Amoebic Gill Disease is the leading cause of mortality and loss of aquaculture production which plagues the Tasmanian salmon industry in recent years. The financial cost of AGD is estimated at approximately 14% of gross production equating to $15.4M annually. Recently, a combination of warm water temperatures, reduced rainfall and increased production on farms has resulted in a perceived decrease in the effectiveness of current freshwater bathing practices in controlling AGD. Freshwater baths, the usual treatment for treating AGD, appear to be less effective at treating the disease and more frequent baths are required compared with previous years. Recent studies by the Principle and co-investigators (Clark et al. 2000) have shown that freshwater bathing does not reliably kill all of the Paramoeba on salmon gills and re-infection can occur in as little as 10 days post bathing. Since current treatments are proving inadequate, more effective treatment strategies are required for the Tasmanian salmon industry to sustain current production levels.
Project number: 2000-266
Budget expenditure: $86,392.00
Principal Investigator: Mark Powell
Organisation: University of Tasmania (UTAS)
Project start/end date: 29 Oct 2000 - 2 Dec 2002
1. Identify water chemistry characteristics that enable Paramoeba to tolerate freshwater bathing.
2. Identify potential additives/supplements to the freshwater bath that promote effective killing of Paramoeba. These treatments must be environmentally friendly and fall within guidelines for the use of compounds for food and within drinking water.
3. Identify the effects of water movement on the clearance of Paramoeba from salmon gills and efficacy for freshwater treatments.
4. Test candidate treatments on a pilot scale examining:Clearance rate of Paramoeba from the gills of salmonRe-infection rate of treated fish.
5. Make available successful treatments and treatment strategies will be available for testing on a commercial scale and for adoption by the industry.
Author: Mark Powell