Lake trout hybrid?

I recently caught a lake trout on Flaming Gorge Reservoir, which straddles the Utah-Wyoming border, which had markings which were quite different from any other lake trout I caught.  Its spots were much larger and more prominent than those on other lake trout, and some of them were long and worm-like.  Was this fish some kind of hybrid?  Sorry about the lousy quality of the pictures -  I snapped them as the fish was thrashing around in my net before I released it.

Cool fish. It might be a Splake.  Brookie/Laker hybrid.

Variations in color and spotting can vary dramatically within the same species of trout/char, especially when comparing spatially disconnected populations. When I fished for lakers in CA, many of the ones I caught had the worm-like markings on the back, and some of the smaller ones had vibrant spotting.

The one potential hybrid possibility would be a splake, a cross between a laker and a brook trout. However, most splake are artificially produced and it's very rare to find natural occurrences of them. I don't believe splake have been stocked in Flaming Gorge. It's likely your fish is a pure laker.