2011/728 Enhancing survival in aquaculture (specifically P. monodon) by creating a Heterosigma algal identification unit

By Richard Smullen

Australian Prawn Farms has had numerous problems with Raphidophyte algae that is believed to be Heterosigma. This species is responsible for several mass mortality events over a number of seasons, attributing to approximately 5-10% lower survival across the farm. Australian Prawn Farms has established a laboratory test based on a reaction between pond water samples and a known ratio of acid. This reaction causes mucus production by Heterosigma exclusively allowing the algae species to be detected without microscopic identification. Although this test allows detection of the algae at low concentrations, i.e. early on in the bloom stage, due to staffing and time limitations as well as the rapid rate of bloom development it is difficult to test at the frequency required to detect initiation of a bloom. This project will investigate automation of this testing protocol which is vital if Heterosigma is to be detected at a stage early enough to implement management techniques to prevent/reduce mortalities.

This project aimed to enable farms to detect Heterosigma very early and thus adopt a management technique to combat it before mortality occurs. It is envisioned that a 5-10% per annum increase in survival will occur if able to test and detect this algal species 24hr/day .

Project Objectives

1. Elucidate presence of mucus production in available raphidophyte species.
2. Determine detection limits of prototype for all mucus producing raphidophytes.
3. Determine minimum mesh screen size of prototype to allow common algae species to pass through.