Mobulid Rays in the Philippines

Mobulids (family Mobulidae), commonly referred to as devil rays, are cartilaginous fishes found circumglobally in tropical, subtropical, and warm temperate waters. These pelagic species exhibit low fecundity and slow maturation; however, their life history remains poorly understood, yet these species are highly exploited worldwide. This family includes the genus Manta and the genus Mobula with 11 identified species. Five of these species have been confirmed in the Philippines, namely: the spine-tail devil ray (Mobula japanica), bent-fin devil ray (Mobula thurstoni), sickle-fin devil ray (Mobula tarapacana), the oceanic manta ray (Manta birostris) and the reef manta (Manta alfredi). Two other species the Pygmy Devilray (Mobula eregoodootenkee) and the shortfin devil ray (Mobula kuhlii) are thought to occur in Philippine waters though these sightings have not yet been officially confirmed.  

A school of Mobula japanica encountered by the team while on survey in the Bohol Sea.

A school of Mobula japanica encountered by the team while on survey in the Bohol Sea.

Studying a century-old mobulid fishery

One of our primary research sites has been the monitoring of a century-old ray fishery site in Bohol, with the goal of understanding the reproductive biology of the devil rays to assess the sustainability of the fishery. Our team has been working with the local fishing community since 2012.

Building a national photo-ID catalogue 

We are currently building a national photo-ID catalogue using submissions from citizen science as well as encounters photographed by our team in Tubbataha Reefs Natural Park and other opportunistic sightings in some of our other field sites. We are also working with MantaMatcher, to ensure mantas encountered in the Philippines are added to their international catalogue. 

Both reef and oceanic manta rays can be identified using the spot pattern on their ventral side (underbelly). This patter is unique to each individual and can give us insight to their movements when encountered in different locations. 
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A reef manta fitted with an acoustic tag in Tubbataha Reefs Natural Park.

A reef manta fitted with an acoustic tag in Tubbataha Reefs Natural Park.

Tubbataha Reefs Natural Park

In 2015 LAMAVE started a collaborative project with the Tubbataha Reefs Natural Park to assess the abundance and diversity of rays within the park. Using BRUV systems and visual identification a number of different species have been reported in the park including: Porcupine, marble, cowtail, whiptail, Mobula and manta rays.  Recently we started a tagging project, using acoustic tags to determine the local movements of reef mantas around the atolls.