[ASC-media] Subject: ASC-media Media Alert
w.ellery at aims.gov.au
Fri Mar 26 09:25:49 EST 2004
26 March 2004
New study indicates shark numbers under threat
A new study conducted by the Australian Institute of Marine Science,
using a unique underwater survey technique, has revealed that fishing
pressure could be taking its toll on parts of northern Australia's
dwindling shark population.
Fisheries authorities have been concerned for some time the
spiralling number of foreign boats targeting sharks in sections off
Australia's north coast has seriously depleted stocks. Fishermen are
lured by the prized shark fin, a delicacy in Asian cuisine, and in
high demand fetching more than $100 per kilo.
The Australian Government Department of Agriculture, Fisheries and
Forestry enlisted AIMS to test its non-destructive techniques to
survey shark abundance and provide a census of sharks in and around
the MOU 1974 box, a region Australia has allowed traditional
Indonesian fishermen in unmotorised boats to work.
The area under survey was Mermaid Reef in the Rowley Shoals, a
Commonwealth Marine Protected Area closed to all fishing, and Scott
Reef in the MOU 1974 box. Scientists were able to gauge the impact of
fishing by comparing the numbers found inside the MOU box with
Using a fleet of Baited Remote Underwater Video Stations (BRUVS),
designed by AIMS researcher Mike Cappo, the scientists were able to
attract, count, and measure the sharks.
Compared with data from an expedition to the same region in 1999 the
survey revealed a rapid decline in shark numbers at Scott Reef Mr
"The number of sharks observed inside the box is far less than those
outside," he said.
Analysis of the BRUVS tapes showed that it took twice as long for
sharks to appear at Scott's reef than at Mermaid reef further
suggesting that they were much less abundant.
Project Leader, AIMS researcher Dr Mark Meekan said the sharks more
valuable for the trade in fins were not sighted at Scott Reef but
were abundant at Mermaid Reef.
"A range of evidence suggests that over-harvesting is the most
plausible explanation for these differences in abundance of sharks
between Mermaid and Scott Reef," he said.
"The shark stocks in the MOU box are extremely low and it is
essential we take a closer look at the situation. There are
certainly indications that foreign fishing pressure may be impacting
shark numbers," Dr Meekan said.
Mike Cappo said remedial measures must include an alternative source
of income for the poor artisanal fishermen who rely on the fishery.
The team also tested an acoustic survey method based on centuries old
technology where rattles were once used to attract sharks in a bid to
"We used sound to attract the sharks into the field of the cameras
and counted them using the video system. We were also able to measure
the size of the sharks and assess bio-mass as well," said Dr Meekan.
The scientists said there needs to be a wider application of the
surveys in the north in the immediate future to provide the
authorities with the evidence needed to remedy the disturbing
findings of the report.
Footage of BRUV vision and Indonesian fishing boats working the MOU
box (courtesy of Customs) is available on request.
The report is available at:
Dr Mark Meekan, AIMS biologist, Mob,0429 101 812, Email: m.meekan at aims.gov.au
Mike Cappo, AIMS Experimental Scientist, Ph 07 4753 4262, Email:
m.cappo at aims.gov.au
Wendy Ellery, AIMS Media Liaison, Ph 07 4753 4409, Email: w.ellery at aims.gov.au
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