DNA Helps Scientists Trace Shark Fins

Groundbreaking new DNA research has, for the first time, traced scalloped hammerhead sharkfins from the burgeoning Hong Kong market all the way back to the sharks’ geographic origin.  In some cases the fins were found to come from endangered populations thousands of miles away, which points the way to a better protection of these sharks from the international trade.

The U.S. has proposed that the Convention on International Trade in Endangered Species (CITES) list the scalloped hammerhead and five other shark species under the organization’s Appendix II, which would require permits for, and monitoring of, all trade in these species across international boundaries.  Knowing the species and geographic origin of fins being traded would allow management and enforcement efforts to be allocated more effectively.

Using CSI-like methods known as “genetic stock identification” or GSI, Dr. Demian Chapman with the Institute for Ocean Conservation Science at Stony Brook University (SBU) and Dr. Mahmood Shivji, senior author on the paper and Director of the Guy Harvey Research Institute (GHRI) and Save Our Seas Shark Center, both at Nova Southeastern University (NSU) in Florida along with Danillo Pinhal of the GHRI and Universidade Estadual Paulista, Brazil, analyzed fingernail-sized DNA samples from 62 scalloped hammerhead shark fins that had been obtained in the Hong Kong fin market.  By examining each fin’s mitochondrial DNA sequence – a section of the genetic code passed down by the mother and traceable to a sharks’ regional birthplace – the researchers were able to exactly match 57 of the 62 fins to an Atlantic or Indo-Pacific ocean origin.  The team also analyzed mitochondrial sequences taken from 177 live scalloped hammerheads in the Western Atlantic and determined that the species is further divided into three distinct stocks in this region: northern (U.S. Atlantic and Gulf of Mexico), central (Belize and Panama), and southern (Brazil).  The scientists traced 21 percent of the Hong Kong fins back to these Western Atlantic stocks.

Dr. Mahmood Shivji said:

“Although we’ve known that a few million hammerhead shark fins are sold in global markets, we now have the DNA forensic tools to identify which specific hammerhead species the fins originate from, and in the case of scalloped hammerheads, also what parts of the world these fins are coming from.”

Scalloped hammerheads in the region have been categorized as endangered by the IUCN (International Union for the Conservation of Nature) since 2006.  This coastal species appears to have collapsed in the western North Atlantic and Gulf of Mexico.

The research published early this month in the journal Endangered Species Research was led by the Guy Harvey Research Institute and the Save Our Seas Shark Center at Nova Southeastern University and the Institute for Ocean Conservation Science at Stony Brook University and funded by the Institute for Ocean Conservation Science at SBU, the Guy Harvey Research Institute at NSU and the Save Our Seas Foundation.

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