New study using DNA Identification techniques provides valuable information on Madagascar's shark fisheries
March 3, 2011
A study that used genetic techniques to study remote shark fisheries in northeastern Madagascar has demonstrated the presence of at least 19 species there, and the most commonly encountered species include those that are consider400ed to be endangered, threatened, or vulnerable. As a result of these findings, the study’s authors conclude that conservation efforts should focus on further study of the fishery, temporal and spatial fishery restrictions to protect endangered species, and potential restrictions of the use of large mesh gillnets.
In this poverty-stricken country, the lucrative market for shark fins has contributed to a decline in the fisheries catch. Due to the remoteness of the shark fisheries of Madagascar, there have been very few studies of them and monitoring them proves to be challenging. Using DNA barcoding and species-specific PCR (polymerase chain reaction) assays, the researchers were able to provide baseline information regarding the shark species harvested in the area to contribute to better management of these fisheries.
By analyzing the DNA of the fin samples of 280 individual sharks that were taken from and near Antongil Bay, Madagascar, in 2001 and 2002, the researchers were able to identify at least 19 species, of which the most common were scalloped hammerhead (32%), milk (16.7%), spinner (12%) spottail, (11.7 %), and largenose (5.4%). The scalloped hammerhead is considered to be “Endangered,” the spottail and spinner are considered “Near Threatened,” and at least four additional species occurring in the fishery are considered “Vulnerable” on the International Union for the Conservation of Nature (IUCN) Red List. Antongil Bay appears to be a breeding area for scalloped hammerhead, milk, and possibly spinner and bull sharks. Because both juveniles and pregnant females are taken in this fishery, this could have further negative impact on these species.
Co-authors of the paper are Phaedra Doukakis, Robert Hanner, Mahmood Shivji, Cecilia Bartholomew, Demian Chapman, Eugene Wong, and George Amato. Contributors include Malcolm Smale, Mananjo Jonahson, Ellen Pikitch, Howard Rosenbaum, Anna Rothschild, and Matthew S. Leslie.
This researched was funded by the Wildlife Conservation Society and the Canadian Barcode of Life Network (via the Natural Sciences and Engineering Research Council of Canada and other sponsors listed at www.BOLNET.ca).
For more information about this paper, “Applying genetic techniques to study remote shark fisheries in northeastern Madagascar” please go to: http://informahealthcare.com/doi/abs/10.3109/19401736.2010.526112.