California lake speeding law?

We recently where pulled over at lake Perris for speeding in a supposedly no wake 5 mph zone with our wave-runner The area was previously not limited by speed and wasn't clear on the location of the speed limitation. The officer pulled us over and issued a ticket to us even though we asked him to let us off with a warning and that we wouldn't do it again and we didn't know because it was previously no speed limit and it wasn't posted well. Also the cop didn't have radar on his wave-runner Can anyone give me some tips on how to fight the ticket or steer me towards a website that talks about california recreational water laws.