The name LOKI describes a non-invasive method of sensing zooplankton in the water colum. The method itself has been initially developed by Jan Schulz and has undergone a couple of refinements. Today it is a foremost technology for imaging small species of less than 1 mm body length 'on-the-fly'. The LOKI gear is operated from research vessels in double oblique hauls and images organisms and particles that pass by an observing window. These information are linked to simultaneously measured environmental parameters and allows a precise assignment of physical parameters and the appearance of objects.