Living Manta Ray Hybrid found in the Red Sea
The Cousteau Society
22. October 2013
LIVING MANTA RAY HYBRID FOUND IN THE SUDANESE RED SEA –
FIRST RECORD IN THE WORLD!
The first hybrid Manta ray has been identified off the Red Sea coast of Sudan following a pioneering research trip in late 2012 carried out by scientists from The Cousteau Society, The Deep and The University of Windsor in collaboration with Sudan’s Wildlife Conservation General Administration, The Red Sea University and The Red Sea State Government.
The first field mission called the Red Sea Shark and Ray Management and Conservation program was a huge success with the first living Manta alfredi/Manta birostris hybrid being discovered following molecular genetic analyses by Marine Biologists based at the Great Lakes Institute for Environmental Research (GLIER) at the University of Windsor, and published in the journal Marine Biodiversity.
During October and November 2012, the expert team of international researchers and Sudanese partners, conducted state-of-the-art fieldwork in the Dungonab Bay Marine Park and on the offshore coral reefs of Sudan, to study the iconic and vulnerable species of Manta ray and to prepare the road for future missions focused on Sudan’s spectacular shark populations.
The team successfully tagged and released 22 manta rays, through internal implantation of acoustic tags and dorsal fin attachment of satellite tags. In addition, Mantas were also sampled for genetic studies and the analysis of one individual revealed a surprising result: the first record of a living hybrid of two distinct Manta species the Reef Manta Ray (Manta alfredi) and the Giant Manta (Manta birostris).
Until recently scientists only recognised one global Manta species. The genus was re-evaluated and two species, Reef Manta Ray (Manta alfredi) and Giant Manta Ray (Manta birostris) were identified.
In a few locations, the Giant Manta Ray and the Reef Manta Ray occur together, but these species typically exhibit different habitat use and movement patterns and were thought to be reproductively isolated.
Hybridisation among species carries serious implications for estimating population connectivity and identifying critical habitat for Mantas. This is only the second documented case of hybridisation in Elasmobranchs (sharks and rays), but using molecular genetic technologies we may find that hybridisation is more widespread than previously thought.
‘Hybrid individuals are evidence of connectivity beyond a geographic or population context, ultimately blurring the definition of what we call a species.’ said Ryan Walter lead author on the paper.
Little is known about the movements and populations sizes of manta rays in the region. These animals are a symbol of freedom in the oceans and typically live for over 20 years and are slow to reach sexual maturity.
Their inherent inquisitive nature with humans and boats makes them particularly susceptible to fisherman and they are easily targeted due to their large size, slow speed and tendency to aggregate in shallow water coastal areas.
The overall research programme aims to address critical issues to conserve Sudan’s unique Manta Ray population and establish a long term action plan which can be followed by future generations. Both species are labeled as vulnerable on the IUCN Red List and have recently been listed on the CITES appendix II list following concern over increasing global exploitation rates.
The occurrence of hybridization further stresses the importance for monitoring, conservation and management of threatened species, which are the principal objectives of this programme.
Colin Brown, Chief Executive at The Deep said: “This is pioneering research at its best, and this essential information will help to create a comprehensive management and conservation strategy to protect this globally iconic species. This project will have long term benefits for the entire ecosystem on which Manta rays depend.”
Tarik Chekchak, Director Science and Environment at Cousteau Society added: “This new finding demonstrates how developing Marine Protected Area networks is crucial, in particular in pristine areas not yet impacted by unsustainable development. Our current study on sharks and rays in the Red Sea is an encouragement to protect the whole habitat of the species.”
Nigel Hussey, lead scientist on the project from the University of Windsor and Ocean Tracking Network said, ‘The marine protected area of Dungonab Bay, Sudan, represents one of few unique sites on our planet where an extraordinarily large number of these animals can be found. The occurrence of hybridization within this population, and the potential for hybrids to act as dispersal agents of genetic diversity, is a promising sign for these threatened species, but also raises questions over individual species management.’
Source: Cousteau Society
Related Scientific Paper :
R P Walter et al. 2013 :
Marine Biodiversity. DOI 10.1007/s12526-013-0183-2