July 29, 2013 Biologists have analysed tissue samples of 115 spotted whiprays of the Himantura genus, collected in various parts of the Indio-Pacific region. By means of genetic markers -- as opposed to morphological criteria only -- the scientists were able to describe these leopard-skin whiprays in detail and demonstrate that they are isolated from each other in terms of reproduction. They have also discovered a new species that they call Himantura tutul, which belongs to a genetic line that is totally distinct from the three other species that are known in the same group: H. leoparda, H. uarnak and H. undulata. They frequent the same costal habitats but occupy different ecological niches.
Distinguish in order to protect
These studies should help to assess the state of these whipray populations and improve their conservation. Knowing the biological characteristics of each species will for instance help to redefine a minimum size for fishing purposes to avoid the catching of juveniles that belong to the larger species. Determining their geographical distribution and habitats will also make it possible to protect the breeding and nursery habitats of each species.
Economical and ecological interest
Ocellated whiprays can grow over 1.50 metres wide. These large animals start breeding fairly late, at the age of 5 or 10 years, and only in small numbers. Their populations are therefore very vulnerable. Fished for food and especially for their skin that is sold to tanneries in South-East Asia, they are threatened almost throughout the tropical Indo-West Pacific. Their overfishing will in time jeopardise a whole segment of the economy in Indonesia, which is the largest shark and whipray exploiter with 30% of all catches worldwide. In less than twenty years, the amount fished in the Java Sea has been divided by ten! As high-level predators, whiprays also play an important role in regulating ecosystems. Their extinction will threaten the functioning of coastal marine environments.
The International Union for Conservation of Nature (IUCN) estimates that 36% of the 650 ray species known in the world are at risk of becoming extinct, including leopard whiprays that are classified as "vulnerable." A better identification of these singular animals is the first vital step towards their conservation.
Did you know?
Ocellated whiprays have one or two venom glands at the base of their tail to protect them against their natural predators, namely sharks and killer whales. Their sting is painful and potentially infectious, with serious consequences if not treated correctly.
Other social bookmarking and sharing tools:
- Philippe Borsa, Jean-Dominique Durand, Kang-Ning Shen, Irma S. Arlyza, Dedy D. Solihin, Patrick Berrebi. Himantura tutul sp. nov. (Myliobatoidei: Dasyatidae), a new ocellated whipray from the tropical Indo-West Pacific, described from its cytochrome-oxidase I gene sequence. Comptes Rendus Biologies, 2013; 336 (2): 82 DOI: 10.1016/j.crvi.2013.01.004
Note: If no author is given, the source is cited instead.