D.6.1 | Rotifer Production: Methods

Continuous vs. Batch

(equilibrium feed chemostat vs. progressively increasing density and feeding)

Continuous and batch rotifer system are simply two methods of managing the same rotifer population dynamic. In continuous systems you harvest 25% to 45% of the culture every day and “re-inoculate” with the remaining 55-75% of your culture volume. In batch system you harvest every 3-5 days and re-inoculate with 10-30% of your culture volume. While rotifer growth dynamics may be the same, there are significant differences in how you manage continuous and batch systems.

Population Dynamics – Continuous and Batch systems

In theory, rotifer population dynamics of continuous system and batch system are the same.


  • Set a harvest rate goal
  • Assuming a harvest of 40% of the culture per day, the rotifer culture must increase its population 66.7% per day
    • (100% / (100%-40%)) = 166.7%
    • Rotifer growth rate is 2.15% per hour.
    • Median rotifer age is 33 hours.
    • Average age is 46 hours.

Batch Culture:

  • Set a growth rate goal
  • Assuming a growth rate of 66.7% per day
  • Rotifer growth is still at 2.15% per hour
  • ½ of the rotifers are still produced in the last 33 hours
  • Average age is still 46 hours

Table D.4: Population Dynamics with Continuous and Batch Harvest systems equivalencies for different harvest rates from a continuous system:


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