Just out of curiosity, why Los Vaqueros? Also, I havent looked into the issue you are checking out, but I do know that in many lakes the issue with stocking trout has nothing to do with frogs or any other amphibian. It has to do with the potential for stocked trout to get downstream of the dam and inter-breed with steelhead. Genetic introgression is a bad thing. This is why the lower Lagoon does not get stocked anymore. Im not gonna get into it, but one look at the outflow of the Lagoon, and knowing it flows through heavily populated areas before reaching the ocean, is pretty much all I need to be pissed about the whole process. But dont worry, triploid stockings are on the way, just no telling how long before implementation.