There is a considerable scientific knowledge about the general biology and ecology of krill, but the genome sequence of E. superba is not yet available and therefore the systematic sequencing of cDNA libraries represents a powerful approach to identify large numbers of transcripts. Recently, Clark and colleagues have generated the first 454 sequencing data for a pelagic Antarctic species and focused their attention on the typical stress genes of the Heat Shock Protein family. In order to increase the probability of identifying circadian clock genes, or clock-controlled genes, we have developed and sequenced a normalized cDNA library from krill sampled at different times of the day over a complete 24-hour cycle. Using the 454 Titanium technology we have identified 89,230 high-quality reads.