The fish were obtained by tender from a NSW commercial hatchery, using funds provided by the National Capital Authority, the ACT government and local angling clubs and are expected to grow quickly to catchable size. That is, if they can escape predation by the considerable population of carp and redfin in the lakes.

The fish were allocated according to a previously publicised territory fish stocking plan, with 29,000 going to Lake Burley Griffin and 39,000 to Lake Ginninderra They will provide a welcome boost to recreational fishing stocks and also play an important role in controlling pest or undesirable animals such as mosquitoes and leeches.

They also apply significant pressure on pest fish species such as redfin and carp, which they eat throughout the year.

Despite their popularity as a sport fish, few Murray cod are killed by anglers. Most are released immediately after capture, to provide further sport. As a consequence the average size of the fish captured has increased and fish over the magic one-metre mark are becoming increasingly common.

In Burrinjuck Reservoir, where a similar situation exists, 16 cod over one metre were taken in just one week recently.

Lake Tuggeranong off limits

The bad news is the closure again of Lake Tuggeranong to recreational use because of excess levels of blue-green algae. This means that the lake cannot be used for swimming, boating, fishing or any other form of body contact and is a disgrace.

The lake was built and is maintained at considerable expense with scarce public funds and yet there it sits, once again hopelessly polluted and unavailable for public use.

Beware what you eat

Anglers travelling further afield in NSW and Queensland during the holidays are warned to be careful of fish eaten, particularly because of the risk of ciguatera.

Ciguatera is a nasty nerve condition caused by the toxic algae Gambierdiscus and is undetectable until the fish is eaten. It is becoming increasingly common in eastern Australia. Older and larger tropical or northern fish species are the most likely to be affected.

The golden rules to avoid it are don't eat large fish, don't eat much of any one fish and stop eating any seafood if early symptoms, such as tingling of the fingertips or numbness of the lips, develop. Spanish mackerel, one of the most common species affected, was recently responsible for four new cases in NSW.

The Sydney Fish Markets no longer allows the sale of mackerel over 10 kilograms. Other fish to be wary of during the holidays include coral trout, red emperor, wrasse, trevally, queenfish, red bass, chinaman fish, groper, barracuda and kingfish.

Lakes worth a look

The mountain trout lakes are expected to be crowded during the Christmas break but some good fish are showing. Fly anglers in East Jindabyne reported catching some nice browns, small rainbows and a nice brook trout and trollers have done reasonably well.

Bait anglers report small rainbows are taking Power Bait and scrub worms during the day. Best flies have been Pheasant tail nymph, Blue Dun and midge balls during the day and mudeye patterns at night. Best lures have been Tasmanian Devils and Strike Pro, Halco and Rapala minnows.

Eucumbene also is fishing better than in previous weeks, with some nice browns at Providence Flats and the mouth of the Eucumbene River and a scatter of small rainbows elsewhere.

Tantangara has been the best fishery, with nice browns on bait from the shore and on loch-style fly fishing from boats. One group recently landed eight browns and rainbows to four kilograms fishing scrub worms from the shore near the dam wall.

Coast clearing

Inshore fishing has been hard at the coast because of recent floods but is improving as the water clears.

There were bream, blackfish and flathead on nippers and lures in the Bermagui River, bream and blackfish at Tuross and nice flathead on bait and lure in Wagonga Inlet. A few whiting have shown on beach worms on the beaches and salmon are slowly showing again around Bingi, Blackfellows and One Tree Point. Good blackfish have been taken on weed and nippers at Burrill Lake.

Offshore, there are rat kings in numerous locations, especially inside Jervis Bay and on the southern end of The Banks. Larger fish have shown intermittently at Montague Island on fresh squid and live yellowtail. Albacore and occasional yellowfin have surfaced out wide and the first marlin of the season are expected soon.

All of the FADS (fish aggregating devices) have been installed and should attract dolphin fish and other species as warm water streams down from northern areas.

Bryan Pratt is a Canberra ecologist.