Recommended feeding regime and light climate in live feed cultures of the calanoid copepod Acartia tonsa Dana

Understanding and optimising the parameters that controls the success for copepod cultures are the foundation for large scaled copepod cultures. Many underlying copepod culture parameters are already quantified and comprehended, but there is a lack in knowledge of optimising feeding regimes for copepod cultures. In the present study, quantification and observations on how three different feeding regimes affected Acartia tonsa cultures, in terms of development time, specific growth rate, egg production, and egg hatching success were done. The three feeding regimes where dispensed as; once a day (spiked feeding), in four equal pulses (pulsed feeding), and evenly over 24 h (continuous feeding). The feeding regimes were investigated at low food levels (similar to 200 A mu g C L-1) and at full-saturated food levels (similar to 1800 A mu g C L-1). As photoperiod may have an effect on feeding uptake and productivity, the present experiments were segregated into two light regimes, one in darkness (0L:24D) and one in light (24L:0D). Acartia tonsa exposed to fully saturate feed levels developed twice as fast as at low saturated feed levels. A significantly higher total egg production from copepods was observed, equal to 53.5 % more eggs produced in dark cultures. Also, a 2.3 % significantly higher egg hatching success was obtained when culturing in dark. Since feeding regimes do not affect cultures, it is recommended that feeding of A. tonsa should be conducted as practical as possible for the individual copepod farmer, since optimal performance will be met as long as feed is supplied in excess. Furthermore, it is recommended that cultures are kept in dark for optimal egg production and sub sequent hatching success.