The present proposal present a strategy to characterise genes co-regulated with vitellogenin in the salmon louse. By using a rnicroarray-based strategy, a large number ofexpressed genes can be screened and those that are regulated similar to vitellogenin can subsequently be identified and further characterised. This characterisation will involve full-length sequencing, molecular phylogeny aud in situ hybridisation to identify where in the lice transcription occurs. Results from this project will provide n ovel knowledge regarding the reproduction in female salmon louse that may be important in controlling the parasite in the future.