Zooplankton of the St. Lawrence Estuary: The Imprint of Physical Processes on its Composition and Distribution

摘要: Studies on the composition and distribution of zooplankton in St.Lawrence estuary are reviewed discussed with special attention to dominant role physical oceanographic processes. The 350 km-long is divided two parts by a 50 m-deep sill, which isolates Lower from shallow (<100m) Upper estuary. At upstream end estuary, planktonic (Eurytemora affinis) epibenthic (Ectinosoma curticorne) copepods mysids (Neomysis americana) maintain endemic populations at front salt wedge (S = 1−15‰). Further downstream, abundance appears pass through minimum before increasing 100 basin adjacent sill 25−30 ‰). There copepod dominated Acartia longiremis, Eurytemora herdmani Calanus finmarchicus. In belong genus Calanus,mainly C. finmarchicus some hyperboreus their later developmental stages (CIV-CVI). A few smaller species frequent, but Pseudocalanus surprisingly rare. Other important taxonomic groups euphausiids Thysanoessa raschi Meganyctiphanes norvegica,which concentrate dense sound scattering layers head along deep channel.