Long rough dab (Hippoglossoides platessoides) is an important flatfish fish species in the north Atlantic arctic and sub-arctic marine foodweb that could be vulnerable to contaminant exposure from offshore petroleum related activities. The study was conducted to map transcriptome responses in long rough dab precision cut liver slice (PCLS) culture exposed to benzo[a]pyrene (BaP). BaP is a polyaromatic hydrocarbon (PAH) which is among the most toxic compounds found in crude oil. PCLS culture was performed under 10 µM BaP exposure for 72 h and transcriptome analysis (RNA-seq) analysis was performed to characterize de novo transcriptome of the liver and identify genes responding to BaP exposure.