The Vertical Distribution of Marine Macroplankton. XI. Further Observations on Diurnal Changes

Abstract

1. Details are given of the results of a series of hauls with the 2-metre stramin ring-trawl fished at six different depths in daylight, at dusk, in the dark, at dawn and again in daylight on June 3rd–4th, 1926.2. A comparison is given of the results obtained on the four nights July 15–16th, 1924; June 17–18–19th, 1925, and June 3rd–4th, 1926.3. The importance is stressed of the effects on the type of behaviour shown by any animal produced by the depth at which it is living in the daylight and the speed at which it can swim upwards.