Does transcriptome of freshly hatched fish larvae describe past or predict future developmental trajectory?

Transcriptomic analysis of freshly hatched fish larvae offers insights into phenotype development, yet it remains uncertain whether it reflects parental influence or predicts individual growth. This research scrutinizes the transcriptome of 16 Eurasian perch (Perca fluviatilis) larval families (at mouth opening stage, coinciding in this species with hatching) alongside pre- and post-hatching zootechnical traits. Despite consistent fertilization rates, significant variations in embryonic development and larval performance highlight diverse phenotypes studied. It enabled us to bring our attention to the fact that transcriptome of larvae at mouth opening stage can serve as a window into both the parental contributions and the future performance of the larvae. Our analysis shed light on ribosome biogenesis, neurogenesis, and the cell cycle, as important processes shaping early larval performance. Additionally, we propose a set of predictive, validated gene markers associated with further larval performance and key aquaculture traits, such as selenoo (associated with cannibalism), trim16 (fulton's condition factor), slc15a1 (specific growth factor), and cipc (final weight). This study delves into the descriptive and predictive nature of the transcriptomic portrait of newly hatched larvae, paving the way to comprehend the intricate developmental pathways from fertilization towards juvenile stage. •Larvae transcriptomic profile is a powerful tool to refine aquaculture practices.•Studies linking transcriptomic profile of larvae with their traits are scarce.•Transcriptomic portrait of larvae is both descriptive and predictive.•Freshly hatched larvae yield molecular portrait coming from parents.•We also show that larvae transcriptome can predict their future performance.