The Goulburn River is going
to be different this summer. The lake is going down
to 3% and the remaining water will be used to maintain
environmental flows. This will occur in mid January.
This means low flows at the hottest time of year with
the potential for warm water to be drawn from the low
lake, further warmed as it is held in the Pondage and
then entering the river with very little flow. Probable
temperatures up to 25 degrees will impact on the trout.
Should there be a prolonged period of hot weather (most
likely at this time of year) the weaker specimens will
begin to die.
The last time we had a
situation like this was two years ago. The lake had
fallen below 12% and a spell of four days of hot weather
followed. The temperature of the river rose to 25 degrees
and stayed there for four days before a cool change
brought the temperatures down a few degrees. It wasn't
until four days later that we found four fish carcasses
stuck in the weed upstream from Thornton.
They were partially decomposing
and have obviously been in the water for about a week.
These were the weak and vulnerable fish I spoke of.
Others survived well, seeking cooler spots, cold water
in the depths of the pools, mouths of creeks or cool
water springs emerging from underground seepages beneath
the gravel. This was in March, much later in the season
when the nights were beginning to cool. This time it
The potential is there
for a serious disaster with larger numbers of dead fish.
As a recent meeting with
NRE at Alexandra the possible scenarios were examined.
Contingency plans were made for the worst possible outcomes
just in case they did eventuate. Depending on rainfall,
and weather patterns, the surface temperature of the
lake can rise to 25 degrees and be drawn from the power
station into the pondage. The pondage will be streamlined
i.e. drawn down to the old river course so that the
water flows directly through the pondage into the river,
to prevent further heating of the water.
If the Hydro Power Station
is to be used they will keep the pondage 1/3 full. This
could mean a large fish kill in the pondage as the rotting
weed and stillwaters with high temperatures take their
Between now and until mid-January
the fishing has and will be the best we have seen for
years. The river is currently firing and the trout will
revel in the warmer temperatures. This stimulates their
metabolism and combined with the large spring hatches
and large population blooms of insects, the fishing
will continue to be good.
Unfortunately when the
temperature rises above 20 degrees the opposite will
happen. Warmer water holds less oxygen, fish need oxygen
to metabolise and so very quickly they become lethargic.
Eating requires oxygen to metabolise food so the fish
cut back oxygen requirements by eating less. They very
quickly seek relief by moving to the coolest parts of
the river, shade, cold water streambed springs and cooler
We expect large numbers
of fish to move out of the Goulburn into Snobs Creek.
The Rubicon and Acheron Rivers will become the repositories
of our future Goulburn stocks. We would highly recommend
that these stocks in the Rubicon be protected by a voluntary
code of catch and release. In the latest survey more
than 50% of all anglers practice catch and release on
the Rubicon already. We would suggest that these are
all the fly fishers.
Hopefully the floods of
next winter will flush these fish back into the Goulburn
to be the foundation stock for the recovery of the Goulburn
NRE-Fisheries have no plans
to restore or have a recovery plan in place for 'alien'
species so it will be up to us to restore our own trout
fishery when the time comes.
There are vast numbers
of 'doom and gloom we'll all be ruined' merchants and
whilst there is the potential for disasters there is
also the potential for some survival as well. After
extensive consultation with MAFRI (Marine and Freshwater
Research Institute) we are convinced that some of the
best year class of fish will survive, but also many
What concerns us more is
the unwillingness of NRE-Fisheries to accede to the
need for a plan for the restoration of the fishery.
To this end we have recently spoken to Candy Broad Minister
for Fisheries and Cheryl Garbutt NRE who have listened
carefully. We expect a response from them both soon.
We need you support for
issues such as restoration programs or catch and release
for the Rubicon, watch this space. We will be making
strategic assaults on these issues later. Today the
river is 15 .2 degrees and the lake is 21.5% of capacity
with 9.5 part per million oxygen content in the water.
Perfect for spectacular hatches and fishing. This should
continue through the next month until the lake levels
Meanwhile, enjoy some of
the best fishing in ten years.
STOP PRESS Update
and Progress Report 16th December, 2002
Since this article was
written we have had some significant rain across Victoria
which has reduced the demand for water for irrigation.
Add to this the cost of water being doubled and allocations
restricted further to maximum 50% of entitlement. Farmers
have responded by selling large numbers of stock and
curtailing their operations.
As a result the lake has
been held to 19% full which is much better than anticipated
at this stage. Projections indicate that at the present
reduced rate of consumption the lake will last until
at least February sometime - a much better outcome than
previously predicted. Full flow rates will be maintained
throughout January with 3,500 meg being released daily.
While temperatures will get hot, at least they are saying
that now we should get through most of summer ok. If
the lake had run out after Christmas as some had forecast
then we would have been looking at a situation far worse
than the one that confronts us now.
This has been a salutary
scare for the water managers who have had to urgently
devise strategies to cope with the lower than normal
Flow rates will drop from
3,500 to 2,000 to 1,500 in mid feb. Lower flow rates
and higher temperatures will impact on the amount of
dissolved oxygen and this causes fish to reduce their
metabolism by not feeding as much
So we will all wait to
see what actually happens this summer with some anxiety.
Hopefully things will not be as bad as they have the
potential to be in the Goulburn River. If we can get
the fish through the worst of it we will be ok. Losing
all the brood fish would really set back the fishery
a long way.
So bring on the cooler
nights of March and lets all hope that we get a cooler
than usual summer.
More detail as it comes
- Antony, David and Geoff