MESH SELECTION AND FILTRATION EFFICIENCY OF THE CONTINUOUS PLANKTON RECORDER

The filtration efficiency [volume filtered/(inlet aperture area X dist ance travelled through the water)] and retention of copepods by the Co ntinuous Plankton Recorder (CPR) were measured in sea trials. Filtrati on efficiency was independent of tow speed (n = 14 trials, range of sp eeds 5-13 knots, F1.12 = 0.1, P = 0.73), but was influenced by the ext ent to which the body of the CPR was sealed. The retention of copepods on the silk filtering mesh routinely used in CPRs did not differ sign ificantly from that predicted for a 270 mum nylon mesh and did not var y with tow speed.