Mesozooplankton was sampled vertically with a Multinet (180 µm mesh size, 0.25 m**2 mouth opening, Hydro-Bios, Kiel, Germany). Hauling speed was 0.5 m/s. Samples were preserved in a solution of 80% seawater and 20% fixation agent (75% formaldehyde buffered with hexamine, 25% anti-bactericide propandiol), resulting in a final concentration of 4% formaline. From the fixed Multinet samples zooplankton was counted and identified to species (most copepods) or to species, genus or family level (other groups). Conspicuous, large zooplankton (> 5 mm, chaetognaths > 10 mm) was identified and enumerated from the entire sample. From the rest of the sample, at least 500 individuals from a minimum of three sub samples (2-5 ml, automatic pipette) were identified, staged and counted. This procedure allows for the analysis of abundance of common species and taxa with 10% precision and at 95% confidence level (Postel et al., 2000, doi:10.1016/B978-012327645-2/50005-0). Copepods of the genus Calanus were identified to species based on their size (Kwasniewski et al., 2003, doi:10.1093/plankt/25.1.1). Specimens other than copepods were measured and sorted into different size categories (< 5, 5-10, and 10-20 mm).