A UC Davis study has explored the theories of spring Chinook salmoon run trends and could help in restoring dwindling numbers of springer salmon making their way back in from the Pacific.
The Sacramento Beehas more on the study’s potential impact and provides some insight as to why some kings and steelhead spawn earlier and the impact such research can have from a conservation standpoint:
This study provides new evidence that “springers” and other salmon that migrate upstream from the ocean to spawn early in the year are genetically different than later migrating populations.
This evidence could be used in the fight to protect groups of steelhead and Chinook salmon in Northern California and the Pacific Northwest. An earlier petition by conservation groups to list them under the Endangered Species Act in 2011 failed because it wasn’t clear that the groups were distinct.
Across the Western states, several salmon populations are listed under the Endangered Species Act, including Central Valley spring-run Chinook in the Sacramento River and tributaries upstream.
For the steelhead and Chinook species of Pacific salmon, some populations migrate earlier in the season. This group of “premature migrators” leave the ocean to travel upstream before their sexual organs mature and while the snowmelt-fed flows are receding. They migrate further upstream than their counterparts and wait in cool freshwater pools until they reach sexual maturity and spawn around the same time as the late runners that migrate as sexually mature adults.
These premature migrators, spring-run Chinook and summer steelhead, are special. For one, they’re fattier, and are valued for their taste. But these populations have also suffered drastic declines across their range and haven’t fared as well as the later migrators.
The work, published in the journal Science Advances by Michael Miller at UC Davis and collaborators at other institutions, examined the genetics of these salmon populations and may have wide-reaching implications for conservation decisions on imperiled groups of many species.