誤捕後存活率高 鋸鰩復育不難 但仍須努力
A global strategy to prevent extinction and promote recovery of sawfishes, devastated worldwide by overfishing and habitat loss, was introduced today by the Shark Specialist Group of the International Union for Conservation of Nature, IUCN.
Sawfishes – warm water, shark-like rays characterized by long, toothed snouts, or rostra – are the largest of the rays, reaching over seven meters in length.
Once found in the coastal waters and rivers of more than 90 tropical and subtropical countries, all five species are today classified as Endangered or Critically Endangered on the IUCN Red List.
The strategy is being launched at the Sharks International conference in Durban and coincides with announcements that two West Africa countries – Guinea and Guinea Bissau – are proposing the listing of sawfishes under the Convention on Migratory Species in November, an action that could boost protections.
Mortality from targeted and incidental fishing is the main threat to sawfish. Their rostra, which they use to detect and wound prey, are easily entangled in many types of fishing gear, particularly trawls and gillnets.
The destruction of key habitats, such as mangroves, also poses a threat to sawfish survival.
“Although these species are perilously close to extinction in many regions, there are some fairly simple ways to help populations recover. For example, we know that sawfish can actually survive capture quite well if handled properly, and hence, basic education of commercial, subsistence, and recreational fishers is central to our conservation strategy,” said Dr. Colin Simpfendorfer, IUCN SSG Co-Chair, Professor of Environmental Science at James Cook University in Queensland.
Dr. Simpfendorfer led the development of the U.S. recovery plan that has improved the status of smalltooth sawfish in Florida.
To complement an existing ban on commercial international sawfish trade, the new strategy calls for national and regional actions to prohibit intentional killing of sawfish, minimize mortality of accidental catches, protect sawfish habitats, and ensure effective enforcement of such safeguards.
Sawfish rostra are universally valued as curios and have been used in traditional medicine in many countries including Mexico, Brazil, Kenya, Iran, India, and China. The rostral teeth are prized as cockfighting spurs in Latin America and the Caribbean. Sawfish meat is consumed in some places; sawfish fins are exceptionally valuable for shark fin soup in Asia. The species also serve as popular aquarium attractions.