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December 29, 2015 - 12:45

We all know that introducing pathogens into our pond systems causes disease.  Some can be prevented by good Biosecurity, and this article re-iterates key points for Biosecurity.  While it is written for recirculating aquaculture (raising prawns) - the points are definitely good review for all Koi keepers!  I've highlighted the material in Bold in the article - that can be read by clicking on the title or picture above...   Further information can be found in K.O.I. Course #208 - Biosecurity, Quarantine and Record Keeping - CLICK HERE

Biosecurity in its broadest sense can be explained as practices of managing biological risks associated with food and agriculture. In prawn farming, biosecurity can be explained as the management practices implemented to prevent prawn pathogens entering and/or spreading within the production system. The main idea behind biosecurity is to protect cultured animals from contamination by infectious diseases, especially exotic ones (e.g. White Spot Syndrome Virus [WSSV] disease for Australia). Prawn farms must implement strict biosecurity practices as part of their aquatic animal health management program to ensure a successful production.

Prawn health management practices should include procedures to minimise or ideally eliminate the risks associated with the entrance or presence of pathogens in the farm. On-farm biosecurity procedures can start with routines such as filtering pond intake water, drying-out ponds with adequate soil preparation between crops, and screening post-larvae and broodstock health-status. The latter, testing for diseases, is especially important if animals are sourced from the wild. Other necessary actions to exclude pathogens from cultured stocks involves the use of quarantine when bringing wild prawns onto farms and limiting imports of live and frozen prawns for human consumption (also used for fishing bait). Avoidance of external sources of contamination in hatcheries (e.g. low quality of feeds for broodstock from unknown sources) and preventing cross-contamination of pathogens among ponds within the farm and among different farms are also important methods to ensure a biosecure production.

As a general guide for implementation of biosecurity programs the following strategy can be used:

  • Stock ponds only with post-larvae tested negative for important pathogens (especially when using wild-caught broodstock
  • Improve intake-water management to minimise contamination by pathogens;
  • Choose stocking density appropriate for pond carrying-capacity to minimise stress;
  • Reduce risks from vectors such as birds and other crustaceans (natural carriers of some prawn pathogens);
  • Restrict movement of visitors and external equipment on farm;
  • Minimise risk of contamination among ponds by restricting movement of personnel on farm;
  • Implement best animal health practices training of farm staff to detect early signs of diseases: weekly health checks including wet mounts, maintenance of good water quality, high quality feed).

Generally biosecurity programs are just implemented in prawn farms to minimise the risks associated with the entrance of exotic diseases. And usually due to the costs associated with these programs, practices are limited to implementing elementary actions (e.g. vehicle wheel disinfection prior to entrance) on hatcheries and farms. Do you need to step up your biosecurity program? We know the costs of implementing a biosecurity program should always be balanced and measured against the economic losses that future disease outbreaks could cause, not just for one single farm, but for the entire industry.

Article by Dr. Giana Bastos Gomes, Australia, posted in Veterinary Fish Medicine


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