Shark Depredation and Unwanted Bycatch in Pelagic Longline

Appendix 1
Australia Longline Tuna and Billfish Fishery:
Industry Practices and Attitudes towards Shark Depredation
and Unwanted Bycatch
Nigel Brothers, Consultant, Marine Ecology and Technology,
brothersbone@yahoo.com.au
A1.1. Fisheries Management Jurisdiction
Of Australia’s eight states and territories, only one (Australian Capital
Territory) has no responsibility for shark management. The others,
Northern Territory, Queensland, Western Australia, New South
Wales, South Australia, Victoria and Tasmania all have jurisdiction
extending 3 nautical miles seaward. Beyond this, management is
either a sole Commonwealth responsibility or one shared jointly
with a state or territory. This extends to the edge of the 200-mile
Exclusive Economic Zone (EEZ) although commonwealth fisheries
management requirements can apply to Australian flagged vessels
that may fish beyond this zone.
A1.2. Shark Fisheries in Australian Waters
Of the 10,000 t annual world shark catch, Australia is responsible for
1.26%, ranking it 19th of the 23 major shark-fishing countries (Rose
and McLaughlin 2001). Excluding fisheries in which sharks are considered
bycatch and or by product, Kailola et al (1993) list seven
species of sharks, whiskery Furgaleus macki, school Galeorbinus
galeus, gummy Mustelus antarcticus, dusky whaler Carcharhinus
obscurus, bronze whaler Cartharhinus brachyurus, black tip,
Cartharhinus tilstoni, spot-tail Carcharhinus sorrah, that are
subjected to targeted fishing by use of gillnet, longline (demersal, as
distinct from pelagic) handline or dropline. In addition to these at
least 25 species are commercially exploited with saw Pristiophorus
curratus and P.nudipinnis, elephant Callorhynchus millii, sandbar
C.plumbeus and wobbegong (orectolobidae) sharks included amongst
these. They can be taken in the shark target fisheries using any of
the above fishing methods, or incidentally in trawl or seine fisheries.
In addition to the seven shark species considered to be the target of
seven recognized commercial shark fisheries, other species are taken
by targeted recreational and game fishers and in two shark control
programs aimed at improving human safety. At least 70 other
commercial fisheries catch sharks incidentally. Between 1974 and
1986 Australia’s northern waters were gillnetted by Taiwanese vessels,
primarily targeting spot-tail shark (carcharhinus sorrah) and several
fish species (Stevens 1999). Australian vessels started exploiting these
stocks in about 1980 using both gillnet and longlines.
Of Australia’s quantified shark catch, two-thirds by weight (66%)
is comprised of only 15 species with the gummy shark at 27.7%
constituting the greatest proportion of the total catch (Rose and SAG
2001). Whilst the next highest proportion at only 8.9% is of school
sharks, 30% of sharks caught are not actually identified, and those
caught in pelagic longline fishing are not represented at all in the
above percentages because in this fishery the only documentation, if
any, is by numbers, not weight.
Meat is the most important product from sharks with its value
rang-ing from around AU$7.30/kg for school and gummy sharks to
as little as AU$1.00/kg for species such as hammerhead with $3/kg
being usual for a number of commonly marketed species. Around
8,000 ton of sharks are sold annually from Australia’s fisheries with
no more than around 17 tons being exported to 6 countries (Japan,
Greece, Korea, Hong Kong, Malaysia and Singapore) and up to 233
tons being imported annually from five countries, (South Africa,
New Zealand, Spain, New Caledonia, and Philippines).
Of the estimated 94 tons shark fin market worth approximately
AU$5.5 million it was estimated that 35% was derived from the
practice of finning in the pelagic longline fishery where only the fins
were being retained (prior to 1999). Rose and McLaughlin (2001)
suggest that these fins were derived from 3,900 t of sharks, equivalent
to one third of all other shark production (1998/99).
In addition to meat and fins, other shark products include cartilage
derived from backbones and skulls as well as from fins, amounting
to 27 tons worth up to AU$5 per kg (Rose and Mc Laughlin 2001).
Shark liver oil, and shark skins are also utilized but the extent of
this is poorly understood but considered minimal with most shark
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