Using the ProtoCol 3 Colony Counter to Quantify Egg Numbers from the Fish, Short-Term Reproduction Test

SETAC EU 2022 -- The OECD 229 Test Guideline (Fish Short-Term Reproduction Assay) requires daily assessment of reproduction as one of the measurements of test item effect for potential endocrine disruption. The requirement is for a daily egg production at least 10 eggs per female per day in the control. For a valid test, this equates to a minimum of 3,360 eggs from the control group alone. Experience has shown that with fathead minnows, egg production can be considerably higher than this with 40-60 eggs per female per day as a routine occurrence. To compound this, a typical test requires a minimum of 80 females per test; therefore, often double this number of fish are usually used for monitoring egg numbers during the pre-acclimatisation stages. Many labs estimate the number of eggs produced. However, we wanted a scientifically robust method of counting. Given these higher number of eggs, it was decided that a manual counting procedure would be extremely time consuming and potentially inaccurate and therefore an automated approach was adopted.