Population abundance in arctic grayling using genetics and close-kin mark-recapture

Area of Science:

• Aquatic Ecology
• Conservation Genetics
• Fisheries Management

Background:

• Arctic Grayling (Thymallus arcticus) are widespread in Yukon, but population structure and abundance are poorly understood.
• Accurate population estimates are vital for effective management and conservation of freshwater fish populations.
• Estimating abundance in wild populations presents significant challenges.

Purpose of the Study:

• To estimate the population abundance of Arctic Grayling in the Yukon Territory.
• To assess population structure and genetic diversity using genetic markers.
• To demonstrate the utility of the close-kin mark-recapture (CKMR) method for fish stock assessment.

Main Methods:

• Genotyping of 1,104 Arctic Grayling from two Yukon systems using 38 microsatellite markers.
• Identification of parent-offspring pairs (POPs) from adult and young-of-the-year samples.
• Application of COLONY and CKMRsim software for POP identification and abundance estimation via CKMR.

Main Results:

• Genetic analysis revealed population structure and assessed genetic diversity.
• COLONY and CKMRsim yielded similar, indistinguishable estimates for census size.
• Estimated Arctic Grayling census size was approximately 1858 (95% CI: 1259-2457) and 1812 (95% CI: 1229-2389).

Conclusions:

• The close-kin mark-recapture (CKMR) method is effective for estimating Arctic Grayling abundance.
• This genetic approach provides valuable data for informing management and conservation policies.
• The CKMR method shows promise for other fish species where random sampling assumptions can be met.