Shark Depredation and Unwanted Bycatch in Pelagic Longline

Shark Depredation and Unwanted Bycatch in Pelagic Longline Fisheries
were provided on the life status of sharks caught subsequent to the
1991 requirement that for finning to be practiced, the whole carcass
had to be retained. If, as is reported, the 1991 requirement ‘effectively
prevented them (the vessels) from retaining shark fins whilst in
Australian waters’, then the high survival prospects (Moyes et al
2006) of post release sharks would obviously have contributed to
there having been no apparent trend in abundance as a consequence
of fishery impact (based on observed catch rate data in the five
years subsequent to 1991). And in New Zealand where similar
amounts of the same species were being caught and actually
processed for their fins throughout the 10-year period, impact
of this is thought to not have had a serious effect on shark stocks
(Francis et al 2001). Over a period of approximately 10 years (1990s)
Australia’s domestic longline fishery had the unrestricted option
of utilizing all sharks, even just for their fins. Whether this has
had any bearing upon present day shark catch rates is not known.
Five species, great white, grey nurse, megamouth, green sawfish and
Herbert’s nurse shark are prohibited take and of these there have
been 5 grey nurse and one great white interaction recorded in pelagic
longline fisheries in Australia.
A1.6. Influence of International Initiatives
on Domestic Shark Management
Various international fisheries management initiatives have been
influential or instrumental in subsequent national initiatives
in Australia for improved fisheries management, including the
management of shark bycatch. For example, the United Nations Food
and Agriculture Organization produced the ‘Code of Conduct for
Responsible Fishing’. In 1999, Australia ratified the United Nations
Agreement for the Conservation and Management of Straddling
Fish Stocks and Highly Migratory Fish Stocks, and became a party to
the United Nations Convention on the Law of the Sea. Australia is
a signatory to the Convention on International Trade in Endangered
Species (CITES), which can mean an obligation in relation to particular
shark species. Australia has produced a Shark Assessment Report
(SAR), a requirement of member nations in response to the Food and
Agriculture Organization of the United Nation’s International Plan of
Action on sharks. The SAR identifies conservation and management
issues associated with shark catch, the most significant of which
are those including target, by product and bycatch. There were 24
priority requirements identified. They included better recording
of all shark catches, protection of species with poor conservation
status, cross jurisdictional management of stocks, national controls
on shark finning, the need to develop shark bycatch reduction
methods, handling practices of returned catch, ecosystem effects of
shark management practices (specifically trophic cascade), impact of
increased shark populations, impact of prey removal and the impact
of market demand on shark populations. Australia’s management of
the practice of shark finning is also consistent with its obligation to the
United Nations Food and Agriculture Organizations Code of Conduct
for Responsible Fisheries to fully utilize bycatch and by product species.
This practice is reiterated to signatory nations to the FAO IPOA
sharks, in that incidental shark capture should not result in waste, and
capture of non-utilized species should be minimized. Australia is also
a member of Regional Fisheries Management Organizations such as
the Indian Ocean Tuna Commission (IOTC) and the Commission for
the Conservation of Southern Bluefin Tuna (CCSBT) under which
shark bycatch management specifically can be further addressed. For
instance, within such processes, Australia entered into a Bilateral Shark
Bycatch Code of Practice agreement with Japan, the objective being to
ensure all sharks taken are either: released alive and undamaged (i.e.
not mutilated or cut prior to release), or retained whole, not just fins
and killed first before being processed.
A1.7. National Management Processes
for Sharks in Australia
Commonwealth fisheries bycatch is managed by several procedures
such as by a direction and/or a specific inclusion within a statutory
Management Plan, as a condition or a bycatch regulation prescription
of a fishing permit, through an urgent temporary order or as a
prohibition against the take of a particular species in the Fisheries Act.
Increasing catches of sharks and the inherently low productivity
of sharks are the reasons for concern, not just in Australia but also
worldwide for populations of some shark species. But, the relatively
low market value of sharks is considered to have been the reason
why few countries have managed shark catch in the past (SAG and
Lack, 2004). Without appropriate management in place to prevent
or at least contain increased exploitation potential, today’s bycatch
(discarded sharks) can become a by-product tomorrow as determined
by a changing market demand. From a scientific perspective,
management of pelagic sharks is complicated by the unknown
effects on the oceanic ecosystems of removing large number of these
top predators. Also, because sharks have historically been of low
economic value in most countries, data quality has been poor.
The above situation precipitated development of the International
Plan of Action for the Conservation and Management of Sharks (FAO
1999), to which Australia responded by establishing a Shark Advisory
Group in 2000 for the purpose of developing a shark assessment
report which was released in 2001 (Rose and SAG 2001). This
report highlighted the necessity for development of an Australian
Shark-plan (SAG and Lack 2004) ‘to ensure the conservation and
management of shark resources and their ecologically sustainable
use’. Specifically related to fisheries impacts, the main objectives
of the plan were to ensure sustainability of target and non-target
catches, to minimize incidental catches of sharks that are not being
utilized and for those that are utilized, minimize waste such as when
fins only from the shark are retained, in accordance with article 7.2.2
of the Code of Conduct for Responsible Fishing (FAO 1995). The
NPOA–sharks provides a guide to incorporating shark conservation
and management issues into the various fisheries management plans.
It recommends examining the methods used to manage and reduce
shark by-catch.
The pelagic longline fishery was identified as a potential source of
significant shark catches and attempts have been made to evaluate
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