construction and refurbishment of earthen irrigation channel banks

Thus, control of carp by draining channels without complete emptying, isunlikely to be effective on its own.23.5.5.2 FishingFishing competitions for carp have become popular in recent years but have anegligible impact on carp populations. However commercial fishing and targetedelectro-fishing can reduce the carp population in a particular area if carried out ina strategic manner.Commercial FishingWhile commercial harvesting is not feasible on a widespread basis, it may beused as a form of carp management to reduce damage caused by carp in somerestricted areas. At low densities, commercial carp harvesting is not profitableand so will often fail to reduce carp densities enough to meet damage controlgoals.The largest carp harvester/processor in Australia (Gippsland Lakes, Victoria)processed 900 tonnes of carp in 1999 for domestic and export markets, with atarget of 1000 tonnes for the export market alone in 2000. Retail prices for wholecarp are up to $7 per kilogram in some Sydney shops. There is some potential toincrease the value of carp with further processing (smoked and canned fish etc).However, currently much of the commercial catch is used for low-value productssuch as fertiliser (15 cents per kilogram) and crayfish bait (50 cents perkilogram).There is a widespread belief that commercial use of carp can solve the carpproblem. The reality is that carp are currently a low-value product, which limitscommercial offtake to areas that have high carp densities and good access towaterways and markets. Nevertheless, there is some potential to increase therecreational and commercial removal of carp by promoting carp as a target fishand increasing the value of carp products.Several commercial ventures have been attempted to process carp into fertiliser,pet food etc. However commercial fishing of carp across the Murray-DarlingBasin is not expected to have any significant effect on carp numbers as currentlyless than five percent of their waterways are commercially fished. This could beincreased if there was a market developed for carp. However, if a commercialventure proves successful, there would be pressure to maintain a threshold levelof carp rather than eradicate them.Electro-FishingThis process involves an electro-fishing unit mounted in a boat. An electriccurrent is discharged into the water through electrodes suspended on a boomfrom the boat. Fish are temporarily stunned (approx 30 seconds), float to thesurface and are then picked up using a hand net. Any native fish can then bereturned to the waterway while the carp are destroyed.electro-fishingPhoto 23-2Electro-fishing unit mounted in boatConstruction and Refurbishment of Earthen Channel Banks August 2002 - Edition 1.0 23-21