Genomics-Enabled Mixed-Stock Analysis Uncovers Intraspecific Migratory Complexity and Detects Unsampled Populations...

Area of Science:

• Ecology
• Genetics
• Conservation Biology

Background:

• Understanding population contributions to harvests is vital for migratory species conservation.
• Genetic Stock Identification (GSI) relies on reference samples, but source populations can be remote or unknown.

Purpose of the Study:

• To investigate intraspecific variation in walleye (Sander vitreus) populations in two northern Quebec lakes.
• To develop and apply a genetic panel for GSI and assess migration patterns.

Main Methods:

• Developed a panel of 303 single-nucleotide polymorphisms (SNPs) using genotyping-by-sequencing.
• Genotyped 1465 walleye and assigned individuals to source populations using RUBIAS and STRUCTURE.
• Assessed individual migration distances using GPS coordinates.

Main Results:

• Achieved 93% assignment consistency between methods in the main lake, identifying five major source populations and up to three small unsampled ones.
• Observed significant differences in average migration distances among populations.
• Attributed 99% assignment consistency in a neighboring lake to two distinct walleye populations.

Conclusions:

• Complex population structure and migration in the main lake suggest habitat heterogeneity and potential for local adaptation.
• Combining GSI analytical approaches enhances result robustness and detects intraspecific diversity crucial for conservation.
• The study provides valuable insights for managing walleye populations and informing conservation strategies.