I did a little research into the topic, and discovered that the salmon we have here are sockeye salmon (Oncorhynchus nerka) – the same salmon found in the northern Pacific Ocean – but part of a landlocked population that never makes it to the ocean. These are called “kokanee salmon”, but are actually the identical species to the ones found in the ocean. In our case, the population is based in Porcupine Reservoir itself, and they spawn up Cinnamon Creek (and perhaps some of the smaller feeder creeks as well, but I'm not sure about that). It turns out that Porcupine Reservoir is one of just three in Utah that were stocked with a sockeye population. How Porcupine Reservoir was selected for that is something I'd like to find out.
When we got to Cinnamon Creek (after seeing some nice fall color along the way), we discovered that the trail down to the water was too rugged for Debbie to attempt on crutches. So poor Debbie waited for me in the truck while I hiked down to see what I could see. Here are some photos of what I found: