Upgraded research tool allows scientists to pinpoint the origin of individual salmon.
From the Northwest Fisheries Science Center, NOAA Fisheries
NOAA scientists have upgraded a crucial tool for Chinook salmon conservation. This genetic reference tool allows researchers to pinpoint the river system individual fish come from, enabling more precise management and protection of threatened and endangered populations.
“It’s like giving every fish a unique genetic fingerprint,” says Donald Van Doornik, a NOAA Fisheries fish biologist and lead author of a new paper describing the work in the North American Journal of Fisheries Management. “We can use this fingerprint to figure out where that fish came from by comparing it to other fish’s DNA.”
Building A Comprehensive Genetic Database for Chinook Salmon
Genetic stock identification is a scientific method used to determine the origin of an individual organism, such as a fish, by analyzing its genetic makeup. Scientists compare the DNA of an unknown individual to a reference database of known populations. They can identify the most likely stock or population from which the individual originated or the composition of mixtures of fish caught in the ocean.
If we could identify the specific Chinook populations contributing to mixed-stock fisheries, then we’d be able to design more effective conservation and management strategies.
However, developing comprehensive genetic databases for species with wide geographic ranges, such as Chinook salmon, has been challenging. The species has a vast geographic distribution and a diverse genetic makeup. The limitations of existing genetic data and technology have also hindered the development of a reliable, range-wide genetic stock identification database for Chinook salmon.
Other researchers developed a coastwide genetic database for Chinook salmon using microsatellites, which are simple repeats of genetic bases in the genome, more than a decade ago. However, this technique is difficult to standardize among labs and provides limited information compared to new methods. The updated database uses newer technology that surveys genetic sequences and individual base differences among individuals and populations.
A Genetic Tool to Pinpoint a Chinook Salmon’s Origin
Federal, state, tribal, and academic researchers across the West Coast collected genetic data from various sources across the Chinook’s entire geographic range. Then, they assembled a genetic database that scientists can use to accurately identify a salmon’s origin. Rigorous testing and simulations ensured the database’s reliability. Finally, they employed a hierarchical analysis approach to pinpoint a salmon’s specific home.
By collecting, standardizing, and analyzing the DNA of thousands of salmon from various populations, researchers developed a standardized genetic reference for Chinook. Accurately identifying the origin of individual salmon allows managers to make informed decisions about harvest quotas, protect endangered populations, and monitor the health of different stocks. Scientists can also use this information to study migration patterns, genetic diversity, and the impact of specific fisheries and environmental factors on salmon populations.
