Ocean News

Day 3 at Sharks International

15th June 2010

It was the day after World Ocean’s Day and not a scientist was stirring in the arctic temperatures of the Sharks International’s conference rooms. Instead we were celebrating underwater in the warm Coral Sea and exploring the tremendous diversity of coral life, which forms the Great Barrier Reef.

The next day we were immersed once again in a series of talks about the status of sharks on our blue planet and the many ways that researchers are uncovering their secrets. The morning began on a very different note – with a talk on shark control programs (including the shark nets off South Africa’s Kwa-Zulu Natal) by Geremy Cliff from the South African Shark Board. After listening to a series of rather depressing talks all morning on the animals caught in shark safety nets (fishing gill nets), targeted large-shark fisheries and illegal shark fisheries we were treated to an afternoon focused on genetic and molecular techniques in shark research.

One of the biggest difficulties in fisheries management is the widespread distribution of most species and the fact that sharks don’t acknowledge international boundaries. Dr. Shivji, based at the Save Our Sea Shark Research Centre and Guy Harvey Research Institute in Florida, USA, gave us a “first-look” analysis of population genetic structure in sharks. He revealed that nearly all species of sharks with global distributions have different inter-ocean basins populations and distinct genetic population structure has also been detected within ocean basins. In fact, the scale of some populations may be on an even smaller geographic scale, meaning the sharks in your local waters may belong to their own genetic population. These discoveries are an important conservation flag. The major significance of these findings is being able to assess and manage sharks on a population-specific basis. The number of species in one area might be healthy, but elsewhere that same species may be in danger of extinction, and because they are genetically distinct populations the healthy populations won’t fill the gap of a population that is fished off our planet. “Over the last five years we have discovered through genetic research that the population structures of sharks are different to what we used to assume. This information needs to be used by management bodies to help conserve shark populations,” says Dr. Shivji.