Background

The International Union for the Conservation of Nature (IUCN) currently lists manta rays (Manta birostris) as ‘near threatened’. It’s known that several populations around the world are severely depleted, but not enough scientific work has been carried out to properly assess the species as a whole. Almost nothing is known about their population ecology, use of critical habitat, movements or reproduction, all of which are vital in order to accurately assess the state of the species.

Manta rays are the largest of over 500 different species of rays and skates; their triangular pectoral fins can span almost 8m in width and weight reach over 2,000kg. Andrea has developed a systematic method of identifying individual mantas by their ventral (underside) spot patterns, which are unchanging and present from birth. This has allowed her to establish an identification database based on a single reef site in Mozambique which now contains over 900 individuals, making it the largest and most in-depth manta dataset in the world. When combined with population modeling and behavioural observations, her data suggests that southern Mozambique may host the largest manta population in the world, with possibly 1000 individuals in the area Andrea works in alone.

Acoustic tagging equipment and listening stations sponsored by SOSF have enabled Andrea to examine how individual manta rays use critical habitats, like cleaning stations, along the coastline. Andrea and her group have also begun the genetic sampling of the entire local manta population. Cutting edge genetic research in conjunction with researchers at the University of Queensland is also being planned; in a first of its kind, its focus will be on the relatedness within the local manta population. With the continued assistance of SOSF, Andrea is also conducting comparative research by collecting DNA samples in Mexico, Japan, Yap, Thailand, Indonesia and Australia.

Aims and Objectives

• Properly classify the different species of manta ray.
• Show how the habitats of the different species differ and overlap.
• Inform conservation strategies around the world to better conserve the different species.