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Patagonian
Toothfish: Fact Sheet
The Patagonian toothfish, (Dissostichus
eleginoides), and Antarctic toothfish (Dissostichus mawsonii) are deep sea
species found throughout large areas of the sub-Antarctic oceans, but
primarily in the Southern Ocean and adjacent southern parts of the Atlantic
and Indian Oceans. It is also known as Mero, Chilean Sea Bass and Black
Hake.
Toothfish
are bottom dwelling, in depths of 300 metres to 3500 metres, but move off
the bottom on occasion to feed. They are found primarily in easterly banks
and appear to thrive best near land. Consequently, the fishing grounds are
concentrated on continental shelves around the islands in the region.
This
species can be fished to depths of 3,500 metres. However this varies with
large fish of spawning age fished at a depth of around 2,000 metres in the
South Georgia and South Sandwich Islands, while around Heard Island and
McDonald Islands, toothfish are more commonly fished at depths of between
400 and 1200 metres.
The
Patagonian toothfish grows slowly and reaches spawning age between 8 and 10
years, at which stage it is about 80cm long. The fish can reach an age of
45, a maximum length of 2.2 metres and about 120 kg in weight. Its diet is
mainly based on squid, fish, crabs and prawns. The Antarctic toothfish has
very similar biological characteristics, but is thought to grow a bit slower
than Patagonian toothfish, and has a smaller maximum length (estimated at
around 1.8 metres).
The
Patagonian toothfish fishery began in the southwest Atlantic Ocean off the
coast of Argentina and the Falkland Islands in the late 1980’s and early
1990’s. Over time the fishery moved further eastwards via South Georgia,
Bouvet Island, Prince Edwards and Marion Islands, Crozet Island, Kerguelen
Island, Heard Island and MacDonald Islands, as well as at Macquarie Islands.
There are also substantial fisheries for Patagonian toothfish off the
continental slopes of Chile and Argentina.
The
Antarctic toothfish fishery began later, as the fish tend to be found only
in very southern latitudes and alongside the Antarctica icepack. The main
legal fishery for Antarctic toothfish is in the Ross Sea, called Divisions
88.1 and 88.2 by the Commission for the Conservation of Antarctic and Marine
Living Resources (CCAMLR).
Commercial
fishing of the toothfish is managed by CCAMLR around most of the
sub-Antarctic and Antarctic regions. Some of the fisheries off Territorial
Islands (e.g. Crozet Island, Prince Edwards and Marion Islands) are managed
separately by countries with territorial waters taking into account
management recommendations and approaches by CCAMLR.
In the
legal toothfish fisheries managed by CCAMLR and countries with territorial
waters, there are two main methods of fishing permitted. The most common
method is fishing by longlines (where a long ‘mainline’ is set in the water,
with many baited hooks coming off that line) and the second major method is
by trawling (where a net is towed behind the boat for short periods of
time). For all methods of legal fishing for toothfish, there are minimal
interactions with seabirds these days. This is a result of requirements for
legal operators to use mitigation devices or approaches such as:
-
No
setting of hooks during the daytime
-
No
fishing without having a bird- scaring line trailing out the back of the
boat to keep birds away from the hooks
-
No
fishing during periods when the birds are known to be feeding their
chicks (seasonal closures)
-
Boats
must use weighted longlines so that the baits and hooks sink before the
birds can grab them; and
-
Limitations on release of offal overboard at the same time as the setting
or hauling of lines (to avoid attracting seabirds when they may otherwise
be vulnerable to the baits and hooks).
Illegal,
unreported and unregulated (IUU) fishing of toothfish has been traditionally
undertaken by longline fishing boats. Of course, illegal operators totally
ignore any and all regulations and requirements designed by CCAMLR and other
countries, to protect seabirds and other species in the environment.
Fishing by
trawling does not usually harm seabirds but does tend to catch toothfish in
the smaller size range, which requires special calculations to be made at
the annual stock assessment meetings of CCAMLR to take these catches of
smaller sized fish into account.
By-catch
species (fish caught incidentally to the ‘target’ species) when fishing for
toothfish are also closely monitored by CCAMLR. There are catch limits
imposed on all by-catch species to ensure that the levels of catch do not
exceed biological or ecologically sustainable levels. Longline fishing
methods catch low amounts of skates and rays, and trawl fishing methods also
has a very low by-catch rate in the sub Antarctic, with the total by-catch
of other species less than 2% by weight of the target species, toothfish.
IUU fishing
of the Patagonian toothfish has become a very serious problem in recent
years. In some areas IUU fishing has reduced the stocks of Toothfish
markedly. Several nations have apprehended and successfully prosecuted a
number of boats for fishing illegally.
For more
information visit
CCAMLR or go to our
Links page for other interesting sites.
If you
would like more information or have any suggestions or ideas on how to stop
illegal fishing please send a message to
contact@colto.org. |
