The production of Oithona similis (Copepoda: Cyclopoida) in the Southern Ocean

• Published in: ICES Journal of Marine Science
• Main Authors: Fransz, H. G., Gonzalez, S. R.
• Format: Text
• Language: English
• Published: Oxford University Press 1995
• Subjects: Articles; Antarctic; Southern Ocean; The Antarctic; Weddell; Weddell Sea; Antarc*
• Online Access: http://icesjms.oxfordjournals.org/cgi/content/short/52/3-4/549; https://doi.org/10.1016/1054-3139(95)80069-7

Seasonal variation in abundance and biomass of different instars of Oithona similis was studied for stations in the Weddell Sea and the Antarctic Circumpolar Current south of 60°S sampled in different years. Egg production was more spread over the seasons than in most calanoid copepod species and the mean stage was more constant, indicating a mixing of age classes and overlap of generations. Juvenile stages increase in abundance between October and January, but the main development of copepodids was between January and May. A minimum estimate of daily growth rate of 1.5% body weight corresponds with a development from Nauplius 1 to Copepodite 5 between 1 November and 30 May and leads to an annual Production/Biomass (P/B) ratio of 3.3. The mean population biomass in the southern waters was 150 mgC m−2 in the epipelagic zone and the minimum estimate of annual production 0.5 gC m−2. Because the contribution of the species to zooplankton biomass in the Southern Ocean may be higher than elsewhere and the annual P/B is generally much higher than in the larger calanoid species, the production of Oithona similis may be the highest of all zooplankton species in the Antarctic region.