Chromosome-level assembly of the Critically Endangered school shark, Galeorhinus galeus (Linnaeus, 1758)

The school shark, Galeorhinus galeus (Linnaeus, 1758), is the only extant species within its genus and is widely distributed in benthopelagic habitats of temperate coastal regions. Fishing pressure has caused global population declines by more than 80%, resulting in the species being listed as Critically Endangered. Here, we present the first chromosome-level, haplotype-phased reference genome assemblies for G. galeus, including assemblies of both male and female individuals. The 4.81 Gbp male genome was assembled from PacBio HiFi and Dovetail Omni-C proximity ligation sequencing data, and the 4.52 Gbp female genome was assembled from PacBio HiFi data scaffolded via homology to the curated male genome. Both genomes are >92% BUSCO complete and contain ~60-63% repeat content. Analysis of methylation levels and single nucleotide polymorphism density across chromosomes revealed several regions where high SNP density co-located with relative hypomethylation, indicating a reciprocal relationship between these two features. These genomes are a valuable resource enabling future genomic studies to inform population management and conservation strategies for this Critically Endangered species.