Chromosome-level reference genome and annotation of the Arctic fish Anisarchus medius

Abstract Anisarchus medius (Reinhardt, 1837) is a widely distributed Arctic fish, serving as an indicator of climate change impacts on coastal Arctic ecosystems. This study presents a chromosome-level genome assembly for A. medius using PacBio sequencing and Hi-C technology. The PacBio assembly totaled 739.07 Mb across 697 contigs, with a Contig N50 of 10.004 Mb. Hi-C mapping yielded 23 chromosomes, with a successful mapping rate of 90.53% and a Scaffold N50 of 30.20 Mb. Genome BUSCO integrity was 97.05%. Repetitive sequences accounted for 240.83 Mb (32.58%) of the genome. Non-coding RNA annotations included 4,928 rRNAs, 9,663 tRNAs, 347 snRNAs, and 21 snoRNAs. A total of 30,345 protein-coding genes were identified, encoding 46,603 proteins, with a BUSCO completeness of 94.98%. Molecular pathway related to the endocrine system, carbohydrate metabolism, folding, sorting, and degradation, signal transduction, and transport and catabolism contribute to A. medius adaptation to extreme Arctic environments. This high-quality genome provides valuable genetic resources for understanding Arctic adaptations and supporting polar ecological conservation and management.