Rotifers are microscopic zooplankton used extensively in aquaculture because of their high reproduction rate, optimal size for larval fish and good nutritional profile. Rotifers are essential for the first feeding of many species of marine finfish larvae. Common rotifer culture methods include indoor batch cultures and outdoor pond cultures. However, both methods face a common issue of culture instability where the rotifer population could collapse overnight. In addition, an outdoor pond culture has a larger footprint compared to an indoor batch culture, an important factor in land-scarce Singapore. A continuous rotifer culture method based on a recirculating aquaculture system developed at SFA’s Marine Aquaculture Centre and the management protocols adopted to maintain stable rotifer growth is described here.
Maintaining desirable levels of rotifer population density at different stages of the continuous rotifer culture is also critical for a successful production. Harvesting, feeding, or initiation of new culture for upscaling depends on the density of the culture, which requires counting of rotifers under the microscope. To reduce manhours and simplify the counting process, an artificial intelligence (AI) assisted rotifer counting mobile web application was developed. Pictures of the rotifer samples taken with a phone camera just needs to be uploaded onto the server hosting the AI-assisted counting software for analysis, drastically reducing the time required to deduce the rotifer density in any culture .
With the ability for stable indoor continuous rotifer production coupled with technology to reduce reliance on manpower, rotifers can be produced intensively and consistently on a small footprint to support large-scale hatchery production.