By spawn fishing, I'm thinking you mean sight fishing right?

How good sight fishing is has everything to do with conditions, with the most important factors being water clarity, wind, and the timing of the spring warm up periods.

This year was my best sight fishing year since 2003. It was good for me because I hit a lot of days with good conditions. The result was a 12, a 13 and two 15's. Last year by comparison, there was tough sight fishing conditions at most places due to the prolonged rains in March.

As far as fishing during the spawn goes, the way that you can hurt it is by catching and killing fish. Luckily in California, this is not a huge problem. One of the 15lbers I caught this year, I have caught twice before, at 12lbs and at 14lbs. As long as you practice catch, care, and release, you should enjoy good fishing every spring.