A little more info to quell or increase the confusion on these guys. It wasn't until the 1970s that taxonomists found enough differences between stocks of Dolly Varden that a new species, the bull trout was separated out. In Puget Sound streams, it wasn't until the early 90s, I believe, that bull trout presence was clarified. Until then, it was thought that the anadromous varieties were all Dolly Varden, like in Alaska, and the residents were bull trout, like in Idaho and Montana. Turns out about 90 percent of the fish tested from Puget Sound streams have been bulls, anadromous or residents. The two species are very difficult to tell apart. In BC, one scientist found that by measuring four different sets of meristics (I can't recall which at the moment), he could tell Dollies from Bulls. But Smalma (our local dolly/bull expert) looked at a fair number in Puget Sound streams and found that the method didn't really work on Puget Sound fish. The only real way to tell the two apart is by genetic tests, but given most data these days, if you catch one, you probably got a bull.

Some of the acoustic tagging data in Puget Sound also show that the fish basin hop. It's been shown that some Snohomish and Skagit born fish will move around in both streams, although its thought that they spawn only in the stream of birth. One fish that I tagged on Jetty Island at the mouth of the Snohomish in April was caught downstream of Darrington in the Sauk in August. That's probably why you can't keep bulls in the salt (you're actually not supposed to fish for them; I'm fishin for cutts, ahem). No matter where you are in Puget Sound, you really don't know what basin the fish is from. Skagit and Snohomish basin populations appear pretty healthy and expanding, but populations in other Puget Sound streams are largely unknown and many may be quite small.

Bulls are fall spawners that spawn upstream of almost all other salmon because the eggs need very cold water to successfully incubate. That's why they're found principally in streams draining glaciers or streams that receive lots of snowmelt (like the Hoh, Skagit, and Skykomish).

We're learning more and more about these fish every year, but when I have rod in hand, I'm still hardpressed to call one anything other than a dollie. Because they look alike and have similar behaviors, WDFW manages them as the Dolly Varden/Bull trout complex, and essentially doesn't distinguish between the two.