If Dolly Varden breed at different times or in different locations from bull trout –even when their ranges overlap– they could be different species. If their spawning areas overlap and they can interbreed to produce viable offspring, they would be subspecies at best; otherwise they would be the same species grouped into populations of varying genetic expression, and these groups would be analogous to what we call “races” among people.

That’s just what I understand. I’m no ecologist (working on it), but I did stay at a Holiday Inn Express.

This copied from a website
“Much ado is often made of the differences between very similar fish. While arctic char have long been prized for their beauty and succulent sweet flesh, Dolly Varden char have not always had the same cachet.

And then there are bull trout. Now the focus of major conservation efforts in Alberta, British Columbia, and the western United States, bull trout were thought of as garbage fish only a few decades ago.

In fact, these three members of the char family are extremely difficult to tell apart. Yukon fisheries officials are now relying on genetic tests, the only conclusive way to tell one species from another, to confirm which species live where in the territory. …”
copied from http://www.taiga.net/yourYukon/col141.html if you wish to read the rest dealing with differentiating between Arctic Char, Bull Trout and Dolly Varden. But, to me those first 2 paragraphs say it all, and the positive identification should be left up to those willing to do it (and the ones that have ample time on their hands and a large surplus of extra Benji’s laying around). I can tell you this much, I won’t be the one. So, for now, it looks like that could have been either one! Nice CHAR! Aptly named now as such! It is what it is.

Dave