Hudson Bay Co used to send brigades down as far south as the Sacramento Valley. There were some pretty productive beaver streams discovered by Jedediah Smith when he went through in 1826. If I recall correctly his men trapped a couple thousand in northern California on their way up north to Oregon.
And like coastal Oregon, most of the population found in tidewater.

No brook trout in California. But they do have artic grayling in a few of the streams where the beaver will be introduced. And don't forget about the cutthroat trout. Some of these trout are only found in northern California.