Genetic Monitoring for Managers
Types of GEM
The application of microsatellites for stock identification
of Yukon River Chinook salmon.
|Locations of the 10 Canadian and 9 U.S. Yukon
River populations of Chinook salmon surveyed for microsatellite
variation 1987-2003, and the location of the Bio Island test
fishery, where an independent sample was obtained for comparison
with the baseline. [from Beacham et al. 2008]
Because the Yukon River drainage includes spawning populations
of Chinook salmon (Oncorhynchus tshawytscha) in both Canada
and the United States, the fishery is cooperatively managed by
both countries. Their principal goal is rebuilding and conserving
stocks while providing fishing opportunities to both countries.
Knowledge of salmon origins and the relative abundances of stocks
captured in mixed-stock fisheries are important for setting harvest
limits and monitoring the effects of harvests. Mixed-stock analysis
using genetic data is an efficient and effective method for determining
Baseline samples from adult salmon were collected from 19 Yukon
River Chinook salmon populations between 1985 and 2003. Genomic
DNA was extracted from either liver, scales, operculum punches,
or fin clips.
A single microsatellite locus or 9 single-nucleotide polymorphisms
(SNPs) can provide accurate
and reasonably precise estimates of stock composition to country
In this study, fish stock origin was examined using 30 microsatellite
loci and compared to an existing nine-locus SNP baseline. Reliable
population-specific estimation of stock composition was obtained
with a minimum of five microsatellite loci.
|Salmon play an important role in economies,
traditions, and recreational opportunities throughout their
Beacham et al. (2008) examined genetic variation for 19 populations
of Chinook salmon from the Yukon River using microsatellite loci
and an existing single-nucleotide polymorphism (SNP) baseline.
Both markers systems provided accurate and reasonably precise estimates of salmon stock composition
to country of origin at a fraction of the cost traditional methods.
|Accuracy of assignment of individual Chinook
salmon to country, region, and population as a function of
the number of loci examined. [from Beacham et al. 2008]
Using this approach, managers can accurately and precisely allocate
Chinook salmon harvest quotas to the level of region or major
drainage, providing a powerful tool for assessing and regulating
fisheries. This information can be used for apportionment of harvests,
characterization of run timing and migratory patterns, stock run
reconstruction, stock recruitment models, and risk assessment.
The rapid turn around of a genetic monitoring approach allows
in-season management. A combination of genetic mixed stock analysis
and sonar provides a convenient and cost effective method to monitor
all stocks simultaneously. More details can be found at: http://alaska.fws.gov/fisheries/genetics/pubs.htm