Areal population density and detailed behavior of fish schools and their interaction are continuously monitored over continental-shelf-scale areas spanning thousands of square kilometers by ocean acoustic-waveguide remote sensing. In addition there is disclosed a method of improving the operating efficiency of a refinery by reducing fuel gas production and simultaneously producing high quality gasoline blending components of low volatility. The core element defines ink reservoirs in fluid communication with the molding. A mask is then created from the dilated data set and the reference object data set is filtered by the mask to produce a resultant object data set.