Larval fish at time series station Helgoland Roads, North Sea, in 2003

For the larval surveys, a CalCOFI ring trawl with a 500 µm mesh net (aperture 100 cm, length 400 cm, equipped with a flow meter) was towed for 15 min from a research vessel. The samples were transferred to the laboratory, fish larvae were sorted out immediately and classified to the species level according to Halbeisen (1988) and Russel (1976). Larval abundance was normalized to larvae/m**3. Members of the family Syngnathidae (pipefishes and seahorses) were excluded from the analyses as they are not a regular part of the ichthyoplankton and occurred only occasionally after storms.