The extent of hybridization between bull trout (Salvelinus confluentus) and brook trout (S. fontinalis) across Alberta’s Eastern slopes

Identifying hybridization provides insight into risks associated with non-native species. Bull trout (Salvelinus confluentus), a charr native to Alberta, face population declines across their range and one risk may include hybridization with non-native brook trout (S. fontinalis). However, the extent of introgressive hybridization throughout Alberta is not well understood. Therefore, we aimed to quantify bull x brook trout hybridization in three ways: 1. the observed hybrid presence across Alberta, 2. the proportion of post-F1 hybrids (e.g., F2 and backcrossed), and 3. the hybrid proportion relative to brook trout in well-sampled watersheds. Using two panels of >1,000 diagnostic Single Nucleotide Polymorphisms, we identified 35 F1 and 7 post-F1 hybrids (n = 42 total) across 10 HUC 8 watersheds. Our findings show hybridization throughout the bull trout range, however, with few post-F1 hybrids found, little evidence of extensive hybrid introgression was observed. The misidentification ..., Genetic information on individual Salvelinus spp. samples (n=1200) collected across Alberta's Eastern Slopes. Files are data formatted for ADMIXTURE 1.3 software analyses., , # The extent of hybridization between bull trout (Salvelinus confluentus) and brook trout (S. fontinalis) across Alberta’s Eastern slopes

[https://doi.org/10.5061/dryad.gtht76hx8](https://doi.org/10.5061/dryad.gtht76hx8)

## Description of the data and file structure

All *Salvelinus spp.* fin clips were collected by Alberta Environment and Protected Areas (AEPA) staff between 1999 - 2022 using either electrofishing, angling, or trap netting as described in the manuscript. Samples spanned 24 Hydrologic Unit Code (HUC) 8 Watersheds in Alberta. The datasets contain Single Nucleotide Polymorphisms (SNPs) in ordinary PLINK format for analysis of ancestry estimates using ADMIXTURE 1.3 software (Alexander et al. 2009).

### Files and variables

#### File: AB_hybridization_2025_nonBLT.map

**Description:** Ordinary PLINK format file containing genetic map information on 1174 Diagnostic nonBLT (non-bull trout) loci.

#### File: AB_hybridization_2025_BKT.map

**Description:** Ordinary PLINK for...,