Unravelling shark populations

Using DNA to discover shark populations and monitor the sources of fins in international trade 

The demand for fins and other shark products continues to drive the overfishing of shark species and populations worldwide. Even though the DNA forensic tools pioneered by the SOSF-SRC and Guy Harvey Research Institute can rapidly determine the species of shark from market-derived products, the geographic population divisions of most globally distributed sharks are poorly known, making it nearly impossible to determine even the general geographic area that traded shark products originated from. This means that some shark species and populations are perhaps being subjected to disproportionate and unsustainable levels of fishing without our knowledge. If this is the case, some shark populations may be eradicated before we realise it is happening.

The SOSF-SRC is addressing this issue for several fished shark species, in collaboration with researchers from around the world. Ongoing research shows that many shark species, despite their ability to travel thousands of kilometres, are typically made up of smaller genetic divisions (stocks) than assumed. Each of these stocks must receive targeted management, and in some cases even urgent protection by national and regional laws, to prevent their further depletion and the attendant loss of important genetic diversity. The discovery of discrete shark genetic stocks also provides an opportunity to track the geographic origin of shark products already in international markets that are distant from fishing sites. The information being provided is essential for developing scientifically based national legislation and international treaties to help the recovery of sharks on a global scale.