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Orange
Roughy: delicacy from the deep
Preview
Orange roughy live in a world which is cold, dark and has
a water pressure 80-100 times that of water at the surface.
 Up
until about 30 years ago orange roughy managed to survive
away from human intervention. But modern technology has now
enabled us to reach more than a kilometre under the sea to
harvest orange roughy as one of New Zealand's richest fisheries.
| Main
features |
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Reddish
body and fins |
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Large,
bony head |
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Large
eyes |
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Oil-rich,
with waxy layer below the skin |
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Distribution
Found around the world, including the North Atlantic, where
they were first discovered in 1889. Present in large numbers
in specific locations around New Zealand between 800-1500 metres
depth.
Lifespan
Slow-growing, long-lived fish, thought to live up to 150 years.
Size
Most fish caught are 30-40 cm long and weigh between 0.9-1.9
kg. Maximum size is 50 cm and 3.6 kg.
Diet
Mainly prawns, fish and squid.
Breeding
Fish do not begin to breed until they are 25-30 years old.
Each female carries about 22,000 eggs per kilogram of body
weight, less than 10 percent of the average for other species.
The eggs are 2 mm in diameter.
 Fish
gather into huge schools for spawning each year from late
June to early August. The main spawning grounds around New
Zealand are the Challenger Plateau, Cook Canyon, Puysegur
Bank, North Chatham Rise, Ritchie Bank and East Cape at depths
of between 700-1000 metres. The underwater terrain is rugged,
with hills, pinnacles and canyons.
Fertilised
eggs drift towards the surface and hatch into larvae after 8-9
days. It is not known where the juveniles live. The fish are
not usually encountered again until they are caught as adults
by commercial fishers.
The
orange roughy fishery
Orange roughy is one of New Zealand's most valuable export species.
Most are caught on the Chatham Rise.
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Click for larger image
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Its firm, white flesh and delicate shellfish-like flavour have
made it highly popular around the world. The carcass and skin
are rich in oil, which could be developed as a substitute for
the oil obtained from sperm whales.
Orange
roughy was virtually unknown in New Zealand waters until the
1970s. Commercial fishing did not really develop until 1979.
Fisheries have also developed off Australia, the United Kingdom,
France and Nambia.
The
main fishing season is from June to August, during
the spawning season, when fish come together in aggregations
and are easier to catch. It is only with the use of
high technology that the fish can be located and caught.
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Fishing
grounds and known spawning areas. |
Orange
roughy catches peaked at around 54,000 tonnes in 1988/89. Since
then catch rates have declined as quotas have been reduced to
establish a sustainable catch level. In 1997/98 16,664 tonnes
were caught, in 1995 this fetched $154 million on the overseas
markets.Exports are now down to around $79 million in 1998.
Managing
the fishery
Since quotas for orange roughy were introduced in 1986, scientists
have found that the fish breed later and live much longer than
most other fish. This means they are also much less productive
than other fish species and stocks take a long time to recover
from heavy fishing pressure.
 As
a result the Government has reduced the Total Allowable Commercial
Catch for orange roughy in recent years. However, there is
concern that orange roughy are still being fished too heavily
to allow stocks to rebuild to optimum size. Orange roughy
are being managed on a stock by stock basis (Chatham Rise,
Challenger Plateau, etc). Some of these stocks are genetically
distinct. Because orange roughy are so important to our economy,
a lot of effort is put into researching the species.
For
more information click on any link below.
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