Manta Rays: Introduction

Manta Rays: Introduction

The word ‘Manta’ comes from the Spanish for cloak or shawl and refers to the two known species of manta – Manta Birostris – or giant oceanic manta, and the smaller, recently classified Manta Alfredi, often called the resident reef manta. They are found all around the world, with each species occupying their own ecological niche, although there are many crossovers between the two species habitat range.

Oceanic mantas have a wider geographical range and are known to be more migratory in nature; they are found in tropical, sub-tropical and temperate waters, often in the vicinity of productive coastlines with regular upwellings, oceanic island group and offshore seamounts. They have been sighted as far north as the coast of South Carolina in the USA, and as far south as New Zealand in the Southern Hemisphere.

The smaller reef manta, only recently described as a separate species in 2009, is found in inshore areas, around coral reeds, tropical island groups, atoll and bays, and along productive coast lines, like it’s larger counterpart. They have been termed resident or reef mantas to coincide with their preference for tropical waters with much smaller home range.

Manta rays are a cartilaginous elasmobranch fish, meaning that unlike the teleosts, or bony fish, they have a skeleton made entirely of cartilage; they first appeared in the fossil record as recently as twenty million years ago. They are a close relative of sharks and rays, and must continually swim in order to keep water flowing over their gills. The larger species of Manta, M.Birostris, has been known to grow to a disc width (from tip to tip of each pectoral fin) of 7m, and weighing up to 2 tonnes. It is also thought that they can live to be fifty years of age, with some estimates reaching one hundred, although unfortunately we must study mantas for many more years before we can be certain.

Conservation efforts to protect these precious animals are gradually starting to have positive effects worldwide. Both species of manta are currently being reassessed for the IUCN Red List, which examines each species against a range of criteria to identify issues of concern to species survival; both Alfredi and Birostris are currently listed as ‘Vulnerable’ to extinction. The oceanic manta has also been listed on Appendix I and II under the Convention of Migratory Species (CMS).