Given the strange weather of the past year or so, it would be easy to accept that climate change actually is a real phenomenon. And that it is now here.
Funny things have been happening. The weather patterns have been most uncharacteristic, not just in the Canberra-Monaro district but in many other parts of Australia where I have been in contact with other reliable weather-watchers. And it has now gone on for too long to be able to just dismiss it as a short-term peculiarity.
Firstly there has been the rainfall. We have now gone six years without regular rain. When it has rained it has either been a short, sharp thunderstorm or a pathetic drizzle and I can't remember when it rained for more than a few hours at a time. That has resulted in a massive rainfall deficit, a drought of climactic proportion.
Remember when it used to rain regularly, heavily and sometimes steadily for several days at a time? Remember when rivers flooded, broke their banks and swept away all the algae, silt and accumulated plant material?
Remember when lakes and reservoirs filled to overflowing and landholders had to move pumps, irrigation equipment and livestock to higher ground? Remember when the fish could undertake easy upstream or downstream migrations in abundant stream flow?
Remember when stream flows were so great that you didn't dare try to wade them and in many instances were so strong that you simply couldn’t fish them?
Those things haven’t happened around here for many years and there is no long-term prediction that they ever will again. And while that might be an over-simplistic generalisation with only just over 200 years of weather recording on which to theorise, there is growing evidence that we could be facing a whole new permanent pattern of climatic events that require us to think ahead as to what future our recreational fisheries face.
Take our trout streams, for example. Most have suffered from extreme water shortage for at least six years. Many have dried up or reduced to isolated pools full of thick weed and algal sludge. The fish have died from lack of oxygen, lack of food and temperature stress.
In their depleted condition the streams further deteriorate physically, chemically and biologically through trampling by livestock and accelerated erosion resulting from short, sharp thunderstorm runoff.
Each time rain generates what looks to be a suitable stream flow it is tempting to consider restocking with fast-growing rainbow trout or the hardier brown trout, using stock produced in anticipation each year by Government or hatcheries.
Every now and then we take a gamble and stock some streams with fry or fingerlings but in most cases the fish die and a lot of Government and volunteer effort is wasted. All we gain is the experience of when not to stock.
In the hatcheries the unused fish grow bigger, become more expensive to feed and harder to move about and eventually are lost or dumped in a lake, whether they are required or not. And every lake has a limit to the number of fish it can carry and dumping does not necessarily mean good fishing. Take a look at the proportion of stunted fish in Lake Eucumbene today.
So what do we do with the trout streams? We continue to manage and stock the higher-country streams where water levels are guaranteed because of higher rainfall, yearly snowfall and lower air temperatures. These especially include streams connected to lakes, where the fish can migrate at will between secure and less-secure locations. These at present are our only reliable trout streams and may well be the only ones left in future.
The others may well become ephemeral waterways generally devoid of trout. Most will not be able to support continuing populations of silver perch, golden perch, catfish, trout cod, Murray cod or other native sportfish species and even redfin and carp could struggle.
This would represent a massive diminution in our recreational fly, lure and bait fisheries and put increasing pressure on increasingly fragile lake fisheries.
So what is the future of our lake fisheries? In years past we thought of them as somewhat inviolate. Despite the fact that most were man-made we saw them as permanent, always full of fish and with an assured water and food supply. Then came the drought, and with it an increasing demand for water for irrigation, for domestic use, for power production and for environmental flows.
Initially we got used to occasional reservoirs being drained to low levels but things always bounced back and the fishing improved again. That was the norm and we relied on commonsense prevailing, even though occasional bad decisions were made.
Now it seems that commonsense has gone out the window. Decisions are being made on the basis of panic, bureaucratic isolation from reality, political greed for survival and ignorance of the social value of recreational angling as well as the need for conservation of the only wild populations of Australian native fish left in the whole world. And some of the best populations of trout left on mainland Australia.
Reservoirs everywhere are being drained to extinction or near- extinction, irrespective of the social and other losses. In just our part of the world Pejar Reservoir, one of the most productive trout lakes in Australia, was drained to extinction. Many thousands of fish were killed and today it stands fishless, admittedly replenished since recent rain.
Not far away, Wyangala and Burrendong reservoirs were drained to a ludicrous 4% capacity. No one knows what the impact was on their fish because Government lacks the resources to investigate properly but anglers’ reports suggest that a significant proportion of golden perch, silver perch, catfish, Macquarie perch, Murray cod and trout, especially the larger specimens, have perished. The only winners, in terms of survival, could well be redfin and carp.
In Burrinjuck, once probably the best mixed native-exotic fishery in Australia, the trout and Atlantic salmon have gone, the Macquarie and silver perch population is minuscule and the impact on the golden perch and Murray cod remains unknown. Admittedly, not all fish losses have been attributable only to drought, but drought certainly exacerbates those losses.
Look at what else we lose by taking the water away. The birds, lizards, snakes, tortoises, platypus, water rats, plants and other animals that have enriched our lives and we would have hoped would do the same for our children.
Lost through drought, no doubt, but made worse by mismanagement by people totally unqualified to do so – our politicians. The sooner they step out of the grandstanding limelight of political fame and desperation for re-election and let the real managers, the water, fisheries and other resource scientists get on with the job of managing, the better.Reads: 679