Conservation through Research, Awareness and Education

UK Registered Charity Number: 1145387

Two giant black morph oceanic manta rays circle Roca Partida, a remote sea mount in the Revillagigedos Islands in Mexico.

Project Goals:

To identify local, regional and large-scale movements of oceanic manta rays in the Eastern Pacific and how these movements relate to manta population structure throughout the Indo-Pacific.

Why this is important:

Understanding how mantas travel through and utilise marine environments, how far ranging their populations are and where distinct, isolated populations exist provides insight into the best methods for protecting global manta populations.  By tracking oceanic manta movements and studying their population ecology, we hope to lay the framework for effective management strategies in the Indo-Pacific and worldwide.

Project Overview:

The Revillagigedos Islands of Mexico’s Pacific coast are perhaps one of the most famous locations for interactions with oceanic manta rays. Dr. Robert Rubin, Director of the Pacific Manta Research Group and a member of the Manta Trust Scientific Advisory Board, has been studying the mantas of the Revillagigedos Archipelago for over thirty years.

Two giant remoras hitchhike a ride on a feeding chevron morph oceanic manta ray.

The islands are now one of the last places along the west coast of the Americas where oceanic mantas can be seen regularly and in abundance.  Twenty years ago, manta interactions were common in the nearby Sea of Cortez, but after heavy fishing pressures in the ‘90s, mantas are now rarely seen in the region.  Due to the remoteness of the Revillagigedos Archipelago, the manta and shark populations here were largely spared by fishermen and in 1994 the islands were declared a  Biosphere Reserve, granting protection to the marine residents and visitors, as well as a number of endemic terrestrial species.

Working in conjunction with the Manta Trust, the Pacific Manta Research Group is studying the oceanic manta population of the Revillagigedos in an effort to better understand local, regional and large-scale movements of mantas in the Eastern Pacific and ultimately the Indo-Pacific as a whole.  Using photo-identification and acoustic tagging techniques, researchers are tracking oceanic mantas during their visits to the islands—showing how the mantas move between the three islands of the archipelago, where they spend most of their time and how long they stay. When the mantas leave the islands for open ocean satellite tagging is then used to show how far the mantas travel, where they go and what pelagic habitats they use most frequently.  The data gathered by satellite and acoustic telemetry give scientists an idea of how mantas are utilising different regions and habitats, what habitats are critical to their continued survival and how large their ranges are.  This information is essential in developing effective conservation and protection strategies at both the ecosystem and species level.

Shafts of sunlight pierce the water, illuminating the dorsal surface of a giant oceanic manta rays at a site known as the Boiler in the Revillagigedos Islands.

Main Objectives:

  1. Maintain a running, 30+ year photographic database of individual oceanic manta rays that visit the Revillagigedos Islands to better understand the region’s manta population.
  2. Use DNA analyses to determine the population structure of manta rays in the Eastern Pacific and Indo-Pacific as a whole.
  3.  Track localized movements of oceanic manta rays using acoustic telemetry to identify important habitats and spatial partitioning, or site usage, by individual mantas.
  4. Track large-scale movements of oceanic mantas using satellite telemetry to identify regional critical habitats and productivity hotspots, as well as manta migration patterns.
  5. Educate dive tourists on Liveaboard boats in the Revillagigedos Islands about manta ray biology and ecology and threats that global manta populations currently face.

 

© 2017 Manta Trust