Controls on the vertical distribution of meiobenthos in mud: field and flume studies with juvenile fish

Abstract

We investigated the influence of the bottom-feeding fish Leiostomus xanthurus on the vertical microdistribution of meiobenthos. Sectioned cores, which were taken at low tide in the field, did not exhibit evidence that fish, which had foraged 3 to 4 h earlier, affected the vertical distribution of meiofauna. However, field cores collected where fish were feeding did show reductions in meiofaunal abundances in the top 2 mm of sediment. Controlled flume experiments also showed that fish influence the vertical distribution of meiofauna. For copepods, copepod nauplii and foraminiferans, reductions in abundances occurred in the top 4 mm of sediments due to fish consumption and/or migration into the water. For nematodes, reductions in the top 2 mm occurred due to mortality (but not necessarily consumption by fish), as well as possible migration deeper into the sediments when fish were present