GMSA News: Shark News (22nd Febuary 2007)

Photo by SR Livingtsone, Great White Shark in South Africa

Pelagic Shark workshop, Febuary 2007, Oxford, UK

Scientists with the World Conservation Union, which publishes the Red List of Threatened Species, have upgraded the "threat" category of a number of shark species. Those now considered "vulnerable to extinction" include the shortfin mako, a favourite of recreational fishermen, and the long-tailed thresher shark. Scientists say over-fishing is a principal reason for the decline.

The World Conservation Union's (IUCN) shark specialist group announced its re-assessments at a workshop in Oxford, UK. Several species are now threatened with extinction on a global scale. "The workshop results underscore the urgent need for international fishery commissions to limit fishing for these vulnerable species and strengthen regulations on the wasteful practice of finning."  said Sarah Fowler.

 "Despite mounting threats and evidence of decline, there are no international catch limits for pelagic (ocean-going) sharks," said Sonja Fordham, deputy chair of the shark specialist group and policy director for the Shark Alliance. Cutting off shark fins, which are prized for soup in some east Asian cultures, is banned in many fisheries. But IUCN says enforcement is often weak.

Maturity problem

Sharks are more vulnerable than many other types of fish to environmental threats because they generally mature slowly and reproduce relatively late in life.

"The qualities of pelagic sharks - fast, powerful, wide-ranging - too often lead to a misperception that they are resilient to fishing pressure," commented Sarah Fowler, shark specialist group co-chair. "But several species are now threatened with extinction on a global scale."

The world's biggest fish, the whale shark, is one of them. Researchers found evidence last year that so many large specimens are being caught that the average length of the fish is falling. However, many of the most threatened species are found in rivers and coastal waters, with the Ganges shark, the striped dogfish of South America and the European angel shark among those considered "critically endangered".

Photo by RT Graham, Whale shark

The new assessment sees the status of the scalloped hammerhead, another coastal species, worsen from "near threatened" to "endangered". Hammerheads are among the most commonly caught sharks for finning. Accidental catching by fishermen is as much a threat as targeted fishing.

The Oxford workshop is one of a series in which IUCN scientists are aiming to generate a more accurate picture of the threats to sharks and their close cousins, the rays. Many of these species have not been studied sufficiently for scientists to assess their status, yet threats in the form of fishing and habitat disruption are clearly present.

BBC News Article http://news.bbc.co.uk/2/hi/science/nature/6385995.stm