Pretty rare fish but I have seen a couple in the 40+ years I have been examineing fish insides, the first one I ever saw was in 1962 about a ten pound steelhead from a Quinault area stream, it was early December and very bright. Had huge gonads that were sperm like with small orange, tapioca looking, eggs evenly distributed throughout.
The other was a coho that had one gonad of each very normal looking fish from the gulf outside of Icy Strait in early August.