Shark Depredation and Unwanted Bycatch in Pelagic Longline

Shark Depredation and Unwanted Bycatch in Pelagic Longline Fisheries
A7.5.2. Perception of interviewees
Skippers interviewed were of the opinion that they catch 10 to 20
sharks or between 100 and 300 kg of sharks per set. Most felt the blue
shark was the most commonly caught at a rate of up to 15 blue sharks
(or 200 kg) per set. They usually retain most blue sharks (within the
regulations). They report that blue sharks are usually hauled aboard
alive, but die if they become badly entangled in their gear. Most felt
that this capture had no effect on the species, however one skipper
felt that the capture of blue sharks was dramatically threatening the
species. The second most common species caught in their opinion
was the short-fin mako shark. Up to 10 makos are caught per set and
this comprises approximately 20 to 100 kg. They usually retain all
makos (again within the regulations). The economic value of makos
is higher than for blue sharks and thus retained more frequently.
Most makos are alive on capture, but a portion of them are dead.
Most felt that this capture had no effect on the species, however the
same skipper as above felt that the capture of makos was dramatically
threatening the species. Two of the skippers interviewed felt that
shark bycatch was not causing any economic loss to the fishery. Three
felt it was causing economic loss due to loss of bait and time. The
remaining did not know. Only half said that they submitted their
shark catches in their logbook records.
A7.6. Management Framework Relevant to Shark
Interactions
At present there are no accepted mitigation measures for reducing
shark bycatch and this requires investigation. South Africa has a
draft NPOA-sharks, but this has not yet been adopted. However, in
order to address mounting international concern for high levels of
shark bycatch, Marine and Coastal Management, Department of
Environmental Affairs and Tourism, South African Government,
have planned to close the pelagic sector of the shark-directed
longline fishery and place a 10% shark bycatch limit on the tuna and
swordfish fishery. Since 2005 this fishery has been divided into those
targeting swordfish and those targeting tunas. Individuals with a
swordfish permit may only land sharks up to a maximum of 10%
of their swordfish and tuna catch. Individuals with a tuna permit
may only land sharks up to a maximum of 10% of their tuna catch.
Currently shark bycatch accounts for approximately 18% or 25% of
the directed catch (Table A7.4). This is substantially larger than the
suggested 10%, thus many of these shark species will be released or
discarded. Since we have no estimate of post-release survival nor
adequate information on the percentage of species hauled alive, this
may not be sufficient to address mounting concerns.
Shark finning regulations came into effect in South Africa in 1998
under the Marine Living Resource Act of 1998 (MLRA, 1998).
Regulations formed under this act banned finning. The South
African experimental pelagic longline fishery only commenced in
1997 and thus very little information exists on finning practices in
this fishery. Under this regulation sharks were supposed to be landed
whole, which would mean that no finning was allowed. However,
fishers complained that it was impractical to land sharks whole.
Marine & Coastal Management gave concession for fishers to land
the fins with the corresponding trunks, but this was not enforced
as result sharks were definitely finned during this time. A 5% fin to
carcass ratio was introduced last year (2005) in an attempt to stop
finning Further regulations prohibit the use of a wire trace to limit
the retention of shark catches in this fishery.
A7.7. Economic, Social and Ecological Effects,
Including Effects on Fishing Practices, from
Regulations Governing Shark Interactions
The total amount and condition of sharks landed is limited by the
regulations discussed above. Most of the fishers that were interviewed
felt that the 10% regulation was hard to comply with because it doesn’t
reflect the reality. In many cases they catch more than their 10% and
are thus forced to dump or discard dead sharks (Table 4). They felt it
is also problematic because it results in the underreporting of shark
catches. Three interviewees said that this regulation had minimal
economic impact on them, two said that it caused great economic
loss, but was unable to quantify and the remaining didn’t know.
When revenue is acquired from finning this typically goes to the
crew and/or skipper. In some cases these vessels are owner-operator
and thus revenue is accrued to the company. One skipper reported
that they don’t fin at all on his vessel because he doesn’t approve of
the practice. The crew occasionally will retain the jaw of large makos.
This will be dried and sold for their own revenue.
Most felt that finning regulations were effective. 60% felt that if
there were no regulation regarding finning then the practise would
threaten the status of shark populations. Since the 10% regulation
has been adopted they now only retain 10%, whereas before they
would possibly have retained more depending on space availability,
current prices etc.
They all said that they have altered their fishing practices since the
regulations have been adopted. Before the adoption of the finning
regulations they would fin and dump most carcasses with the
exception of makos which were retained for their flesh.
A7.8. Practices to Deal with Caught Sharks
Most skippers interviewed try to bring the shark alongside the vessel,
then cut the line as short as possible and release the shark with the
hook in its mouth. Many however will go to great lengths to retrieve
their hook often at the expense of the shark. If the shark is small
enough then they will land it, de-hook and release or discard. A dehooker
is never used mainly because they don’t have one onboard
and thus have never tried to use one. The decision as to whether they
will retain or discard is usually based on the following: a) its size i.e. if
it is too small they will usually discard, b) if their target catch is good
they will discard (i.e. limited space availability) and c) regulations
restricting them to 10% of their target catch. One interviewee was
concerned about the safety of his crew and thus did not land large,
live sharks. Product contamination was also a concern for half of the
skippers interviewed.
118