Naupliar development times and survival of the copepods <i>Calanus helgolandicus</i> and <i>Calanus finmarchicus</i> in relation to food and temperature

We measured egg hatching times and stage specific naupliar development times of the key calanoid copepods Calanus helgolandicus and C. finmarchicus in response to temperature, food quantity and food type. Calanus helgolandicus development times decreased with increasing temperature and when fed Isochrysis galbana (4.4 μm ESD) rather than Prorocentrum micans (29.5 μm ESD). Nauplii needed higher food carbon concentration to develop past the first feeding stage (N3) when fed I. galbana compared with P. micans. At low food carbon concentrations nauplii developed more slowly past N3 than at more saturated levels. The survival of nauplii fed P. micans increased with temperature, but starved nauplii survival decreased at higher temperatures. We parameterized a temperature-dependent model of development for both species which fitted the observed stage durations under non-limiting food extremely well and demonstrated that C. finmarchicus develops faster than C. helgolandicus. Further data are needed to clarify the effect of food-temperature interactions on development rates.