Greater Protection Measures for Grey Nurse Sharks
IUCN Shark Specialist Group Endorses Greater Protection Measures for Grey Nurse Shark Off Australia's East Coast
Gland, Switzerland, 27 November 2003 (IUCN) - The Shark Specialist Group of IUCN's Species Survival Commission strongly endorses a proposal by the Queensland Government to better protect the threatened grey nurse shark (Carcharias taurus), off Australia's east coast.
Earlier this year, at a workshop on Queensland's North Stradbroke Island, Shark Specialist Group (SSG) members met to review the status of all sharks that occur in Australian waters. Species were assessed for inclusion in the 2003 IUCN Red List of Threatened Species, released last week.
The workshop findings are outlined in a report "The Conservation Status of Australasian Chondrichthyans" (sharks, rays and chimaeras). Of the 179 shark species assessed, Australia's east coast population of the grey nurse shark was the one causing greatest alarm amongst the experts.
Whilst the species as a whole is listed as Vulnerable on the IUCN Red List, the population of grey nurse shark that occurs off the east coast of Australia is listed as Critically Endangered, facing an extremely high risk of extinction.
Like most shark species, the grey nurse is long-lived, takes several years to reach maturity (hence breeding age) and produces few offspring. Females give birth to only one or two pups every two years. This low reproductive capacity results in the slow recovery of a species, even at the best of times.
The National Recovery Plan for the grey nurse shark, produced by the Australian Government, indicates that recovery conditions are far from ideal for this species. Incidental capture by commercial and recreational line fishers is flagged in the Plan as the most serious continuing threat to the species in south east Queensland and New South Wales (NSW).
The Plan identifies 19 known aggregation sites (where the sharks regularly group) that are considered critical for the survival of the grey nurse shark in eastern Australia. Six of these lie in south east Queensland including five within the Moreton Bay Marine Park and one at Wolf Rock, a proposed extension area for the Great Sandy Straits Marine Park. The Queensland Government is now planning to introduce legislation to safeguard these six sites in the State's south east waters.
As well as protecting the sharks themselves, the SSG believes that shark habitat and prey species must also be conserved.
"Our review of the research and literature on this species confirms our concerns. The grey nurse shark is facing extinction off the east coast of Australia. Extensive and decisive action must be taken now in Queensland to further protect this species and to promote stock recovery," said Associate Professor Michael Bennett of the University of Queensland and SSG member.
There are several facts that underpin the SSG's concerns. Scientific surveys by NSW Fisheries point to a very small population size. Scientists estimate there may be fewer than 500, or possibly even 300 individual grey nurse sharks remaining in the adult population.
Other assessments by NSW Fisheries and Queensland's Parks and Wildlife Service confirm that grey nurse sharks are still being caught and significant numbers are now being seen in both Queensland and New South Wales with fishing hooks in their mouths or bodies.
NSW Fisheries scientists have discovered at least one case where a grey nurse shark died from septicemia, which was caused when the shark swallowed a fishing hook that perforated the intestinal wall. Fisheries Compliance Officers have also apprehended recreational fishers in possession of grey nurse sharks, even though the species is protected under fisheries legislation in NSW, Western Australia, Victoria, Tasmania, and Queensland. Even low levels of mortality can severely hinder the population's recovery given its dwindling numbers.
Recent tagging work by Australia's Commonwealth Scientific and Industrial Research Organisation confirms that grey nurse sharks move out at least as far as 1.3km from the main aggregation area. It is believed that most of this activity occurs at night and is associated with foraging behaviour. While grey nurse sharks generally feed close to the ocean floor, they will also feed and swim in mid-water and close to the surface.
In view of the current situation, the SSG strongly supports proposals by the Queensland Government to protect the six critical habitat sites in south east Queensland from fishing, to a distance of 1.3 km of Wolf Rock and Flat Rock and 1.2km of the other sites.
The Group also supports the introduction of measures to control the activities of divers at critical habitat sites in order to minimise and manage the possible disturbance.
IUCN/SSC Shark Specialist Group website: http://www.flmnh.ufl.edu/fish/organizations/ssg/ssg.htm This includes the report, the Conservation Status of Australasian Chondrichthyans
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