And some more all of it interesting.

Summary of recent genetic analysis performed on Willapa Bay watershed Chinook salmon
Purpose of work:
to extend and update the existing baseline genetic data sets and profiles of Chinook
salmon populations within the Willapa Bay watershed.
Four spawning populations were considered in Willapa Bay tributaries and comprised the North, Willapa,
Nemah, and Naselle rivers.
We sought to answer two questions:
1)
Is there genetic population structuring among the four spawning populations of Willapa Bay
Chinook?
2)
Are the genetic profiles of the four spawning populations distinct enough that we can
reliably accurately identify the spawning population of origin of individual fish?
Samples analyzed included collections from naturally-spawned or -spawning fish and from broodstock
from each of the three hatcheries.
Preliminary results:
1)
Population structuring –
Pairwise
F
ST
values, a measure of population differentiation genetically
comparing each spawning population with all other spawning populations, were all well below 0.01
indicating that the Chinook salmon spawning populations are genetically very similar
.
Principle Component Analysis (PCA), naïve to sampling locations showed substantial genetic overlap
of the four spawning populations. PCA analysis aware of sampling locations still showed significant
overlap among the spawning populations, but the North River and Willapa River populations showed
slightly dispersed clusters and the Nemah and Naselle populations formed even tighter clusters that
almost completely overlapped.
PCA analysis supported the hypothesis that some population
structure may exist in Willapa Bay Chinook, but it is weak.
2)
Identification of spawning population –
Using simulations, we tested the ability of the spawning
population genetic data to genetically assign population of origin to unknown origin individuals.
In
the best case, ~80% of North River simulated fish assigned correctly to the North River spawning
population. In the worst case, only ~50% of Nemah River simulated fish assigned to the Nemah River
spawning population.
The simulations suggested that Chinook spawning populations in Willapa
Bay are too similar to reliably assign individuals to their spawning population of origin.
Preliminary conclusions:
Population structure may exist among spawning populations of Chinook in Willapa Bay tributaries, but it
is weak, and insufficient for reliable and accurate assignment of Chinook with unknown Willapa Bay
population origin.
Please note that this analysis included only Chinook from within Willapa Bay and does not address any
question of genetic assignment of fish originating outside of Willapa Bay tributaries.