Pelagic Biomass Survey on the Africana Voyage 108, November 1992

The Pelagic Spawner Biomass Survey was conducted on the Africana Voyage 108 from 05 November to 02 December 1992. The objectives of the survey were to get an estimation of the biomass and population length structure of anchovy, pilchard and round herring off South Africa by means of echo-integration and midwater trawling; estimation of anchovy biomass by means of the egg production method, and trial estimation of pilchard biomass by means of the egg production method; description of distribution and behaviour patterns of commercially harvested epi-pelagic and meso-pelagic fish, and the influence of oceanographic variables on these; collection of biological data on reproduction, condition and diet of pelagic fish species; to determine phytoplankton biomass in the nanophytoplankton (<10 µm) and netphytoplankton (>10 µm) size-classes in surface waters; to obtain information on the distribution and abundance of meso-zooplankton; and lastly to estimate secondary production rates of adult copepods using the egg production method. If time permitted, experiments were to be set up to determine growth rates of the juvenile stages of the dominant copepod species (Calanus and Calanoides).