"The shark fin trade is notoriously secretive. But we were able tap into fin auction records and convert from fin sizes and weights to whole shark equivalents to get a good handle on the actual numbers," says lead author Shelley Clarke, Ph.D, an American fisheries scientist based in Hong Kong and Japan.
A team of researchers calculated the number of sharks represented in the fin trade using a unique statistical model and data from Hong Kong traders. When the figures were converted to shark weight, the total is three to four times higher than shark catch figures reported to the United Nations Food and Agricultural Organization (FAO).
"Without any real data, numbers as high as 100 million had been floating around for a while, but we had no way of knowing whether or not this was accurate," says Ellen Pikitch, Ph.D., co-author and executive director of the University of Miami's Pew Institute for Ocean Science. "This paper, which produces the first estimate based on real data, shows that the actual number of sharks killed is indeed very high but is more likely to be in the order of tens of millions, with a median estimate of 38 million sharks killed annually."
Concern about the shark finning trade has grown over the past few years as demand has surged beyond sustainable levels for slow-to-produce shark populations and without regulation in most countries. Three shark species are listed on the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), and 20 percent are threatened with extinction according to the 2006 Red List of Threatened Species.
Used in shark fin soup, a delicacy served at Chinese weddings and other celebrations for centuries and more recently at business dinners in Southeast Asia and the Pacific Rim, fins are the most valuable part of the shark, which typically are sliced off as the shark, sometimes still alive, is thrown back into the ocean. The shark fin trade appears to be keeping pace with the growing demand for seafood--up five percent per year in mainland China. Determining whether shark populations can continue to withstand the magnitude of catches estimated by Clarke and her team depends upon the size and status of each population.
"One of the most productive sharks is the blue shark, and it appears that the catch rate is near the maximum sustainable level," says Clarke. "But such assessments were not available for other, less productive shark species. It is quite likely that sustainable catch levels have already been exceeded in some cases."
The United Nations FAO compiles catch records for sharks and other fish, based on information submitted from member countries. Where possible, the FAO attempts to verify the accuracy of the figures, but verification often is not practical. Many sharks may be recorded as unidentified fish and thus not be recognizable as sharks in the FAO records.
"Due to the low value of shark meat in many markets, shark fins may be the only part of the shark retained, and often these fins are not recorded in the catch log or when landed at ports. I knew we had to somehow access the major markets if we were to accurately estimate the number of sharks killed," says Pikitch, who initiated the project.
Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
18.10.2017 | Materials Sciences
18.10.2017 | Physics and Astronomy
18.10.2017 | Physics and Astronomy