Gland, Switzerland, 25 June 2004 (IUCN - The World Conservation Union). The number of species of sharks and rays on the IUCN Red List of Threatened Species is set to grow. This was the finding of a week-long expert workshop at Mote Marine Laboratory, Florida, to examine the conservation status of the species found in North and Central American waters.
Workshop findings confirm the widely-held belief that slow growing sharks and rays are exceptionally vulnerable to over-fishing, but also reveal that species can recover from depletion if strict management is imposed before populations reach critical levels. The results highlight how species can become endangered through incidental catch, without being the target of fisheries. In many cases, species of “Least Concern” in US waters still face serious threats from unregulated fishing off Mexico and Central America.
Nearly 200 species of sharks and rays in the region were evaluated using the IUCN Red List Categories and Criteria. Categories range from "Extinct" to "Least Concern" and "Data Deficient." Species classified as "Vulnerable," "Endangered" or "Critically Endangered," are considered threatened with extinction and are added to the global Red List. The Red List Categories and Criteria were also used to assess certain regional and specific populations, as well as global ones. The Shark Specialist Group of IUCN’s Species Survival Commission, which convened the meeting, will compile the assessments into a report that will include recommendations for conservation action.
Proposed additions to the Red List include the oceanic whitetip shark of the Gulf of Mexico and New England's thorny skate, both classified as "Critically Endangered," as well as two species of hammerhead sharks, now considered "Endangered." The demise of the oceanic whitetip is blamed on incidental catch (or "bycatch") in high seas tuna and swordfish fisheries combined with demand for their fins. Hammerhead populations have declined due to a combination of factors including recreational over-fishing, high commercial value of their fins and bycatch. Thorny skate was taken from US waters for a European market until last year, but is still caught incidentally in regional fisheries for cod, haddock and flounder.
Participants heightened the alarm over the US Atlantic sand tiger shark, which is proposed to move from a "Vulnerable" listing to the more serious "Endangered" classification. This species produces only two young every two years and is not recovering despite being protected since 1999. The group proposed to retain the 2000 "Vulnerable" classification for the protected Atlantic dusky shark, but stressed an urgent need for a more in-depth population assessment for this exceptionally slow-growing species.
The workshop did reveal some good news for sharks. Thanks to a decade of catch controls, the US population of commercially-important blacktip sharks has been rebuilding and its IUCN threat status was proposed this week as "Least Concern”. The species is still considered threatened off Central America due to the lack of fishing regulations and persistent fishing pressure outside the US. The threat status of barndoor skate off New England was proposed for downlisting from "Endangered" to "Near Threatened" based on a steady population increase over many years, while the Canadian population remains "Endangered."
More than 50 experts took part in the meeting, including scientists from government agencies, universities, private institutions and researchers from Central America. The workshop was the fifth in a global series to assess all the world's shark and ray species and develop regional conservation priorities. Resulting Red List proposals are preliminary until accepted by the global Shark Specialist Group network.