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The Murray Cod is Australia's largest freshwater fish.
The largest fish ever recorded was 1.8 m in length and weighed a whopping
113.5 kg. Their average length is 44-48 cm for a male, and 48-57 cm
for a female. How well they grow depends on the food supply and on
where they live.
The longest a Murray Cod has been known to live is 49 years, but most of them do not live for
this long. |
The Murray Cod is found almost everywhere in the Murray-Darling Basin.
It has also been stocked in
lakes, dams and rivers.
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IN THE PAST
Murray Cod were found in large numbers in many parts of the Murray-Darling
Basin. |
TODAY
There are less Murray Cod in the Murray region than there were in
the late 1800s, but there are parts of the Murray where they can still be
found in healthy numbers. |
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| PLAINS |
SLOPES AND TABLELANDS |
Murray Cod live in slower-flowing rivers and creeks in the
western plains. They also live in lakes, dams and small, clear rocky
streams in the upper slopes and tablelands regions.
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| DEEP HOLES |
SNAGS AND ROCKS |
| Murray Cod like areas that have snags,
hollow logs, wood and rocks where there are places to hide. They like
slow-moving water with deep holes, and river banks with plenty of plants
growing along them. |
MATING
Female Murray Cod begin to look for warm water and become very active.
They then pair up with a male. They stay in pairs for
several days. |
SPAWNING
Spawning occurs from September - December (spring and early summer),
when the water temperature rises to between 16 and 20°C and the days
become longer. |
EGGS
Each female Murray Cod releases 20,000 - 60,000 pale amber eggs which
sink to the bottom and become sticky. They are released in fairly shallow
warm water on logs and rocks on the river bed. The male guards the nests
and probably fans the eggs. They hatch in 13 days at 16°C. |
JUVENILES
Newly-hatched young Murray Cod are 6-9 mm in length and have a large
yolk sac attached to them on which they can feed for the first few days
of their lives. |
| Murray Cod eat large quantities of smaller animals. Their diet is mainly
fish, crayfish and molluscs but
they have been known to eat waterbirds, frogs, turtles, snakes and mice.
Young fish eat shrimps, yabbies and other small aquatic animals. |
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Scientists have studied Murray Cod by fitting them with radio transmitters.
They have found that they move very little when the river flow is
low. They will fiercely defend special holes and other areas in which
they live to keep away other Murray Cod.
When the river flow increases, adults may swim upstream as far as 120 km. During high river
flows they move up and downstream, using small creeks and flooded billabongs to
find food and to spawn.
After spawning they return to the same area, and often to the same snag or deep hole.
In Lake Mulwala, Murray Cod have been known to move out of the lake and up into the inflowing
rivers to spawn. They return to the lake after spawning. Murray Cod larvae drift
downstream into the lake to settle and grow. Lake Mulwala is a good Murray Cod habitat because
it has many snags. |
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IN THE PAST
Murray Cod were the main fish caught for sale from the mid 1880s
to the early 1940s. |
TODAY
There are no longer enough Murray Cod left for commercial fishing. |
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IN THE PAST
Aborigines enjoyed eating Murray Cod. The early settlers also enjoyed
it and found it easy to catch. |
TODAY
Murray Cod are a favourite fish to catch. |
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LEGAL SIZES
Sometimes there are limits on the size of Murray Cod that can be
caught.
| ACT: |
At least 50 cm in length |
| NSW: |
At least 50 cm in length |
| Qld.: |
No limits |
| SA: |
At least 50 cm in length |
| Vic.: |
At least 50 cm in length |
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CATCH LIMITS
Sometimes there are limits on the number of Murray Cod that can be
caught.
| ACT: |
A limit of 2 fish |
| NSW: |
A limit of 2 fish (only 1 fish over 100 cm in length) |
| Qld.: |
A limit of 5 fish |
| SA: |
A limit of 2 fish |
| Vic.: |
A limit of 2 fish |
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CLOSED SEASONS
Sometimes Murray Cod can only be caught at certain times of the year.
| ACT: |
1 September -
30 November |
| NSW: |
September - November |
| Qld.: |
Anytime |
| SA: |
Anytime |
| Vic.: |
1 September -
30 November |
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BAIT
Murray Cod may be caught using lures and
bait, including yabbies, grubs, earthworms, and fish. Live fish and frogs
are not allowed to be used as bait in New South Wales and the Australian
Capital Territory. |
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| FISH HABITATS |
| The removal of snags, logs and wood from rivers means that there are
less places for Murray Cod to live. |
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| FISH MOVEMENT |
| Dams, weirs and locks make it difficult for Murray Cod to move from
one place to another. |
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| WATER FLOW |
| Since the river
regulations have been in place, floodplains have become smaller
and flood less often, so there is less food for young Murray Cod. |
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| FISHING |
| There may have been some overfishing of
Murray Cod before the 1930s. |
Murray Cod have been bred artificially since 1972 and government and
private hatcheries now
supply young
fish for stocking. They are released when about 35 mm long and 5-8
weeks old.
Since 1997, over 280,000 young Murray Cod have been released by New South Wales Fisheries into
lakes, dams and rivers. Large, but unknown numbers were also released by private hatcheries.
A few fish
farms have begun to grow young Murray Cod, mainly to supply restaurants. |
RECOVERY PLANS
There are no particular recovery plans
in place for the Murray Cod but stocking with young fish will probably continue.
Improving the river environment will help the Murray Cod, especially the
re-snagging of rivers and the building of fishways. |
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