I was combing through old issues of the Santa Clarita Signal from 1971 at work and I found articles from the original opening days at Castaic and Pyramid. Pretty interesting actually. 4000+ people showed up at Castaic to catch bass and trout, pre-striper days haha, and the DFG had serious doubts about whether fish would survive the journey through the aqueduct and into the lakes (they were sure wrong about that!).