Cultivation ofCalanus helgolandicus under controlled conditions
- G. A. Paffenhöfer1
© Biologischen Anstalt Helgoland 1970
1.Calanus helgolandicus was grown from egg to adult in agitated seawater cultures at 15° C in the laboratory.
2. The chain-forming diatomsChaetoceros curvisetus, Skeletonema costatum, Lauderia borealis and the dinoflagellateGymnodinium splendens were offered as food. The concentration of food, resembling phytoplankton concentrations found in the ocean off La Jolla, ranged from 28µg to 800µg carbon per liter.
3. Depending on food quality and food concentration, the time from hatching to adulthood lasts between 18 and 54 days. Mortality from hatching to adulthood ranges from 2.3% to 58.2%. The length of adult females is directly related to the amount of food offered; it ranges from 3.03 mm to 3.84 mm.
4. The sex ratio in different batches of laboratory grown copepods varies considerably. The largest percentage of males (about 25%) was obtained withLauderia borealis orGymnodinium splendens as food source.
5. The fecundity of females grown and fertilized under laboratory conditions averages 1991 eggs per female with a hatching percentage of 84%. These values are close to those obtained from spermatophore-carrying females from the ocean (2267 eggs per female; hatching percentage 77%).