Influence of food organisms on the development and culture of pelagic copepods
- A. Nassogne1
© Biologischen Anstalt Helgoland 1970
1. Growth rates of populations started with adultEuterpina acutifrons fed on 16 different unicellular algae, and 2 mixtures of these algae, were compared. Only algae of medium size can support growth rates as high as those obtained in the mixture. Smaller algae (6–7 µ) or wider ones (> 16 µ) give lower rates or do not support adult survival.
2. Of 5 algae tested, only those of medium size support all developmental stages from egg to adult ofEuterpina acutifrons. These results show that the size of food is one of the factors limiting the production of copepods under laboratory conditions.
3. By feeding adult females ofEuterpina acutifrons onPlatymonas suecica at various concentrations, it was demonstrated that, when the food concentration increases, the rate of ingestion and the egg production of the copepod increases thereby reaching a plateau, while the rate of filtration decreases.
4. The same relation is found for the 5 algae tested in regard to ingestion and filtration activities. However, for the 5 algal species, the concentration at which the plateau is reached, and the value of ingestion at this plateau, are quite different.
5. When feeding femaleEuterpina acutifrons in excess unicellular solutions of the 5 algae or a mixture of all the algae used, egg production and adult life span differs according to the type of the food algae. Algal species which result in low egg production and short adult life span are most intensively ingested in terms of biomass.
6. By increasing the number of algal species and their concentration in the culture solution, we were able to cultivate some additional pelagic copepods through several generations.