Stripers do spawn successfully in lakes with no major rivers. San Antonio reservoir (central coast) is an example of this. No stripers have been stocked there for years and yet there are all sizes in the lake. There is a river that comes in to the lake but it does not flow year round. I've talked with people more knowledgeable than me on this subject and they told me that stripers can spawn in the thermocline. I'm not a biologist, this is just what I have heard.