Vertical distribution of large planktonic animals in the cold waters of the Labrador current north of the Gulf Stream Frontal Zone

The vertical distribution of macroplankton was studied in the region of the Titanic wreck (41 degrees 39' N, 49 degrees 58' W), which was investigated over several years. In 1999, the area was located in the cold Labrador wat ers north of the Gulf Stream Frontal Zone. Isaacs-Kidd midwater trawls of S amyshev-Aseev modification were used for sampling; direct visual counts of macroplankton from the Mir manned submersibles were also carried out. Quant itative data on the vertical distribution of the main groups of macroplankt on were obtained. In the region under study, the expected (observed before) increase in the biomass of pelagic shrimps at a depth of about 1000 m was not observed. This phenomenon was observed in 1995 and 1998, when the Gulf Stream Frontal Zone passed directly across the surveyed area. This phenomen on seems to be strictly related to the Gulf Stream Frontal Zone. We explain this as a result of the exploitation of the younger Arctic-Boreal communit y by the more "mature" community of the waters of the Gulf Stream.