Nielsen, T. National Environmental Research Institute,
Satapoomin, S. Phuket Marine Biological Center/ University of Copenhagen,
Hansen, B. Roskilde University,
Sabatini, M. Instituto Nacional de Investigación y Desarrollo Pesquero,

The importance of small copepods are often severely underestimated due to the use of coarse nets for sampling. Based on sampling with a 30 micron net, we have re-evaluated the role of the small cyclopoid copepod Oithona in the North Sea. The surprising finding was that Oithona on average is responsible for 40 and 13 % of the annual copepod production in the southern and northern North sea, respectively. Measurements of egg production rates covering an annual cycle and from mesocosms experiments, documents that the egg production rate of Oithona, in response to changes in the potential food, is less variable than the egg production of the co-occurring calanoid copepods. The results from Danish waters are compared with annual studies from two other marine ecosystems; 1) The Arctic Disko Bay, Western Greenland , characterised by high copepod biomass and low diversity and 2) The Tropical Andaman Sea, Thailand , with low biomass and high diversity. In both systems Oithona contribute significantly to standing stock and production. The observed variation in biomass and egg production rate is compared with calanoids and discussed in relation to hydrography and potential food.
Day: Tuesday, Feb. 2
Time: 02:30 - 02:45pm
Location: Hilton of Santa Fe
Code: SS23TU0230H