The IUCN Red List of Threatened Species – a critical indicator of the health of the world’s biodiversity – has assessed 93,500 animal species since it began its work in 1964. Its research found that over 26,000 species are threatened with extinction – that is, 27 per cent of all assessed species. Sharks and ray, or Chondrichthyes – characterized by their cartilaginous skeletons – are under intense pressure. There are 1,041 known Chondrichthyes species and, of these, 181 (17.4 per cent) are classified as threatened: 25 (2.4 per cent) are assessed as Critically Endangered (CR), 43 (4.1 per cent) Endangered (EN), and 113 (10.9 per cent) Vulnerable (VU). Within this group are the manta rays (Manta birostris and Manta Alfredi), charismatic, filter-feeders found in tropical and sub-tropical waters around the world.