We've had a variable summer in the Canberra region, with occasional rain and hail storms, small flash floods and lots of hot weather, but overall, the drought still reigns supreme.
Stream and lake levels remain low, and although the native fish and redfin have fared pretty well it has been devastating for the trout population.
Most trout streams are now devoid of fish or left with just an occasional survivor, and most trout anglers have been reluctant to fish the streams other than the big mountain rivers such as the Thredbo, Eucumbene and Goodradigbee. The concentration, then, has been on lake fishing, in Eucumbene, Jindabyne, Tantangara, Tooma, Khancoban and Tumut, where there have generally been plenty of trout, or in the lower regional lakes.
Canberra's five urban lakes – Burley Griffin, Tuggeranong, Ginninderra, Gungahlin and Yerrabi – have been pleasantly productive for natives and redfin. This is mostly because these lakes have stayed clear during the drought and have been easy to fish with lures and flies as well as with bait.
A lot of redfin have been taken of late, especially on Strike Pro Galaxia lures, Hogback and small Jig Spinners. Most of the fish have been the predictable small fish but there have been some spectacular catches. One group recently reported fish to 46cm, and in one magic session on Burley Griffin landed 30 fish over 40 cm in an afternoon and topped the catch with a massive fish of 53cm. That's the largest redfin recorded to date in our region.
These fish are sought after not only as fun sportfish but also for the table. The skinned and deboned fillets make great eating grilled or barbecued.
In most years, when the redfin population becomes too large it is brought back to a low level by the EHN virus. The virus is present in all of our local waters and develops as a lethal disease when the population density reaches a certain level. This most frequently happens during hot weather late in the summer. This year it appears to have affected only a small proportion of the population, but has not developed as a full-blown disease outbreak, for reasons not yet understood.
Murray cod are present in all of the local and regional lakes and have revelled in the hot weather.
My youngest son Tim tangled with a couple of the bigger monsters in Googong Reservoir recently and came off second best. The first giant took the lure then bolted, pulling maximum drag on the 8kg line with ease, until it reached a weed bed and tore the lure free. The second was even larger, dragging line off for 20 minutes before mangling the lure. It spat the Hot N Tot out when it had finished with it, with one set of trebles broken and the other squashed. It was a big fish, probably in the 40kg plus range.
We have had a lot of nice cod in the urban lakes, too. They have been taken mostly on deep divers such as Burrinjuck Specials. Hot N Tot, Stumpjumper, Predatek Boomerang and Custom Craft and on spinnerbaits. The best baits have been live yabbies, bardi grubs, wood grubs and scrubworms. The fish have been exceptionally active and aggressive in the clear water and frequently have been reported snatching hooked redfin and even golden perch in an attempt to get a free feed. Most of the fish caught are returned to the water as unharmed as possible, helping to maintain the population.
Murray cod and golden perch are stocked every two years in Canberra's urban lakes and Googong. The fish are released in areas considered to be at the upper edge of the fish's known altitudinal and temperature range.
The lakes have always been thought of as put-and-take fisheries because, although the fish survive and grow well, and produce healthy-looking eggs and milt, they do not breed. Recently, however, local ecologists have found evidence of possible slight breeding among golden perch. That's good news because it means that although the fish may not breed every year, even an occasional breeding will help maintain the population for anglers to enjoy.
Golden perch have provided good sport this season, especially on deep divers and spinnerbaits, as well as on baits such as scrubworms, bardi and wood grubs and live yabbies. A lot have also been taken on peeled saltwater prawns, which anglers now recognise as top bait for freshwater fish.Anglers resorted to trying prawns when supplies of scrub worms and tiger worms dried up during the drought and were pleasantly surprised at how successful the prawns were.
Anglers also have discovered AusSpin spinnerbaits and Chatterbaits in a big way. These lures have a lot of flash to attract fish. Also, because they ride with the hook facing upwards, they are especially useful amongst snags, rocks and weedy areas commonly found in our waterways. One angler in Ginninderra recently landed three goldens, weighing 2.3, 2.7 and 4.5kg using spinnerbaits. He said it was the only type of lure he could have used in the weedy water he was fishing.
Anglers have also discovered the joys of fishing at night with lures, especially with surface lures. Fish obviously have excellent eyesight that enables them to see lures at night. An angler recently caught a 4kg golden on a deep diver trolled at 11.30pm on a pitch dark night in Lake Ginninderra, and other anglers have reported hook-ups after dark, using just a lure or a lure fitted with a small Chemlight on the line 10-15cm ahead of the lure. Others have been catching cod on big, splashy, noisy surface lures worked in the local lakes and in the Murrumbidgee River and it's great to see the degree of experimentation going on.
Recent events have strengthened our concern that European carp may be a much more vigorous predator of other fish than we have given them credit for. The evidence is anecdotal, but pretty straightforward.
In past years anglers often laughed when an occasional carp was caught on a lure meant for a golden perch or a Murray cod. It was always a bit of a joke, a fluke, a one-off. But not recently.
During the past two summer seasons countless anglers have reported catching carp on lures. It's got to the stage where anglers now expect to catch at least a couple of carp on every outing chasing native fish. The carp take the lures in water of all depths and take it in the mouth, suggesting they are quite purposeful about it. It's not accidental: they chased the lure, caught it and grabbed it, obviously with the intention of swallowing it.
Now the obvious corollary of this is that if they chase and grab lures that look like small fish, perhaps they also will chase and grab small live fish. Valuable Australian native fish perhaps, such as golden and silver perch, Murray cod, trout cod and blackfish as well as trout, goldfish, redfin and other carp.
Given the immense population of carp in our waterways, the thought of them being an active predator of small fish is of great concern. In the past they have been reviled as bottom-feeding mudsuckers, dangerous to the stream and lake ecology and a worrying new intruder in our waterways. But as a predator they would assume greatly added importance and significance, putting stocking programs at even greater risk than redfin and other well-known predators pose. Stocking programmes such as the one where we have recently released 50,000 cod and golden perch fingerlings into our urban lakes.
I will be urging fisheries ecologists to have a closer look at this possibility and perhaps rethink some of our past appreciations of the carp's position in stream and lake ecology in south-eastern Australia. In the meantime I would appreciate hearing from anglers in other areas whether they are experiencing the same behaviour amongst the carp. Of particular interest is whether anglers find small fish in the stomachs of carp they catch and kill. Purposefully checking killed carp to see what is in their stomach could provide valuable information for ecologists to consider.
A Canberra angler with a 44cm redfin caught on a scrub worm in Lake Ginninderra.
Ben Knott took this 2kg golden perch on a Celta when he found it foraging in the shallows at Lake Burrinjuck.
3. Carp increasingly are being taken on lures meant for native fish, raising fears they may be a much more significant predator than we have previously realised.
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