herbivores weren’t traditionally high on the list of fishers’ preferred catch, but that’s changed as overfishing has driven commercial species into decline, González-Bernat said.

“The numbers of other species have come down, so [small-scale fishers] need an alternative,” she said.

Parrotfish also hang out around the rocks on the reef, she said, making them easy quarry for harpoon- and net-bearing fishers.

The protections in Mexico are just the first step, González-Bernat said. AIDA’s Reef Fish Conservation project aims to work with leaders in Colombia, Costa Rica, Guatemala, Honduras and Panama, along with Mexico, to encourage international treaties and regulations that protect these fish and their spawning grounds. Funded in part by the philanthropic organization Oceans 5 for this project, AIDA plans to work with other groups, such as the Health Reefs Initiative, to backstop their arguments for fish protections with sound data.

Bringing multiple countries into alignment on these issues won’t be easy, González-Bernat said, but the group knows that they need to focus on more than a single country to protect these fish populations and their reef habitats.

“There are no borders when it comes to the ocean,” she said.

“It’s not impossible, but it’s hard,” she added, noting that the international strategy is essential to the broader goal of the project. “We’re really trying to protect coral reefs as a very big and important ecosystem in the ocean.”

Banner image of a stoplight parrotfish (Sparisoma viride) by Adona9 via Wikimedia Commons (CC 3.0).

John Cannon is a Mongabay staff writer based in the Middle East. Find him on Twitter: @johnccannon

Correction: An earlier version of this article misidentified the parrotfish in the final photo. It is a stoplight parrotfish, not a rainbow parrotfish.

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