According to scientific findings released today in the peer-reviewed journal Marine Policy, the number of sharks killed each year in commercial fisheries is estimated at 100 million, with a range between 63 million and 273 million. The authors also warn that the rate of fishing for shark species, many of which grow slowly and reproduce late in life, exceeds their ability to recover.
The estimates in the study – calculated by adding landed catch data reported to the United Nations Food and Agriculture Organization to estimates of unreported landings, finned sharks, and other discards of dead sharks – comes at a critical time. Governments convene this week in Bangkok to consider shark protections under a treaty concerned with regulating international wildlife trade – the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). The Pew Charitable Trusts is calling for immediate action to increase safeguards for some of the most vulnerable species.
"Biologically, sharks simply can't keep up with the current rate of exploitation and demand," said Boris Worm, a marine biologist at Dalhousie University in Halifax, Nova Scotia, and lead author of the study. "Protective measures must be scaled up significantly in order to avoid further depletion and the possible extinction of many shark species in our lifetime."
"This groundbreaking study confirms that people are killing an enormous number of sharks," said Elizabeth Wilson, manager of global shark conservation at Pew. "We are now the predators. Humans have mounted an unrelenting assault on sharks, and their numbers are crashing throughout the world's oceans."
The catch of sharks in commercial fisheries for their fins, meat, liver oil, cartilage, and other parts remains largely unregulated in most of the world, driving some populations toward extinction. This week, 177 governments from around the world are expected to attend the March 3-14 meeting of CITES in Bangkok. Proposals to regulate the international trade of five species of sharks and two related manta rays have been submitted and co-sponsored by 37 countries for consideration at the meeting. The proposed shark species – the oceanic whitetip, porbeagle, and three types of hammerheads—are among the most valuable and vulnerable sharks in international trade.
A simple vote ‘yes' to support their listing could turn things around for some of the world's most threatened shark species. Elizabeth Wilson, Manager, Pew Global Shark Conservation
"Countries should seize this opportunity to protect these top predators from extinction," Wilson said.
CITES, which was agreed to in Washington, DC, in 1973, offers protection to more than 30,000 animal and plant species around the globe. It has been instrumental in preventing their extinction and is generally recognized as one of the most effective and best-enforced international conservation agreements.
- Estimates of global shark mortality by commercial fishing were calculated by adding landed catch reported to the UN Food and Agriculture Organization (FAO) with estimates of unreported landings, finned sharks, and other dead discards.
- The study also calculated the exploitation rate for sharks as a group and determined that it exceeds the average rebound rate for many shark populations, which means that sharks are currently being removed from our oceans at an unsustainable rate.
- CITES Appendix II listings can serve a critical function in conserving global shark populations by helping to ensure that their international trade is sustainable and legal.
- CITES provides unique benefits that supplement and bolster the limited conservation and management measures adopted by some regional fisheries management organizations, as well as regulations established by individual countries.
- CITES has historically focused more on land-based species, but in recent years the number of marine species proposed for protection has increased. Marine fish species currently protected include the whale shark, basking shark, great white shark, and sawfish.
- The Pew Charitable Trusts provided travel support to two meetings where a subset of the authors discussed the paper, among other topics.