Distribution and trophic links of gelatinous zooplankton on Dogger Bank, North Sea

The ecology of small, gelatinous zooplankton is not integrated into management of Dogger Bank (54A degrees 00' N, 3A degrees 25' E to 55A degrees 35' N, 2A degrees 20' E). In pursuit of this goal, gelatinous zooplankton and their potential prey were sampled along a transect across the bank on June 10-16, 2007. Eleven species of small medusae and ctenophores were collected, with six abundant taxa occurring in greater numbers below the thermocline and in the shallower, southeastern portion of the bank. There were no statistically significant diel changes in distribution. In contrast, potential prey were distributed more evenly across the bank and throughout the water column. Isotopic analyses revealed that gelatinous zooplankton fed on both smaller (100-300 mu m) and larger (> 300 mu m) mesozooplankton, but also potentially on each other. These ecological insights suggest that small medusae and ctenophores should be integrated into sustainable management of Dogger Bank.