Population structure and genetic diversity analyses reveal isolation that may imperil the northernmost colony of the endangered Australian sea lion

Marine environments are experiencing rapid warming, substantially altering ecosystems. Populations at the edge of a species’ range are more vulnerable to environmental change as they are first affected and may have limited dispersal opportunities. This vulnerability may be exacerbated in species with specialised foraging and breeding strategies. The Australian sea lion (Neophoca cinerea) is an endangered otariid species that breeds across a ~3000 km range in southern Australia. At the most north-westerly edge of the species’ distribution, Australian sea lions breed across multiple islands within the Houtman Abrolhos Archipelago, Western Australia, a tropical-temperate location affected by marine heatwaves. This study aimed to examine the genetic structure and diversity of the Australian sea lions from the Houtman Abrolhos Archipelago compared to other populations in the species’ range. One hundred and twenty-five individuals, nineteen from Houtman Abrolhos, were genotyped from nineteen ..., , # Population structure and genetic diversity analyses reveal isolation that may imperil the northernmost colony of the endangered Australian sea lion

Dataset DOI: [10.5061/dryad.3ffbg79xw](https://doi.org/10.5061/dryad.3ffbg79xw)

## Description of the data and file structure

### Files and variables

#### File: ASL_Abrolhos_code

**Description:** Text file containing R code used to complete analysis.

#### File: pop_ID_metadata_ALL.csv

**Description:** Metadata for each individual. Variables include, id (individual), sex, population (sample colony location), lat, long, metapopulation, state, age, date collected, plate details and dataset ID.

#### File: Report_DNeof24-8961_1_moreOrders_SNP_mapping_2.csv

**Description:** This is the SNP export file received from Diversity Arrays Technology. SNP 1 Row Mapping Format: \"0\" = Reference allele homozygote, \"1\" = SNP allele homozygote, \"2\"= heterozygote and \"-\" = double null/null allele homozygote (absence of fragment with SNP in genomic re..., ,