Science Wednesday: ML unpacks water quality for prawns

November 3rd, 2021

Commercial prawn farmers know that managing water quality well is vital to efficient production. Ponds that are side-by-side on the same farm can yield very differently depending on the salinity, temperature, turbidity and dissolved oxygen of the water.

A new paper in Biosystems Engineering by the Digiscape Future Science Platform’s Aquaculture project, and led by Mashud Rana,  has used machine learning techniques to examine not just which water quality parameters are most important to the growth and yield of prawns in a commercial setting, but also when in the season each water-quality parameter is important:

  • The study confirmed the practical importance of water quality to prawn production: knowing the water quality history of ponds enabled classification into low-, medium- or high-growth classes with 85-88% accuracy
  • Higher water temperatures early in the growing season (i.e. spring) predicted greater yields at harvest 3 months later
  • Salinity becomes important in mid-season and especially over the last few weeks of the growing season, with lower being better for prawn growth
  • High-yielding ponds had lower dissolved oxygen late in the growing season. It’s possible that causation is the other way around here: in high-yielding ponds, oxygen is consumed more rapidly.

The precise relationships are likely to be farm-specific, but because the techniques in teh paper are data-driven they can be used to gather local insights wherever pond water quality is being monitored.