任職於世界自然保育聯盟轄下的鯊魚保育特別小組成員，同時身兼斯克雷普斯海洋研究所（Scripps Institution of Oceanography，SIO）博士後研究員的包姆(Julia Baum)對此表示，「在幾乎無法遏止捕獵鯊魚的高度壓力之下，許多鯊魚都面臨了瀕臨絕種的危機。」
Once plentiful sharks are vanishing from the world's oceans, and some species are even at risk of extinction a shark expert told fellow scientists at the annual conference of the American Association for the Advancement of Science, which concluded on Monday.
The global status of large sharks has been assessed by the IUCN-World Conservation Union, which maintains the Red List of Threatened Species.
The assessment finds that many large shark species have declined by more than half due to increased demand for shark fins and meat, recreational shark fisheries, as well as tuna and swordfish fisheries, where millions of sharks are taken as bycatch each year.
"As a result of high and mostly unrestricted fishing pressure, many sharks are now considered to be at risk of extinction," said Julia Baum, a member of the IUCN's Shark Specialist Group and a postdoctoral fellow at Scripps Institution of Oceanography in San Diego.
"Of particular concern is the scalloped hammerhead shark, an iconic coastal species, which will be listed on the 2008 IUCN Red List as globally 'endangered' due to overfishing and high demand for its valuable fins in the shark fin trade," said Baum.
Baum pointed out that fishing for sharks in international waters is unrestricted, and she supports a recently adopted United Nations resolution calling for immediate shark catch limits. Baum also supports a ban on shark finning - the practice of removing only a shark's fins and dumping the still live but helpless shark into the ocean to die.
Research at Dalhousie University over the past five years, conducted by Baum and the late Ransom Myers, demonstrated the magnitude of shark declines in the northwest Atlantic Ocean.
All species the team looked at had declined by over 50 percent since the early 1970s. For many large coastal shark species, the declines were much greater - tiger, scalloped hammerhead, bull and dusky shark populations have all plummeted by more than 95 percent.
The first complete IUCN Red List assessment of the status of all Mediterranean sharks and rays has revealed that 42 percent of the species are threatened with extinction. Overfishing, including bycatch, was identified as the main cause of decline by the study, which was released in November 2007.
"From devil rays to angel sharks, Mediterranean populations of these vulnerable species are in serious trouble," said Claudine Gibson, Programme Officer for the IUCN Shark Specialist Group and co-author of the report.
"Our analyses reveal the Mediterranean Sea as one of the world's most dangerous places on Earth for sharks and rays," Gibson said. "Bottom dwelling species appear to be at greatest risk in this region, due mainly to intense fishing of the seabed."
New research unveiled at the AAAS conference suggests that sharks migrate along fixed routes between well-established gathering places.
Peter Klimley, director of the Biotelemetry Laboratory at the University of California-Davis, has used electronic tags to track scalloped hammerhead sharks along their migration routes in the tropical Eastern Pacific Ocean. Their results suggest that these sharks speed between a series of "stepping stone" sites, near coastal island groups ranging from Mexico to Ecuador.