The giant manta ray has become the first manta species to be listed as Endangered. The threat level to Mobula birostris has just been raised from Vulnerable on the IUCN Red List of Threatened Species.
The Endangered listing, which covers some 16,000 species, is reserved for those that cause grave conservation concerns. Almost a third of sharks and rays are under threat of extinction.
Mantas are now heavily targeted for their gill-plates for use in Asian “medicine”, and the Marine Megafauna Foundation (MMF) says this unsustainable trade is having a greater impact on giant or oceanic mantas than on other manta species.
“The giant manta ray is a classic example of a species that is quickly succumbing to human-induced pressures,” commented MMF co-founder Dr Andrea Marshall, who was first to identify Manta birostris as a separate species and have it recognised as such in 2009. She was also lead author of the IUCN’s new assessment.
“When we first assessed manta rays in 2003 there simply was not enough information on the species to determine their conservation status and they were listed as ‘Data Deficient’,” she says. “But on each of the subsequent assessments, their conservation status increased steadily from Near-Threatened to Vulnerable and now to Endangered.”
Listing under two major international conservation treaties, CMS in 2011 and CITES in 2013, appears to have achieved little in arresting the species’ decline.
Late to reach sexual maturity, the rays give birth only to single offspring every few years, and do little to protect them, so their reproduction rate is too slow to build back depleted numbers. “Manta rays simply cannot withstand such pressures on their populations,” says Dr Marshall.
The only faint hope for giant mantas appears to be through their economic value as living creatures. “Interactions with manta rays are highly sought after by dive and snorkel tourists globally and contribute millions of dollars to tourism economies each year, particularly in developing nations,” says MMF senior scientist Dr Stephanie Venables.
“At this pivotal time, recognising their economic value may help to encourage the protection of this enigmatic and now endangered species”