Feeding and reproduction of Calanus finmarchicus during non-bloom conditions in the Irminger Sea
Simultaneous ingestion and egg production experiments were conducted with female Calanus finmarchicus in April/May and July/August 2002 in the Irminger Sea. Experimental animals were provided with natural microplankton food assemblages and incubated under in situ conditions for 24 h. The quantity of...
| Published in: | Journal of Plankton Research |
|---|---|
| Main Authors: | , , , |
| Format: | Text |
| Language: | English |
| Published: |
Oxford University Press
2006
|
| Subjects: | |
| Online Access: | http://plankt.oxfordjournals.org/cgi/content/short/fbl047v1 https://doi.org/10.1093/plankt/fbl047 |
| Summary: | Simultaneous ingestion and egg production experiments were conducted with female Calanus finmarchicus in April/May and July/August 2002 in the Irminger Sea. Experimental animals were provided with natural microplankton food assemblages and incubated under in situ conditions for 24 h. The quantity of food consumed was significantly related to the concentration of prey cells, with total daily ingestion rates ranging between 0.6 and 8.1 µg carbon female-1 d-1, corresponding to carbon-specific rates of between 0.6 and 4.7 % d-1. Egg production rates remained relatively low (0.3 - 11 eggs female-1 d-1) during both periods of investigation, and were not influenced by food availability. The data were used to construct energetic budgets in which the microplankton carbon ingested, including ciliates, was compared to the carbon utilised for egg production and respiration. These budgets showed that ingestion alone could not provide the necessary carbon to sustain the observed demands for growth and metabolism. Although ciliates constituted > 80 % of the total material ingested at times, they were not sufficient to provide the metabolic shortfall. Indeed, the females were typically lacking around 5 µg of carbon each day, approximately 5 % of their carbon biomass. Our results highlight the possible importance of internal reserves in sustaining reproduction in C. finmarchicus during periods of food scarcity |
|---|