Depth-recording with Plankton-nets

Abstract

IT is well known that there is great variation in the vertical distribution of various plankton organisms, but up to the present the actual depths from which net-collections have been made has never been known with certainty. To help in the study of the vertical distribution of marine zoo-plankton, the Admiralty very kindly sanctioned the loan of an instrument which records graphically, on a drum worked by clockwork, the depth at which a net has been fishing during the whole of its period under water. Results obtained with this apparatus indicate the necessity for an accurate knowledge of the depth at which the net has fished.