Variations in the size of Antarctic krill, Euphausia superba Dana, in small swarms

Abstract

Studies on the characteristics of krill (Euphausia superba ) in individualswarms require sampling methods which ensure that the swarms aresampled discretely. A study on the size composition of krill swarmsusing an enlarged Longhurst-Hardy plankton recorder (LLHPR) and anechosounder reveal that the length frequency distributions of krillin adjacent swarms were often significantly different. In contrast,length frequency distributions from within the same swarm were notusually significantly different and any differences were probablycaused by several swarms overlapping in the LLHPR samples. The sizeof krill in the samples showed as much variation over short distances(several hundred metres) as over longer distances (several kilometres).