We’ve spoken a couple times this week about how little is known about manta ray populations throughout the globe. On today’s episode of Research Thursday, we decided to focus on a study concerning the regional movement patterns of the reef manta ray, Manta alfredi, throughout the waters of Indonesia. This smaller species of manta ray is ecologically and economically important to the island nation, making it all the more important that we have some understanding of the reef manta ray’s movement patterns.
Elitza Germanov and Dr. Andrea Marshall, authors of the study “Running the Gauntlet: Regional Movement Patterns of Manta alfredi through a Complex of Parks and Fisheries” and members of the Marine Megafauna Foundation, sought to track reef manta rays throughout a small subsection of the Indo-Pacific. Using an online database called Manta Matcher, they were able to compare and analyze 2,604 photos of Manta alfredi individuals collected by divers over a nine-year period. The authors found that although these rays migrate between at least three protected sanctuaries, they cross large expanses of heavily trafficked and unprotected areas of the ocean in the process.
Manta rays do face natural predation, but the majority of reported deaths are due to entanglement by fishing gear, hunting, or other events caused by humans. This study shows that protecting isolated patches of ocean, though certainly beneficial, does not always ensure that its highly migratory residents are in fact protected. More and more researchers and conservationists are calling for ecologically-connected sanctuaries, those that protect the entire ecosystem or geographic range of a given population. In countries like Indonesia, where these reef mantas play a huge role in their ecotourism community, it’s vital that these populations aren’t subjected to heavy fishing pressures while they travel between sanctuaries.
Enjoy the Podcast!