Total plankton from vertical samples is estimated in terms of numbers, volume and dry weight per m3. Three stations were sampled, by day and by night, over a period of thirteen months, using both a 58 m.p.i. and a 74 m.p.i. net clamped together. Three stations had total depths of 12, 40 and 750 m respectively. Some relevant and contemporary climatic and hydrographic factors are shown. The relative catches of the two nets are shown for all three measures and their relative catching ability is discussed.