MANILA, Philippines — A collaborative study led by the Large Marine Vertebrates Research Institute Philippines (LAMAVE) has identified four hotspots for manta rays in the Philippine after compiling national population database.
LAMAVE, partner organizations, and public searches led to the analysis of 2,659 manta ray sightings across 22 different sites in the Philippines; these account for two species, reef manta and oceanic manta, with both kinds found in 11 of the 22 locations.
Of the 22, four were identified as hotspots for manta rays:
- Ticao-Burias Pass Protected Seascape in Bicol
- Tubbataha Reefs Natural Park
- Puerto Princesa City
- Municipality of Taytay
The four accounted for 89% of all individual manta rays, where specific behaviors were observed including cleaning, courtship, and feeding.
The study also found that several oceanic mantas kept returning to areas where they were sighted. One female manta was sighted in Daanbantayan, Cebu in 2009, then later near Tubbataha in 2014, and back in Daanbantayan three years later.
The longest interval for resightings in Daanbantayan were for two manta rays in an eight-year interval, while six other individuals were sighted again in at least two other different years.
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Between 2004 and 2020, 392 individual sightings of reef mantas were recorded, and over 90% of them were in the Ticao-Burias Pass, Taytay, and Tubbataha.
Additionally, around 66 to 80% of these mantas were sighted more than once at cleaning stations — small patches of coral that house cleaning fish.
The research points out that both species of manta are under threat, as seen in a quarter of the Ticao-Burias Pass and Taytay sightings having fishery-related injuries (damaged or missing fins, severe cuts).
Damage to cleaning stations — fishing gear getting entangled in the reef resulting in destruction — have also been identified as a concern.
Furthermore, Daanbantayan sightings of oceanic mantas dropped from 73 sightings between 2006-2012 to just 16 in the next six years despite increased diving efforts; the Ticao-Burias Pass similarly saw a drop from 15 sightings between 2013-2014 to only three between 2017-2019.
LAMAVE noted that oceanic mantas have a population recovery time of more than 37 years, making the protection of remaining individuals a crucial act for species recovery.
The organization also suggested conservation strategies like marine protected areas and fishing gear regulations should be urgently adopted at the four manta ray hotspots.
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